Translated by João Vitor Coutinho
Edited by Pavel Volkov

In the Neocene, South America was completely separated from North America. Throughout almost the entire Cenozoic, the continents were also separated, and in each of them flora and fauna developed independently. But then, in the Pliocene, the Isthmus of Panama formed between the continents, and the subsequent invasion of northern species destroyed the endemic South American fauna.
In the Neocene, the connection between the continents was interrupted again: the movement of small lithospheric plates in the Caribbean Sea, caused by the expansion of the Atlantic, tore the Isthmus of Panama and made it impossible for further exchange of the faunas of the two continents. For a time, species from South America could have entered the north through the intermittent Antillean Bridge – a chain of islands formed by the Antilles and a large island called Great Antigua. Due to this, cursorial caviomorph rodents, the deermaras, appeared in the north and flourished in the plains of North America. However, later this movement of fauna also became impossible.
In Neocene, South America is gradually shifting south towards the Pole. The plains of Patagonia are already in an area of temperate climate, with heavy snow falling in winter and it is pretty cold in the mountains. But the plains of the northern part of the continent are still in the area of tropical and subtropical climates, and a variety of thermophilic species of plants and animals dominate here.
To the south of the area of continuous rain forests, there is a belt of light forests. This landscape is a bit reminiscent of the areas of East Africa in the Pliocene and Pleistocene: grassy plains are cut by rivers, in the valleys of which vast shallow lakes are scattered. Outcrops of rock formations rise above the plains, forming mountain plateaus with caps of evergreen forest. This area is very attractive for various species of animals, from the smallest ones to true giants.
A bird's feather lies among the grass. Judging by its shape, it is a flight feather from a bird’s wing – it is slightly curved, and its vexillum is asymmetrical. It served its owner faithfully for a long time: its edges were slightly frayed, and the vexillum in some places was gnawed by parasites.
A small motley lizard with a thin long tail climbed onto this feather, attracted by the sunny place, and closed its eyes, enjoying the warmth of the sun. It sits on this feather, as if on a palm leaf, and there would be enough space for one or two more of its relatives. But the lizard itself was not some kind of dwarf, but a medium-sized adult reptile. It’s just that the feather on which the lizard decided to bask itself is about three-quarters of a meter long.
The lizard is not alone in this world: it is surrounded by much stronger and more ferocious animals, and a small reptile needs to be constantly on the alert so as not to become someone’s food. The lizard watches with one eye several huge birds feasting nearby. They are hunting herons, flightless carnivorous birds, one of the most important predators in the Neocene plains of South America. They hunt in a group, and their behavior helps them to catch the swift-footed inhabitants of the plains, which are dangerous for other predators. About half an hour ago, they killed a young giant paca – it would not be easy for a lonely hunting heron to do it, since this monstrous rodent weighs much more than the predator itself. By acting together, the birds inflicted many wounds on the giant paca with their pointed, serrated beaks, and the animal simply bled out and died.
Now the hunting herons are enjoying their prey. Twitching their necks, they tear out pieces of meat from the sides of the killed giant paca and convulsively gulp them. From time to time, they click their beaks, turning towards each other. Despite the collective method of hunting, a strict hierarchy reigns in the flock of birds, and the weaker individuals eat furtively, while the dominant birds are busy with swallowing of their portions of meat. Hunting herons have tiny reduced wings, so the huge feather lying in the grass simply cannot physically belong to them. But other large birds are found in the plains of South America.
Like a cloud covered the sun for a moment, and a gust of wind stirred the grass. The lizard jumped off the feather and disappeared among the tall grass stems. Experience and instinct teach it to be extremely careful, and this has saved its life more than once. The hiding reptile hears a loud flapping of huge wings and a dull sound of feet hitting the ground. Without tempting fate, the lizard finds its hole and hides there.
A monstrous bird with strong legs, large wings and bare head and neck wanders among the grass. The bird folds its wings, and at this moment it becomes noticeable that one wing is missing a flight feather. A huge territory – about a hundred square kilometers, is the possession of this very bird, and the owner regularly flies round these lands. The owner of the giant feather, a bird called akatu, landed on the ground next to the hunting herons not by accident: due to its keen sense of smell, this bird felt that the hunt of the flightless herons had ended successfully, and now wants to get its share by the right of might. There are many hunting herons – more than a dozen. But these birds are too stupid to take hold of the strength in numbers and drive off the great bird. And the akatu knows how to make an irresistible impression on any of the local predators: having opened its huge wings, the akatu bends its head, inflates its throat bag and roars loudly. In response to this display, hunting herons click their beaks, and one of the birds makes an aggressive attack towards the akatu. However, akatu is not afraid of such solitary attempts to intimidate: the bird makes a two-meter jump with open wings, and its bellow, reinforced by its swollen throat sac, resounds the plain again. The hunting herons can’t stand it. One after another, long-billed birds retreat from the prey and seek protection from each other. The most hungry individuals could stay with the prey longer, but the monstrous akatu continues driving them away, and finally all hunting herons retreat one after another. The last of the birds managed to tear off a piece of meat, but as soon as it moved away from the carcass, another heron immediately took this meat from her. As for akatu, it is not at all interested in the appetences and problems of hunting herons. A large bird plunges its featherless head into the carcass of a giant paka, and begins to tear meat with its sharp beak.
The bird that has lost a huge feather rarely, but in regular way appears in this area – it is a part of the vast possessions of the akatu, and every day the bird flies in search of food to another place. Such large predators always have vast territories and live in sparse populations. The bird that has taken advantage of the hunting success of the hunting herons is an adult akatu male. It features a bright blue throat and a large throat sac that resonates with the powerful and sonorous cry that the akatu uses to claim food and territory to other inhabitants of the plains and mountains. Akatu belongs to the cathartid family – carnivorous birds similar to the vultures of the Old World. In the epoch of ecological crisis, many species of birds of prey became extinct, but the ancestor of the akatu survived, and after millions of years turned into a creature of amazing appearance.
The akatu male flies over the plains, surveying them. Its sensitive nostrils capture thousands of smells of the heated ground, complementing the picture of the world spread out under the wing of this bird. Soaring high in the sky in the rising currents of warm air, this giant bird represents a magnificent sight. Its habitat in the human epoch was called the Gran Chaco. In Neocene, the Gran Chaco is a real “patchwork” of grassy plains, forests, rivers and lakes. Dense forests grow mainly along the banks of water bodies, and in the savannah trees form open woodlands or grow in separate groups among grasses. In the Gran Chaco of the Neocene epoch, the climate is seasonal: the wet season alternates with drought. In the dry season, reservoirs can dry up, and rivers turn into strings of shallow ponds in the channel, where helpless aquatic inhabitants gather. On the contrary, in the wet season, rivers can overflow for many kilometers, turning the plains into shallow lakes and swamps. But during floods, the inhabitants of the plains, which do not like water, have the opportunity to escape: here and there among the plains, outcrops of rocks rise, like islands in the ocean. They are badly destroyed by time and often look like medieval castles of the human era or some kind of bizarre sculptures. The tops of the old mountain plateaus are overgrown with forest, and here morning fogs give life to many plants and animals that are not found anywhere else, even on the nearest similar plateaus. Four-legged predators will not be able to climb here, but the rocks do not represent an obstacle for the strong wings of the akatu. Here, in rocky niches, akatu nests, and here the male has chosen a place for a new nest.
Akatus form pairs for many years, and even for life. Birds of the same pair are very attached to each other and spend a lot of time together. But the formation of such a pair is preceded by several seasons of test nestings, which sometimes may have an unsuccessful result. The male akatu is single, and he approaches the choice of a life partner especially carefully. For nesting he chose a convenient niche in the rock, protected by an overhanging stone cornice and several strands of vines rooted higher in the crack of the rock. It is a great camouflage for the nest, and in addition, the vines protect the nest from rain with their wide leaves. The male akatu already nested in this place last year, and before him an old female of the same species lived in this place for a long time. While she was alive, the male akatu did not even try to encroach on her territory, but one day she disappeared somewhere, and the young male immediately took this convenient place, leaving his former place of residence. He threw out of the niche the upper part of the old nest, and threw on its base many large branches found below to make the frame even stronger – if he manages to get a family, the nest will have to withstand the weight of a pair of the largest flying birds of the Neocene world, and their offspring.
During the day, the male akatu searches for food: he hunts large animals himself, or takes prey from other hunters, using his gigantic size and brute strength. After the hunt, having rested, he continues to build the nest. In the evenings over the plains a prolonged rolling call is heard – the mating call of the akatu male. This huge bird repeats it for many days in a row: akatus live far from each other, and it can be difficult to find a nesting partner.
Gradually, the building of the nest comes to an end: the male begins to drag not only twigs and branches, but even whole bushes torn from the ground. Tamped down by his feet, they form an elastic bedding of the nest. The male akatu rests very little: the birds have a long period of raising offspring, and he is in a hurry to finish the nest, even if the female has not appeared on the territory. At akatus nest is one of the elements that strengthen the relationship of birds: a male without a nest does not attract females.
Every evening, the male akatu calls on the female almost until dark, and sleeps very little. In the mornings, when the sun warms up the earth enough and updrafts appear, the large bird easily takes off in a weak headwind.
This male already had several failures in succession in choosing a mate. Last season, the female turned out to be too aggressive: obeying the heightened parental instinct, she did not allow the male with the prey to approach the chick. As a result, the chick died from malnutrition – she could not fully feed it herself, while protecting the chick from the male. When the weak chick began to learn to fly, it simply fell out of the nest and crashed. After its death, nothing else connected the mates anymore, and that female flew away.
The male akatu is ready to call on the female not only in the evening, but also during the day. While the dry season comes to an end, the pair should form and begin to incubate the clutch: the chick should have time to grow up at the most favorable time of the year. Therefore, the akatu male begins daily mating calls even earlier: around the noon. Hovering over the grassy plains scorched by the sun, he screams, inflating his throat sac. The huge bird is noticeable from afar, and this tactic bears fruit: when the male flew over a half-dried river, he heard a distant answer to his call. For the sake of the great purpose of procreation, the male akatu violated the invisible, but well-guarded borders of the neighboring area, and uttered a call-out cry once again. There was no doubt: he received an answer again. In addition, it was not the voice of a male, but of a female. From the top of one large tree that grew in the river valley, a powerful representative of his species – a young and obviously ready for nesting female – flew up to meet the male. Akatu females are larger than males and weigh more than they weigh. Usually the male is careful in his relationship with the female, but at some moments, he shows remarkable courage. It happened so in the first minutes of the meeting of the two feathered giants: the male chased after the female, and, accepting his rules of the game, she began to flee from him, like a hunted prey. At this moment, the birds checked each other: the female assessed the speed and agility of the male, and the male – the ability of the female to obey. Having caught up with the female, the male made her fly sharply upward, and then followed her, overtook her, and turned to the rock, where he had an almost finished nest. The female followed him, keeping behind and slightly below.
Landing on the nest, the akatu male stretched its half-lowered wings like fans, and began rhythmically stepping from one foot to another, raising his head and displaying the female the blue skin on his throat. At this time, his swollen throat sac swayed to the beat of his rhythmic steps. The female, perching on the edge of the nest, watched the male displaying a slow and awkward dance. Then the most important moment in the courtship of akatu male came: bowing his head and showing the attackable back of his head to the female, he pulled a twig out of the nest and gave it to the female. Bowing her head, the akatu female carefully took a twig from his beak, and stuck it back into the bottom of the nest. Mutual trust of the birds was achieved and a new akatu pair formed.
In other birds of the Gran Chaco, the courtship ritual is much faster, and the partners do not follow any complex rituals too much. Right under the nest of akatu small beetle birds – a suboscine species of passerine birds – make their nests. The mating season at this bird stretches for more than six months, and in the same rainy season, beetle birds manage to hatch chicks three times. The male of this bird settled under the nest of the akatu at the time, when the male threw thick branches on the base of the old nest. The huge predator many times saw a shiny green bird with bright red belly and two long black “antennae” above its eyes scurrying around its nest. However, he did not drive this little feathered neighbor away: it is difficult for a large akatu to catch a small nimble bird. The presence of a beetle bird is even beneficial for the large bird: this small bird catches skillfully the mosquitoes, stinging bare head of akatu, and flies that are attracted by food debris in the akatu’s nest. In the evenings, when the mosquitoes are especially active, the male akatu felt that a small beetle bird was constantly keeping next to him, eating these annoying insects.
Even before the male akatu met the female, the beetle bird male was completely absorbed in courtship: he also sang for several days in a row. The trill of this bird is not particularly difficult and is similar to the monotonous voice of a cricket. Beetle birds are much more numerous than akatu, therefore, two or three days after the start of mating calls, the beetle bird male acquired several females. These birds immediately began to carry dry grass and build nests at the base of the akatu’s nest. The male, on whose territory they settled, from time to time helped them with the construction of their nests, but for the most part he was engaged in the protection of the territory from rivals. In the mating season, the beetle bird male becomes very cocky: he attacks other males appeared nearby, and does not give them the opportunity to “draw away” the female to them. Wherever he hears a voice similar to his own, he seeks the enemy. It happens that a beetle bird male attacks even crickets and grasshoppers that have settled nearby. The predator is safe for beetle birds and reliably protects them from enemies – birds of prey simply do not risk approaching akatu’s nest. Beetle birds female do not waste their time: they quickly gathered grass and made spherical nests among the branches at the base of akatu nest. This benefits the akatu: the building activity of the beetle birds strengthens the predator’s nest.
By the time a female appeared in the nest of the akatu, chicks were already squeaking in the nests of the beetle birds, and their mothers were catching insects among the vines and over the nest of the akatu. Occasionally, the beetle bird male helps the females to feed their offspring, visiting their nests one after another, but he prefers to engage in “foreign policy”, protecting the territory.
In the nests of beetle birds, there are 2-3 eggs, and when the clutch is lost, the bird easily makes a new one. In contrast, akatu often has only one egg in its clutch, and if it falls out of the nest, is broken or turns out to be unfertilized, the birds no longer nest this season. The female treats the egg as the greatest treasure: she hides a freshly laid egg under her body, and does not allow the male to approach it for a long time. When the male gets too close to her, the female hisses and clicks with her beak, warning him about her displeasure. But this only lasts for a few days. The male feeds the female, and her aggressiveness softens gradually.
Later, the female already trusts the male to incubate the egg and flies away from the nest – she needs to maintain her physical shape and needs to care for the plumage. The female takes dust baths and baths in shallow lakes near the rocks where the nest is located. In the akatu family, there is a certain division of responsibilities – while incubating an egg, the female spends more time at the nest, and the male carries food to her: small animals swallowed whole, and pieces of meat of large prey. The birds do not care too much about the cleanliness in the nest: some pieces of meat fall through the loose litter and begin to rot, attracting flocks of flies. Insects lay eggs on the remains of akatu prey, and soon their fat white maggots crawl in the thickness of the nest. Akatus are oblivious to these little things, but their neighbors, the beetle birds, are very interested in the uninvited guests. They deftly scurry between thick branches, of which the base of the akatu nest is made, and peck larvae from the remains of food of the akatu and from the litter of the nest. This food is easy to get for them, but the birds should be careful: the hatching female can simply peck and eat them.
Akatu male and female express signs of affection to each other: returning from the hunt, the male gently touches the beak of the incubating female before regurgitating a portion of meat. The egg even more strengthens the bonds of partners: it becomes the center of their universe, and determines the relationship of the birds. Only acting in common, a pair of akatu is able to hatch and raise a chick successfully.
Sometimes the shadows of the past return. Last year was unsuccessful for the akatu male: the chick died and the couple broke up. But one day this past came back. When the female akatu incubated the egg, and the male was busy with the hunt, the silhouette of a huge bird appeared over the mountain plateau. The female akatu recognizes her partner from afar by the features of the flight, and she sees that the bird approaching the nest is not her mate. It is not even a male, but a completely alien female. More precisely, this female is not familiar to her, but the male, if he was near, would certainly recognize her: this is the female that nested here last year. She hopes to continue the relationship with the male, but it looks like she is late hopelessly. The nesting season has already begun long ago, and a third of the long incubation of the egg has already passed: the time is hopelessly lost. Moreover, the male already has a pair.
The lawful owner of the nest meets the unknown female on approach to the nest – during the incubation, she perceives the approach of an unfamiliar congener as a sign of aggression. The alien female clearly did not expect such a turn of events, and was confused when another bird flew up to meet her with a warning cry. The owner of the nest shows with all her might that she is ready to defend the right to motherhood at any cost, and at that moment her rival made a fatal mistake, the cause of which was her hereditary increased aggressiveness. Instead of turning around and flying away, she pounced on the owner of the nest, and a battle of giants began in the air. The heavy birds find it difficult to perform aerobatics, so even in the air they expect to win with brute force. Two females fly trying to rise above the opponent and kick her on the back. They scream loudly and beat each other on the head with their wings. Akatu flight feathers have very hard shafts, so the blows are strong and unpleasant. The fight, with some breaks, lasts about two hours, and is very exhausting for the birds. When they rest, the owner of the nest hurries to the precious egg, and her rival rests on the ledge not far from the nest. The two resting females see each other, and this further increases their aggressiveness towards each other. It is difficult to say how long the fight of these birds could have lasted if the male had not returned. He successfully hunted in the plains, and returned with several pieces of meat in his gorge. It is difficult for him to fly, but the sight of two birds fighting near his nest gave him strength and determination. A few more powerful flaps of his wings, and he burst into air combat. The pair jointly protects the nest and the egg from the lonely female, and she will not be able to stand alone against two birds, even with her strength and aggressiveness. The lonely female flies away, and the female owning the nest chases her for some time, kicks her on the back and screams. That lonely female will no longer be able to nest this year – she lost time, and there is no single male left in the vicinity. Perhaps she would be lucky next year – akatus live long and are able to nest for several decades. She flies away from the territory of the akatu pair, and will not return here. The male and female return to the nest together, and she immediately covers the egg with her body and gently rolls it under her side by the beak. The male begins to regurgitate pieces of meat and gives them to the female from beak to another. After the meal, the female permits the male to be closer to the precious egg, and he takes a seat next to her. The birds gently touch each other’s feathers with their beaks, and the male begins to gently cleanse the skin near the eyes of the female – it is the top degree of confidence in these predators.
Clouds gather in the afternoon. The sky turns overcast and a cool wind blows from the Atlantic Ocean. It brings a relief to nature: it gets colder a little bit, and the inhabitants of the South American plains hide in shelters. The clouds become more and more numerous, and soon they merge into a single veil, behind which the sun is hidden. In the northeast, lightnings strike the sky, and soon thunderbolts are heard over the Gran Chaco. Then raindrops pound on the ground, damping dust down and turning clay into mud. The rain intensifies from hour, and falls throughout the evening and most of the night. The water flows down the stone cornice, and it is rather dry in the nest of the akatu – only sometimes gusts of wind shower the birds with rain. In bad weather, even a beetle bird male stopped its annoying trill, and hid in one of the nests made by his numerous “mates for life”… only for one season.
The beginning of the rainy season is a time of plenty for most of the inhabitants of the South American plains. After a good rain, the rhizomes of plants, which have been in torpor for several months, wake up and the plains become overgrown with fresh lush vegetation in a few days. Young foliage begins to grow on the trees, and some of them immediately begin to bloom, arranging bright accents in the palette of green shades of the plain landscape.
Leaves and grass represent the food of the many herbivorous mammals that inhabit the area. The Gran Chaco is home to some of the largest mammals in South America during the Neocene. Among them, tapirotherium, one of the last odd-toed ungulates, is remarkable with its unusual appearance. Having survived in the inaccessible remnants of the forests of South America, the ancestors of this mammal turned into an unusual animal, remotely resembling elephants of the Holocene epoch. Huge animals, reaching four meters in length and two meters at the shoulders, roam the Gran Chaco in herds numbering dozens of individuals. Their bodies are covered with dark brown hair, and against such background the mobile cross-striped trunk is well visible. With the help of their trunks, animals communicate: the trunk allows them to emit a wide range of sounds, and its position expresses the mood of the animal. Tapirotherium herds are in constant motion – staying somewhere for a long time, they could destroy all vegetation, like elephants once did in Africa. It seems that the tapirotheres are very happy with the beginning of the rainy season: they wander with great pleasure in the pouring rain. When the trees begin to cover with fresh foliage, tapirotheres feast on fresh growth: they break branches with their trunks and put them in their mouths, and some gourmands stand on their hind legs, leaning on the tree trunk and reaching with their trunk to the juicy leaflets inaccessible to most inhabitants of the Gran Chaco.
Tapirotheres are very fond of water: these animals have a great need for drinking water, and in drought they did not go far from drying up rivers. In hot weather, these animals love to swim and wallow for a long time on the sandy riverbank, peeling off parasites from their skins. Where tapyroteria take sand baths, deep pits form on the sloping bank of the river. When a herd of tapirotheres approaches one of such places, the animals are seized with excitement: they noticeably accelerate their pace, hoping to occupy a deeper hole. Water seeps at the bottom of some of the pits, and such places are especially loved by tapyroterias. They quickly take up sandy baths and begin to throw sand over themselves with their feet and trunk. The old female, the leader of the herd, unceremoniously drives out the young female from the pit she likes, and lies down in the cool sand. She has been leading a herd for many years and has earned a better place for herself. Several young tapirotheres did not get personal sand pits, and they decided to frolic in the water. Juveniles enter shallow water, scaring away schools of small fish, and splash, raising clouds of silt from the bottom. Like elephants, young tapirotheres pour water on their bodies from their trunks. This skill is very useful for them, especially in a drought: a large animal suffers greatly from the heat and it is especially important for it to be able to cool down.
When a flat head with small eyes and wide mobile nostrils appeared from under water, the frightened young tapirotheres ran ashore. An animal gets out to the shore, shaking its small ears and snorting. Long, bushy whiskers and two pairs of large white incisors indicate that it is a rodent. But what a rodent is it! In size, this animal is only slightly inferior to tapirotherium, although in weight it may well compete with it. It is barocavia – the largest rodent on Earth in the Neocene epoch. Having sniffed the air, the barocavia indifferently passes by the tapirotheres, resting on the shore, and goes into the tall reeds. Among the stalks of giant marsh plants, its relatives graze, tamping and devouring juicy greens with crunching. Being next to these giants, you can almost not be afraid of an attack of a large predator. Therefore, next to the barocavias, their smaller relatives feed – giant pacas, pig-sized rodents with armored cheeks, of brown color with white spots on the rump. These animals keep in one common herd and are not afraid of ground predators. From time to time, the barocavias, having eaten their fill, enter the water and dive. They swim several meters under water, touching the bottom only with the tips of hoof-like claws, and emerge in the middle of the river, where the current has washed over a small sandbank. Giant pacas do not swim so far from the shore, and go into the water only up to shoulder depth. They are always on the lookout and must be wary of other animals: a monstrous tyrannocharax fish with powerful jaws and sharp teeth is found in the river. Tyrannocharax reaches about four meters in length and is remarkable in its ferocity – it is a monster, whose presence must be reckoned with by everyone who is smaller and weaker than this one, and sometimes even larger animals are not immune from its spontaneous and violent attacks. Usually the fish hides in shallow waters and waits for prey, frozen at the bottom motionlessly. Tyrannocharax eats everything from turtles and fish to giant pacas and young barocavias. In the hot season, when the oxygen content in the water is low, the presence of tyrannocharax is easy to detect from afar – the fish from time to time emerges for a portion of air, inhaling it with the help of a swim bladder, which performs the function of a lung. At this moment, a hoarse sound is heard over the water. Hearing it, the animals on the shore rush to leave this place as soon as possible. But they are calm: at such a moment the tyrannocharax does not hunt. But when the fish does not appear at the surface for too long, it is much more frightening. Tyrannocharaxes replace crocodiles in the rivers of the tropical region of South America.
The male akatu, flying over the river, sees more than animals on land. The herd of tapirotheres resting in the sand looks tempting, but in fact it is completely out of reach for the feathered predator – these animals are too strong and it is very easy for them to crush the akatu into a cake. Barocavias are stupid, and there are some cubs among them, that can be attacked. Akatu has experience in attacking these animals, but now they graze among the plants, where the akatu with its huge wings will be simply helpless. From a height of its flight, the akatu male sees in the river silhouettes of frightening fish sliding in shallow water and waiting for an inexperienced or weak animal to be away from the rest. The akatu male not only hunts: he lives his habitual life, and hunting is only a part of it. He enjoys teasing tyrannocharaxes. To do this, it descends and quickly flies over the very surface of the reservoir. Frightened by his shadow, the large tyrannocharax abruptly rushes to the side and huddles into the reeds, convulsively hitting its tail and raising a cloud of silt and rotting plants from the bottom.
The akatu male appeared near the river for a reason: it is more likely to find prey here. Satisfied with the spectacle of the fearful fish in panic, the akatu male flies up and circles over the river valley. Its eyes and nostrils work together to enhance the hunting efficiency of the bird. Among the many smells of the ground, carried by the ascending air currents, the bird clearly distinguishes the smell of blood that is desired for it. Apparently the tyrannocharax recently wounded a young barocavia, and its wound is still bleeding. The bird of prey instantly reacts to the smell, and begins losing height. The akatu male flies over a herd of barocavias, trying to identify the wounded animal and assess the possibility of an attack. When it flies too low over the herd, several adult animals raise their heads and roar, baring their sharp incisors and trying to drive off the akatu male. But these threats have little effect over the akatu male: he knows from his own experience that in barocavia herds each animal protects only itself, and only the female takes care of the cubs. But adolescents are the most convenient targets for attack: they are still too weak to defend themselves against the akatu, but their parents no longer care about them. Having flown over the herd of barocavias once again, the akatu male definitely detected his future prey: a juvenile barocavia, with a piece of skin hanging on its shoulder – its skin is ripped open by the sharp teeth of a tyrannocharax. The young barocavia managed to escape from this fish, but now the blood attracted another predator – the akatu.
Akatu is not able to attack barokavias from the air – for this purpose, its claws are too thick and blunt. Therefore, the bird begins to chase the herd of barocavias along the ground. The akatu male lands not far from the herd and approaches the animals, walking on his strong legs. The wounded barocavia as if feels that the bird wants to attack it, so it tries to hide among adult animals. But adult barocavies are stupid and can be easily frightened with deceit. Approaching the herd, the akatu male stretches its wings and roars deafeningly with the help of the resonator sac on the throat. Such a “performance”, started unexpectedly, frightens the barocavias, and the herd gradually begins to move away from the bird of prey. When adult rodents move away from the akatu, the wounded animal appears exposed for a while. The male akatu does not waste its time and attacks it furiously: catches up and strikes with his beak at the side of the prey. When an adult beast turns towards him, the akatu male retreats just as quickly. He is cautious with reason – barocavia’s incisors are very sharp, and few land predators will dare to fight an adult barocavia one-on-one in an open battle. But the akatu is patient. The bird attacks its intended prey for a long time – within half an hour, the male akatu inflicts several more deep wounds on the wounded barocavia, and dark streaks of blood appear on the beast’s fur. The animal weakens with every minute, and the smell of blood scares off the adult barocavias from it. Gradually, the herd retreats, leaving the wounded congener alone with the predator. The akatu male continues its attacks, and soon the young barocavia falls on the ground, being exhausted from blood loss, and dies. The prey went to the predator.
In a world where many different predators live side by side, it is necessary not only to kill the prey, but also to be able to take advantage of it. Akatu hastily tears the skin of the giant rodent with his beak, and begins to peck out the meat and entrails of the prey. This bird will not be able to eat a lot of meat for a variety of reasons. A huge akatu is at the limit of the flying ability available to birds; therefore, having eaten too much meat, the bird may simply not take off. The second reason is that large prey attracts many freeloaders. A flock of hunting herons is hiding in the bush not far from the akatu hunting site. Seeing that the akatu had already begun to eat its prey, several birds grew bolder and decided to approach the carcass of the barocavia. For a while, the akatu is able to hold back the pressure of hungry hunting herons. When these birds get too close, akatu spreads his wings and screams loudly, scaring them away. The male gorges himself hastily: hunting herons are getting bolder, and sooner or later there will be too many of them here to be scared away. The akatu does not want to get involved in a fight with them: the slightest damage can deprive the male of the ability to fly. There is too much meat on the carcass of a young barocavia even for the large bird to eat everything, and some of it will certainly go to other carnivores.
Having swallowed a few more pieces, the male akatu moves away from the carcass, runs up against the wind, flaps its wings and takes off from the ground. He flies up and makes a large circle over the place of a successful hunt. The akatu sees how hunting herons gather around the carcass of the barocavia and begin to tear off pieces of meat. However, he sees a lot of things that the hunting herons, busy with feeding, do not notice. A shadow slides over the place where these flightless birds are feasting, and a giant akatu lands next to them, followed by another one. These birds have long felt the smell of blood, and gathered near the place of successful hunting, waiting for their turn. In the presence of winged giants, hunting herons do not feel too confident and retreat. Other akatus begin to tear the meat of the barocavia, occasionally giving each other sideways glances. After their feeding, on the carcass of the barocavia there will remain not too much meat, which hunting herons will be able to consume: these birds can not gnaw bones like carnivorous mammals do, and the most part of the meat rests after akatu feeding will be consumed by other carnivores.
The male actively delivers food to the hatching female. Perching on the edge of the nest, he regurgitates pieces of meat, swallowed after the successful barocavia hunting, and feeds them to the female. Flies are hovering around the male, being attracted by the smell of meat, and several beetle birds appear at once. Green-and-red birds deftly seize the insects, bothering huge akatus, and immediately rush to their nests, where hungry chicks await them. In akatu, more than half of the egg incubation period has already passed, and the female will need to incubate the egg not for too long. But at her a problem has exacerbated, that always accompanies any kind of living creatures – in the plumage of the bird parasites are established. While the female incubates the egg, she spends less time for herself, and parasitic insects actively reproduce in her plumage. The incubating female begins to scratch and shake herself, trying to make itch they cause to her go away in any way.
The plumage of the akatu is inhabited by several species of very small ticks. Some of them eat the dying upper layer of the epidermis, others settle in feather follicles, and still others simply suck the bird’s blood and hide under the feathers of the akatu. One of the specific parasites of this species is the goliath bird louse. This is the largest bird louse in the world – its length reaches 3 centimeters, which is quite a lot compared to most of the insects of this order, which do not exceed a few millimeters in length. This mobile insect clings to the feathers of akatu with short hook-shaped legs, and is additionally fixed between the feathers overlapping each other with the help of hooks growing in rows on its flat abdomen. Goliath bird louse gnaws at the feathers of a bird like how caterpillars do with plant leaves.
Once a day, the female akatu allows herself to leave the nest and swim in a shallow river at the foot of a mountain plateau where the pair’s nest is located. She gets up from the nest, gently rolls the egg away from the edge with its beak and lays a dried bush branch on it – this action will make the egg less noticeable to aerial predators. Having made few steps, the akatu female stops at the edge of the nest, opens her wings, and begins to stretch the muscles that have become numb after a long incubation. She stretches and then flaps her wings intensively for several minutes. Having refreshed herself, the akatu female takes into the air and flies down in circles to the ground, where the small river flows along the rocky bed. Without wasting her time, the bird enters the river and sits in the shallow water, spreading its wings slightly. She hastily takes a bath, shakes herself heavily, and steps out from the water. Water slightly cools the fervor of the numerous parasites. Some of them were simply washed away, and many ones had to seek shelter from the water on the back of the bird. The akatu female stops on the riverbank and shakes herself violently several times. The feathering of the bird is impregnated with water, so it flies back with difficulty. The sedentary lifestyle, which the female akatu led for the last weeks, also affected her condition: the bird rests halfway to the nest, standing on a small ledge of the rock. Having reached the nest, the female shakes herself at its edge once again, and continues to incubate the precious egg.
During the rainy season, the rivers of the Gran Chaco overflow their banks and flood the area around. In clear weather, the sun warms up shallow rivers, and various fish gather in deeper parts of channels, where the water is cooler and contains more oxygen. Flying over the rivers, the akatu male sees fish sides shining in the sunlight – schools of fish keep farther from the shore.
Where there is no water, dirt often remains, therefore, deermaras, swifl-footed cursorial rodents, leave to these places: they are not adapted to movement on swampy ground. On the contrary to them, sluggish semi-aquatic mammals enjoy an abundance of food during the rain season.
In hot weather, barocavias love to swim. These rodents inherited from their ancestor, capybara, the love for water, and spend there about half of their life on average. Barocavia herd grazes in the coastal vegetation from evening to morning, and after dawn goes into the river. When the rivers of the Gran Chaco flood in the rainy season, barocavias are in a time of abundance and enjoyment of life. It is a great pleasure for the huge rodents to stay in cool water in the heat of the day. These giant animals as if loose their weight in the water, and move gracefully, lightly touching the bottom of the river with the tips of hoof-like claws. When the barocavia is resting in the river, only the upper part of its flattened head with protruding eyes and nostrils appears above the water surface. In the mat of floating vegetation, swimming barocavia may escape from the sight of the predator watching from the riverbank.
Predators of the Gran Chaco are found not only on land, but also in the water – everyone coming to the river to swim or constantly living in the water should remember it and be careful. The splash and clatter of barocavia herd awakened a stagnated underwater predator. The body, covered with large scales with a mesh pattern, moved slightly. The dorsal fin of a huge fish opened as the dull stomp of barocavia feet sounded under the water. An adult tyrannocharax took a residency in this part of the river channel and hunted here for many months. This fish spent the dry season in a deep pool, which turned into a pond with dirty water at that time. In the drought, tyrannocharax ate all the fish trapped next to him. When there were no edible neighbors left, the predator caught ducks feeding on the surface of the water, and several times attacked the turtles, which tried to wait the drought in his pond. He survived this difficult time, and when a water’s great returned, the fish began to pretend to much larger prey than during the drought.
Tyrannocharax swims near the shallow water area, where barocavias are splashing. It is in no hurry to attack – large animals weigh much more than the fish itself. In addition, they are numerous, and they can simply drag the predator into shallow water and trample it. In the Holocene, African hippos did so when they attacked crocodiles and sharks. Barocavias are no less dangerous – one movement of their sharp white incisors can bite through the spine of tyrannocharax. Therefore, the fish is cautious, and carefully chooses its prey. There is a suitable prey in the herd of giant rodents – one young barocavia two months old is smaller and weaker than the other animals. It is young, and has not yet encountered the monsters of the rivers. This adolescent instinctively tries to stay close to large adults, but it makes a mistake at some point: the adult barocavia heads for the shore and the adolescent one appears exposed to attack. Tyrannocharax does not hesitate: the monster attacks the young barocavia with all possible fury. The sharp teeth of the tyrannocharax rip open the side of the young barocavia, and a cry of pain echoes over the water surface. When hearing it, adult barocavias begin to get out on the shore. The wounded Barocavia tries to do the same desperately, but it grows weaker by the minute. The water around it was already stained with blood, and the smell of blood excited the tyrannocharax. The huge fish snaps in the leg the beast trying to escape and drags it to the depths. Barocavia tries to free itself by striking the tyrannocharax with its hind paw, but the fish is able to suppress the prey’s resistance. Tyrannocharax drags the tearing itself away prey into the depths, and simply waits, keeping its teeth clenched. The movements of the caught animal become weaker, and air bubbles emerge from its mouth. A few minutes later, the barocavia chokes and dies. When the prey’s movements stopped, the fish unclenched its jaws, and the carcass of the young barocavia emerged to the surface of the water. Tyrannocharax has sharp cutting teeth, similar to those of a shark or piranha. The great fish begins to tear its prey, and even ripping open the thick skin of barocavia is not difficult for it. With its sharp teeth, tyrannocharax cuts off large pieces of flesh from the prey’s body and swallows them whole. He is not alone in the hope to eat well: a school of small fishes swims near the huge predator. While the tyrannocharax is eating, not a single fish longer than ten centimeters will swim up to its prey – the predator can simply diversify its dinner with it. However, predator just doesn’t pay attention to any small fry; therefore, pieces of its prey go to various small motley fish and water beetles that live in the rivers of the Gran Chaco. They are too small for the tyrannocharax to catch any of these creatures.
In the afternoon, the tattered and half-eaten barocavia body is already lying in shallow water. Several water beetles with shiny black elytra sit on it, and shrimps with long thin claws crawl in the water next to the remains of the rodent. Now, however, its scent attracts not only aquatic, but also terrestrial inhabitants. One of the inhabitants of Gran Chaco takes a special interest in the remains of the tattered barocavia. It cautiously comes out of the tall grass, stepping with its legs that have thick claws looking like hooves. This animal resembles a dwarf armored horse with a thick tail and short neck. Movable thin ears with blood vessels visible through skin twitch when the animal listens to surrounding sounds. This bush dweller is a donkey armadillo, an omnivorous local mammal. It eats a variety of foods – from berries and invertebrates to partly decomposed carrion. This edentate is distinguished by its amazing strength with a relatively small stature – a little more than half a meter. The donkey armadillo pulls the remains of the barocavia to the shore, hoping to eat well, but it only manages to move the carcass a little. Having tried several more times to pull the remains of the barocavia ashore, it simply enters the water and eats the meat, tearing off pieces with its small teeth. The donkey armadillo is well protected by its shell from the most part of predators, so it is among the first to eat up the remains of the prey of hunting herons and other predators. Sometimes donkey armadillo feeds on the prey of these birds, when the hunters themselves have not finished eating yet. He does not pay attention to the blows of their beaks and legs: these birds cannot cause it much harm. But its courage still has a limit: when the shadow of akatu male slid over it, the donkey armadillo ran away from the carcass and hid in the bushes. The akatu male landed next to the remains of the giant rodent and began to eat. He tears off the meat, which has just begun to deteriorate, and swallows it in large chunks. The male not only eats for himself, but also gathers food for the female, which is still hatching their only egg. But today, he will bring the female more than just food.
While the male was feeding on the barocavia meat, a small insect appeared in the air. It became very interested in the huge bird that was busy tearing the meat, not paying any attention to the world around it. The insect flew around the bird several times, choosing a place to land on it. This creature has a long abdomen, slightly drooping in flight, like a wasp. But, unlike wasps, this insect is not black and yellow, but black and red. Its wings produce a deep droning, also not similar to the buzzing of a wasp. In addition, the insect flies with the help of two hind wings, and the two front wings, which represent opaque, hard and shiny elytra, open to the sides and upward. The insect’s antennae also do not look like a wasp’s ones – they are feathery. Landing on the plumage of the akatu male, the insect neatly folds a pair of long wings under short elytra of bright red color, and hides among the feathers of the bird. This kind of insect is the predatory feather beetle. At first glance, this insect does not look like most beetles: its body is not round and stocky, but elongated and flexible. This is a representative of the rove beetle family. Feather beetles, as well as giant chewing lice, appeared in South America along with giant birds. The feather beetle is poisonous: its hemolymph contains acrid substances that make it inedible. And its color will be remembered for a long time by a predator risked attacking it.
Having climbed into the plumage of the akatu male, the feather beetle freezes, clinging to the feather. The huge bird tore off a few more pieces from the remains of the barocavia, hastily swallowed it, and moved away from the animal carcass. The male must hurry: the female is waiting for him in the nest. In the process of evolution, akatu has reached the maximum size possible for a flying bird. Therefore, every extra kilogram of swallowed meat can cause unnecessary difficulties for him when returning home. To take off, the akatu male must use a headwind. Standing up against the wind, the bird begins a run-up, flapping its wings. Having accelerated, the akatu makes several strong wing flaps, and takes off from the ground. The take-off is the most difficult part of the flight for this massive bird. Having found a powerful stream of rising air, the akatu can soar easily and effortlessly for hours, looking for food. The male has already found enough food for himself and for the female, which is waiting for him in the nest. Therefore, he goes straight to the rocky plateau, on the slope of which there is his nest.
When the huge bird got out of sight, the donkey armadillo got out of the bushes and continued to tear the meat of the dead barocavia. In the dry season, carrion makes up a significant part of the diet of this edentate, and in the rainy season it willingly eats plants. But at the right opportunity, this beast does not refuse food of animal origin.
The akatu male quickly reached the nest. The female greeted him with a welcoming click of her beak, and then gently took the belched piece of meat from his beak. While the huge birds exchanged greetings and the male fed the female, one uninvited guest began his life, hidden from prying eyes. Feeling that the male akatu is resting, the feather beetle hidden in its plumage, began to stir. The insect opened its sensitive feathery antennae, and began to turn its head, defining the smell desired for it. The feather beetle is attracted by parasites – huge goliath bird lice that have settled in the feathers of the akatu. It was the smell of these insects gnawing at the feathers of the akatu that attracted the beetle.
Possible prey items of the feather beetle, goliath bird lice cause a lot of harm to the akatu. They settle on body feathers, preferring places that are inaccessible for the bird’s beak. Usually this insect gnaws the feather barbs along the edge, like a caterpillar eating a leaf of a plant. When the akatu female, incubating the egg, shakes herself, the barbs of its feathers, gnawed by parasites, literally rain from her. Bird lice can crawl quickly, and their movement among the feathers makes the female akatu constantly scratch and shake herself. But in this way, she cannot get rid of annoying parasites. The activity of the goliath bird lice can be dangerous: if there are too many of them, they can easily damage the vanes of the flight feathers, which will impair the flight ability of the akatu. Therefore, the female, on which many goliath bird lice have bred, needs help. And this help came: at night, while the male akatu slept, pressed against the side of the female, a feather beetle crawled out of his plumage. After a little hesitation, the insect crawled onto the female and disappeared in her plumage.
The confrontation between predators and prey is very acute both in the world of giants and among dwarfs. The feather beetle is very small in comparison with the akatu, but is no less bloodthirsty and skillful in hunting. Akatu hunts on the plains stretching for many kilometers, and the insect feels as free and constitutionally among its feathers. The feather beetle starts hunting for the goliath bird lice. It climbs deftly in the plumage of the bird, wriggling and crawling into the tightest cracks. It is adapted to moving among akatu feathers as well as a bird louse. Sight does not help the feather beetle in hunting, but a keen sense of smell allows it to pursue the bird louse freely as in the open. The beetle follows the trail of the parasitic insect, moving its antennae. Goliath bird lice feel that they have an enemy: the parasites chased by the beetle are trying to flee. The pursued chewing louse escapes from the beetle among the feathers of the bird, wriggling like a worm. It helps itself to move, pushing off by the bristles growing on the sides of the abdominal segments. But the feather beetle inherited speed of movement from its ancestors, and easily catches up with its prey. The parasitic insect tries to hide from him under the wing of the akatu. The movement of insects on sensitive skin greatly disturbs the hatching akatu female: she jumps to her feet and shakes herself. A feather beetle falls out of its plumage, holding a wriggling bird louse in its mandibles. The pale and red-and-black insects curl up in one ball in their last fight. The goliath bird louse has no chance: its soft body wriggles helplessly in the strong mandibles of the feather beetle, and then hangs lifelessly, being bitten through. The beetle crawls into the litter of the akatu nest, where deals with its prey without disturbance, and then returns back to the akatu female’s plumage.
One beetle bird spots the feather beetle while it is hunting. These mobile little neighbors of akatu actively use the remains of the feathered giant’s prey, hunting flies that flock to the smell of a free treat. Having noticed a large insect flashing among the feathers of the akatu female, the beetle bird tries to catch it. The tiny bird carefully watches the feathers moving on the side of the akatu female, and then rushes with a piercing squeak and snatches the feather beetle. The insect caught by the bird opens its short elytra and shows a bright red spot hidden under them. The beetle bird did not let it go, and did not attach importance to this gesture of the insect, paying for it immediately: the beetle released a drop of acrid liquid, and its poison burned the mucous membranes in the bird’s mouth. Spitting out the insidious insect, the beetle bird perched on a vine, hanging from the stone ledge above the akatu’s nest, and began to sneeze squeakily. It will remember this lesson for a long time. And the feather beetle, neatly folded its wings under short elytra, climbed back into the plumage of the akatu female.
For the next few days, the akatu female, hatching the egg, is still shaking and cleaning itself, when the feather beetle crawls in its plumage in pursuit of parasites. On the other hand, she feels better and better: the predatory beetle has destroyed a significant part of the parasites. The feather beetle exterminated almost all adult goliath bird lice and many older larvae. When the amount of prey became too small for it, the beetle simply flew away. But it did not exterminate all the parasites: most of the larvae in the early stages of development managed to survive. They will grow up soon and the bird will need to be sanitized again. Even the most skillful predator will never destroy all its prey items, otherwise it will simply die of hunger.
The first brood of beetle birds has left the nests and flied away in the neighbourhood a long time ago. The male had time to perform his annoying trills again, and the females attracted by him are already hatching new clutches – the second generation since the beginning of wet season. And at this time, a long-awaited event takes place in the akatu’s nest, and both adult birds were waiting it. During the forty-first day of incubation, a muffled squeak began to be heard from the egg, and in the early morning on the forty-third day, the shell cracked from the inside, and a small hole appeared at the pointed end of the egg. Over the course of several hours, it expanded, and after the blows of a small weak beak from the inside of the egg, pieces fell off from the shell. Finally, at about noon, a large piece of shell broke off and a chick fell out of the egg. It is almost naked, blind and helpless. Without parental care, this creature would not have lived for several hours, but from the first minutes after birth, the chick can completely rely on the care and protection of the powerful akatu female. When the chick got out of the egg, the female threw accurately the shell into the depths of the rocky niche.
When the male returned from the daytime hunting, the female met him, clicking her beak, and the male landed with caution on the edge of the nest. The female continued hissing and clicking her beak, and the male decided to use the usual pacification technique – to share food with her. He regurgitated a piece of meat and gave it to the female, holding it with the tip of his beak. The female accepted this gift, but did not swallow it. When she got up from the nest, the male saw the reason for her aggressiveness – his own chick, a weak little creature. The female put the meat obtained from the male on the edge of the nest and tore off a small piece from it. Holding it in her beak, she touched the chick’s beak with the flesh. The small creature staggered, but stretched its head up and opened its beak. The female carefully put the meat into its beak, and the chick began to swallow the meat, twitching its neck. It swallowed two more little pieces and then lay on its belly. Only after that the female swallowed the remains of the meat and greeted the male, touching the skin near his eye with her beak.
With the arrival of the chick, the parental couple has more worries. Now the male must feed not only the female, but also the fast-growing chick, and the female carefully tears the meat brought by him, feeds the chick, and eats only after it is satisfied. At night, the akatu female carefully warms it, and in the daytime she protects the chick with her shadow from the hot sun.
Small beetle birds will have a second brood soon, and the pair of giant akatu successfully raises only one chick during the year, even if two eggs have been laid. Akatu’s chick development should be completed in the first half of the dry season as long as there is enough prey in nature. It should grow significantly by the time it leaves the nest: having been born with a weight of about one kilogram, it should gain weight about 60 kg by the time it leaves the nest. The care of its feeding falls on the shoulders of both parents.
At the age of one month, the body of the akatu chick is covered with gray juvenile down, through which the first true feathers begin to appeat. Until they are covered with sheaths, the young bird looks “prickly” – long feathers rolled to “needles” stick out from its wings and tail, on the back and nape. The chick’s head is completely covered with down. Now it is too weak to rise to its feet: the chick crawls along the nest, supporting on tarsi and rising to take food brought by the parents. On the back side of its tarsi, horny “calluses” develop, allowing the chick to move along the rigid inner part of the nest. At this age, the female helps it to cope with large prey, tearing it apart. But she already warms the chick much less, and occasionally leaves to hunt. She brings a variety of small prey to the chick, which she catches near the nest, and the chick swallows small animals whole. The male akatu still flies to hunt in the plains and attacks large animals, or looks for carrion.
When the chick was three months old, its appearance changed significantly: the feathers unfolded and cover its entire body now, and the remnants of the down on the back fall out. At this age, the head of a young akatu is already naked, but it does not have yet a blue spot on the throat characteristic for adult birds. The young akatu no longer needs heating, but requires a lot of food. Therefore, both adult birds spend most of their time hunting, supplying the offspring with meat. The chick has got stronger enough; it stands confidently on its feet and moves freely inside the nest. Its flight feathers have not fully unfolded yet, and it is not trying to fly for now. So far, the young akatu has only one concern – to grow well. The rain season continues; the conditions are still favorable for the numerous herbivores of the Gran Chaco, and the akatu chick does not lack food. Rain clouds gather in the afternoon, and by this time the parents usually return from the hunt. Young akatu can already eat on its own, and is able to tear apart large pieces of meat, pressing them with its foot to the nest. When there is a warm tropical rain, adult birds and their chick take refuge in the nest. But a young bird sometimes leaves its parents and takes a bath: it goes to the edge of the nest and stands for some time, being fluffed up, under the streams of rain that fall there with the wind. After wetting the plumage, the young bird shakes itself, then moves deeper into the rocky niche and dries. Goliath bird lice have settled in the plumage of young akatu a long time ago, and sometimes feather beetles, attracted by the smell of parasitic insects, visit the nest, being brought there in the feathers of adult birds.
While the akatu chick is growing up, the beetle birds, small neighbors of the huge feathered predators, managed to breed for the third time, and the male finally stopped his annoying mating calls until the next rain season. Fledglings of beetle birds, hatched in woven grass nests made right under the akatu dwelling, began to appear near the akatu nest. They differ in color noticeably from adults: the young bird has brown juvenile plumage without the characteristic metallic sheen and characteristic “eyebrows” above the eyes. Fledglings of beetle birds fly badly, and can only flip from one branch to another. They wait for their parents, which finish their feeding for a few more days, perching on vines and creepers stretching along the rock. But one fledgling took off from the parental nest, and got directly into the akatu’s nest. Adult akatus would not have paid attention to him, but their chick became interested in this little guest and began to observe it attentively. An inexperienced beetle bird fledgling does not even imagine what kind of danger it is exposed to, moving frivolously along the nest, where the chick of a bird of prey sits. While the akatu chick does not move, the fledgling of the beetle bird does not feel the danger coming from it. The small bird flips over the nest, peeks between the branches of which the nest is made, looking for insects. It is gradually approaching the akatu chick, frozen in waiting. When it fluttered again, a strong beak blow killed him on the spot. The akatu chick pecked at it as easily as the fledgling of the beetle bird itself pecked at the flies. It snatched the lifeless body of the small bird with its beak, and swallowed it whole. This event, ended fatally for the beetle bird, is a good sign for the young akatu: the chick can grow up to be a skillful hunter. But it still has a lot to learn.
The wet season has come to an end. The rainfall decreases, and sometimes rain does not fall for several days in a row. There is still enough moisture in the soil, and the vegetation is still sparkling with all shades of fresh greenery. The rivers are still full-flowing, and many inhabitants of the Gran Chaco come to their banks to drink. But in the coming months, tests for all animals and plants will inevitably begin. About six months have passed since the akatu chick hatched. The young bird is strikingly different from the naked and helpless creature it was in the first day of its life. The young akatu is fully fledged now, and its throat gradually aquires a bluish tint. After a few months, the throat of the young bird will turn bright blue, like that of an adult. It will mean that the young individual has become independent, but it will also be a sign that its parents and other adult akatus will no longer treat a young bird as tenderly as a chick. The plumage of juvenile akatu is still dimmer, rather that at adults. The young bird has reached about 60% of the weight of an adult, and the flight feathers on its wings have fully developed. To fly well, the young akatu trains for a long time: it flaps its wings and jumps for hours. At first, attempts at takeoff are unsuccessful, but gradually the training yields a result: the bird manages to break away from the nest and hold out in the air for several minutes, flapping its wings fiercely. Emboldened by its success, the akatu continues its training. Another week passes, and the young akatu decides to take its first flight. It stands at the edge of the nest, spreads its wings, and uncertainly changes from foot to foot, not daring to take off. As if for the first time, the akatu spreads its wings and flaps them. High altitude both attracts and scares it away. Previously, the akatu trained while standing in the nest, and could fold its wings, lay down and have a rest at any time. But real flight is a more complex and dangerous endeavor. Finally, the young akatu decisively breaks off the edge of the nest, and makes several flaps of its wings. It is not confident in the air, and the first flight does not last long – it continues only a few minutes. The bird makes a small circle over the rocks, and quickly returns to the nest. The first flight turned out to be rather tiring: the young akatu lay down on the bottom of the nest and stretched out its legs, breathing heavily. The rest of the bird was interrupted by the parents returned from the hunt, and the young bird began to peck greedily at the meat they regurgitated.
Being encouraged by the first success, the young bird trains longer and longer every new day. New flights take place further and further from the nest, and a new and previously unknown air world gradually opens up to the young birds. Akatu learns how to search and to catch updrafts, and to use them to stay in the air without sparing effort. Hot weather is very favorable for flight lessons: during the day, steady updrafts appear over the rocks, and the young akatu learns to soar. Having made a circle over the rocks, the bird got into a powerful stream, which literally carried the young akatu over the plateau. The splendor of the Gran Chaco opened up to the eyes of a bird: a forest on the top of a mountain plateau, vast plains, and in the distance, in the haze of heated air, some more mountain plateaus of the same kind. Young akatu tries not to lose sight of its native nest, therefore it does not move away from home. It makes one more circle in the air, and descends to the edge of the rock, under which there is the nest, where this bird saw for the first time the light.
The young akatu looks around: from the top of the cliff, the surroundings can be seen much better than from the nest. The bird looks around with curiosity the unfamiliar world that has opened up to it, and notices two small, but well-known silhouettes in the sky. These are its parents returning from hunting in the plains. They approach, and the young bird sees them clearer and clearer. When the mother and father flew even closer, the young bird began to call loudly to them right from the top of the plateau. The adult akatus recognized the voice of their chick, and hurried to the nest – they got used to the fact that the chick’s voice came from there. Approaching the nest, they did not see their offspring there. Instead of it, there was a bird standing right above the nest, which they had not seen before. The adult akatus decided to find out who is this stranger and flew to the top together. Seeing them, the unfamiliar bird stretched its wings a little bit, slightly squatted, and... screamed with a long-familiar voice, begging for food from the parents. The chick has grown up and is learning to fly. The usual order of things has changed again, but this is quite natural.
The young bird learns to fly, and every day it achieves an increasing success. It becomes more and more difficult for parents to find their offspring after a successful hunt – the young akatu constantly leaves the nest, exploring the surroundings, and sometimes meets the parents already in the air. And once a day comes when the young bird no longer remains in the nest, when the parents fly to hunt. The young akatu leaves a cozy and safe world – a nest built on the rock inaccessible to predators. To become a top predator of the Gran Chaco, this bird must get to know the inhabitants of this world, and learn how to behave correctly in their presence.
During the flight, the young bird tries to copy the behavior of the adult akatus, and keeps closer to them. The brain of the akatu is overflowing with new sensations, which the young bird has yet to learn to understand. Sharp eyesight and sensitive sense of smell – these are the qualities, which help adult birds to search for food. Young Akatu learns to establish a connection between sensations and events. Among the many smells of the ground heated by the sun, the smells of drying swamp mud and blood stand out: near a drying lake, a lonely hunter heron feeds on the corpse of a giant paca. The bird managed to ambush this rodent when it got out of the swamp, and killed it with a well-aimed blow of its beak in the eye. It seems that the hunting heron will not be able to take advantage of the result of its own hunt: three huge akatus descend into the grass next to it. The hunting heron tries to display its power: it makes several aggressive attacks towards the akatu, and snaps its beak equipped with tooth-like outgrowths along its edges. However, the forces are too unequal: any of the adult akatus is larger than the hunting heron. Adult akatus display their strength and excellent physical shape: they open their huge wings and make an attack on the heron, uttering loud trumpet sounds. The young bird hesitates for a few seconds, but notices that the hunting heron is frightened. Then the young akatu joins its parents, imitating their postures and movements. In this way it learns to take away prey from other predators, and the first lesson is successful: the hunting heron retreats, leaving the prey to the akatu family. Large birds surround the corpse of the giant paca and eat the meat together. For adult birds, this is a very common event, and the young akatu eats meat of a large prey directly for the first time – before that it received it in pieces from the beak of one of its parents. The young bird recalls how it tore up large pieces of meat, belched up by parents returned from hunting, and tries to do the same with the carcass of the giant paca: holding the animal’s corpse with one leg, it pulls out small pieces of meat and swallows them. In addition, the young akatu for the first time feels the natural taste of meat – before this moment it ate only the meat regurgitated by adult birds. If this bird will manage to live successfully the first years of life, it will know a lot about the taste of meat. During the fodder shortage periods, akatu eats meat that has already begun to decompose without harm to itself – acidic gastric juice suppresses successfully the activity of bacteria that multiply in rotting meat. In drought, the akatu can gather fish appeared in holes with water in the river bed, and not able to escape. At this time, even young tyrannocharaxes can fall prey to akatu. In any season, akatu can attack large animals of the Gran Chaco, and can defend prey in the face of other predators. However, while the bird is young, it has to rely on parental care and learn to be independent.
Akatu is a strong and aggressive bird. But sometimes these qualities are not enough to survive in a world where even larger and stronger animals exist. And then prudent retreat and simple caution turn out to be more important for survival than the killing prowess.
Neocene South America is inhabited by a large number of endemic large animals. The descendants of relatively small species of the human epoch evolved actively in stable and favorable conditions, and in Neocene herds of giants roam the plains of this continent. Among the characteristic inhabitants of the plains there are giant beasts tapirotheres, similar to the Neogene mastodons. Huge animals, covered with short brown wool, wander across the plain. The legs of these animals, equipped with massive hooves, trample the bushes and crush the trunks of young trees. Tapirotheres are the largest animals in this area, and they may not be afraid of predators. The trunk is the most remarkable feature of this beast. With its help, tapirotheres pluck branches on the go or pull out bundles of grass from the ground, and put them into the mouth. Sometimes animals stop near bushes, eating young shoots. Like elephants, tapirotheres thin out bushes and prevent woody vegetation from forming of continuous stands. Due to them, the Gran Chaco represents a “patchwork” of plains and forest areas, where not only the inhabitants of forests and shrubs can exist, but also the swift-footed inhabitants of the plains.
A donkey armadillo runs alongside the giants, in the clouds of dust raised by their feet. The manner of movement of this edentate one is very funny – the donkey armadillo quickly minces with its strong legs, and its thick claws as if beat a roll of drums against the ground. Although this animal is well protected from most predators of the plains by its shell, it prefers to stay close to giants – it is much safer this way. When the tapirotheres stop near the bushes and begin browsing branches, the donkey armadillo sets up a hunt for various small animals, frightened by them. It is agile enough to trample and eat a lizard, and insensitivity to poisons allows it to eat even poisonous beetles, crunching their shells. When the tapirotheres, breaking the branches of the bush, scared a little bird nesting in them, its nest and clutch became immediately the prey of a donkey armadillo. This omnivorous creature is perfectly adapted to life on the plains, and never lacks food.
After eating the bush, tapirotheres continued their way. At the beginning of the dry season, they congregate near the deep rivers in the south – it is not so hot there, and there sources of drinking water always exist. Tapirotheres need a lot of water, and their cubs are especially sensitive to a lack of it. If the female suffers from thirst, she stops producing milk, and the cub may die of hunger. Therefore, these animals make annual transitions to sources of water, or wait out drought in areas, where a sufficiently large amount of water has kept in river beds.
During the migration, tapirotheres are especially cautious and mistrustful. They are ready to attack any animal that they consider dangerous to themselves. Therefore, when they spot the akatu family eating the corpse of the giant paca, the herd becomes agitated. Tapirotheres see birds, which are instinctively connected in their subconscious with a sense of danger, and also smell blood. As long as these giants are healthy and strong, they do not pay attention to akatu birds. But now the situation is completely different: in this herd of tapirotheres there are cubs born in the last rainy season, and the herd is migrating. Tapirotherium cubs differ from adults not only in smaller size, but also in the absence of cross stripes on the trunk. Their presence makes adult animals more aggressive, so the adult animals of the herd display immediately threatening postures to predators. The animals raise their trunks and trumpet, exhale with efforts, shake their heads and stamp their feet – these actions unambiguously express their readiness to attack. Akatus retreat – all three birds weigh much less than any of the adult giants of the plains, and in the case of a fight, they will simply be trampled if they will not manage to take off. The young akatu does not yet understand that not all animals can be driven away by a threatening display. It is trying to repeat the same trick that it performed about half an hour ago, when its family chased the hunting heron away from the prey. The young bird turns to the approaching tapirotherium herd and spreads its wings wide. In response to it, the adult tapirotherium female, leading the herd, rushes suddenly at the birds, showing agility surprising for its size. Several more animals rush after her, and the ground hums with their stomping. The family of akatu is forced to flee: adult birds run away from the carcass of the giant paca, followed by a young akatu. They accelerate, flap their wings and take off in unison.
Having driven akatus away from the prey, tapirotheres bypass the animal’s corpse. They utter disturbing sounds and fearfully look sideways at the carcass of giant paca pecked by birds and emitting a frightening smell of blood. Tapirotherium cubs, not understanding yet what the adults are afraid of, remember the smell of blood and the disturbance of adult animals. Having heard the anxious voices of females, cubs try to keep closer to them. They will also remember the silhouettes of huge birds that hover in circles over the herd, and they will also begin to associate their presence with danger.
The first day of a young akatu outside of its native nest ends. The sun is setting, and the birds must have time to use the rising currents of warm air to return home. The young bird has received enough survival lessons today, and now it needs to have a rest. A few more days will pass, and the whole akatu family will leave their nest. They will begin to wander over the vast feeding territory of the parental pair. Young bird is rather slowly learning, and it will depend on the hunting success of its parents for several months, making its own contribution to it. It will feed with adult birds and learn to live in the world of mountains and plains. But shortly before the new nesting season, the parents will drive the young akatu from their territory, and the bird will have to look for a new place to live. Being lucky in this difficult task, and having managed to form a family, the young bird will become one of the winged lords of Gran Chaco and will be able to live for quite a long time – more than half a century. It will continue so from generation to generation, while the forces of nature are dormant, and the habitat of giant predators is stable.

Akatu (Sciopterornis acatou)
Order: Cathartiforms (Cathartiformes)
Family: Cathartids (Cathartidae)
Habitat: Andes, plateaus and adjacent plain areas.

Picture by Amplion, colorization by Biologist

In the legends of the Indians of South America, Akatu is the mother of king vultures, a monstrous twelve-headed bird. In the Neocene epoch, a creature appeared in the ecosystems of South America, which can compare with this mythical bird in strength and greatness. It looks less monstrous, but no less impressive than its legendary prototype.
In the epoch of the global ecological crisis, only a few species of birds of prey managed to survive. Most of the feathered predators experienced hard times in the human era: the destruction of habitats, extermination and disturbance led to the fact that the ranges and numbers of many species, especially large ones, decreased in great degree. Only a few flesh-eating birds have mastered life next to humans. Among them, there were “false” birds of prey – cathartids, more akin to storks. One of their representatives, turkey vulture (Cathartes aura), achieved particular success in the struggle for existence. It has retained a high abundance and a wide range in anthropogenic landscapes. After the human extinction, this bird began to master the deserted lands, and began to evolve actively. One of the descendants of this species has completely lost an ability to fly, but another one kept this ability and began to adapt to feeding on large carrion. In the Neocene, this line of evolution gave rise to a monstrous creature, the largest flying bird of the Neocene epoch, akatu.
Akatu is much larger than its ancestor: the weight of an adult bird is about 100 kg. Males of this species are smaller than females – they reach a weight of 70-75 kg only. The growth of an adult female reaches 2 meters, and the span of wide wings is up to 6 meters. The name of the bird in Latin means “bird shading with its wings”. The flight feathers of this bird reach enormous sizes: their length is up to 75 cm at the width of about 40 cm. The wings of the akatu are wide, with rounded tips – bird is able to soar at high altitudes for many hours. Such large flying birds are very rare in nature. Teratornis (Argentavis magnificens), known from the Tertiary period, reached similar size. In Neocene, when productive stable ecosystems became widespread, giant feathered predators returned to Earth in the form of akatu.
The growth of the akatu is determined mostly by the proportions of this bird. Akatu’s legs are very long and muscular – if necessary, the bird can run quickly on the ground. Most often, this is needed to build up speed during takeoff. But sometimes akatu falls a hostage to its own appetite: having found a rich source of food (for example, a large carcass of an animal or the remains of the prey of large predators), the bird eats so much that it cannot take off immediately, and has to spend some time on the ground. This circumstance may be fraught with significant dangers: on the plains and in the foothills of South America there are large predators – jagueira and hunting heron. However, in case of emergency, akatu can regurgitate some of the meat eaten and fly up.
The akatu's appearance is inherited from its scavenger ancestor, and a number of “family traits” of the turkey vulture have been retained. The head and front of the neck of akatu lack feathers – it is an adaptation for feeding on carrion. The skin of the akatu’s head is very brightly colored, as befits a living embodiment of the legendary bird: the crown and sides of the head are reddish-brown, the throat is bright blue. The skin on the head and throat is smooth, but large, warty outgrowths of orange color develop around the eyes. They are especially noticeable in males. During the courtship ritual, these outgrowths swell greatly from the inflow of blood and become even brighter.
Akatu’s beak is very long, and the corneous cover is developed only in its last third. It forms a large corneous hook, which can easily tear meat apart. Akatu’s elongated nostrils are located in the middle of the beak; they can be colosed by a special fold of skin when the bird tears food with its beak. Akatu’s sense of smell is very acute – this is a common feature of cathartids, which has received a special development in this species. Hovering in updrafts over the plains, akatu is often guided by smell in search of food. The akatu’s sense of smell is especially sensitive to fresh blood, so these huge birds soon appear near feasting predators or scavengers. They can control a vast territory and are easily get enough food from the remains of predators’ meals. The vision of this bird is very sharp.
On the male’s throat, an “wattle” grows – a special outgrowth of the trachea, which serves as a resonator. From outside, “wattle” is covered with feathers. The voice of an adult male akatu is similar to the siren wailing; the “wattle” is swollen at this moment.
Akatu eats meat of large animals – giant paca, barocavia, tapirotherium – but is very unassuming in its choice of food: this bird will willingly eat even the meat that has begun to decompose. Sometimes this bird can find large fish in the water bodies drying up after flood. In search of prey, akatu can fly about a hundred kilometers in a day. Usually this bird does not attack healthy animals, but chooses already sick or dying ones. This giant predator chases such individuals at a foot’s pace, sometimes for several hours on end. From time to time, the bird attacks the weakened animal, inflicting wounds on it with its beak. Often several more congeners join one bird, and the hunt becomes even faster and ruthless. Akatu usually eats the soft parts of the carcass, and the remains of the meat on the bones go to a variety of small inhabitants of the savannah. Often akatu appropriates prey of land-dwelling predatory birds, using its indisputable advantage in body size.
Akatu feeds on plains, but hatches chicks on mountain ledges protected from predators. The distance between a bird’s nest and its feeding grounds can make tens of kilometers, but for a well-flying bird this is not an obstacle at all. The development of akatu chick takes a very long time, so courtship rituals in these birds are performed quite early: at the end of the drought season. Usually the male begins courtship: he flies over the place chosen for nesting, attracting the female with loud calls. However, usually this ritual is a purely formality: in most cases, a pair of these birds forms for life. Out of nesting, mates can spend time in different parts of the common territory, but during the rearing of offspring, the pair is reunited.
Soon after the formation of a new pair, or after the family reunion, a nest renovation begins. Akatu’s nest represents a huge construction made of twigs and branches, lined with dry grass taken from the plain. It is built by both parents, but the male takes responsibility for finding building materials, and the female itself builds or repairs the nest. For the construction of the nest, a niche in the rock is chosen, if possible protected from the wind and the midday sun. The nest can exist for many years, sometimes being passed from generation to generation. Akatu nests can exist in the same place for up to two hundred years.
There is only one egg in a clutch of akatu. Extremely rarely, and only the strongest females can lay two eggs, but in a year poor in food, as well as in young or old birds, there is only one egg in a clutch. The chick hatches featherless, blind and helpless. It grows very slowly, feathering only in the fifth week of life. A young bird fully develops only at the age of about six months. At this time, the juvenile tries to fly, stretching its wings and jumping in the nest. About a week after the beginning of such training, the young akatu makes its first flight.
A bird of this species becomes an adult at the age of 4-5 years, but its life expectancy can be over 60 years.

Beetle bird (Superciliornis minutus)
Order: Passerines (Passeriformes)
Family: Cotingas (Cotingidae)
Habitat: South America, Grand Chaco.

Picture by Amplion

For South America of the Holocene epoch, birds of the suborder of suboscine passerines (Tyranni, or Suboscines) were very characteristic. They were typical forest dwellers, and achieved great diversity in rain forests. Birds of this group settled into the mountains, reaching the temperate mountain zone of shrubby vegetation. During the Ice Age, when forest areas began to decline, the abundance and species diversity of suboscine passerines decreased. From numerous families, only a few relict species survived, preserved in islets of once-extended forests along rivers and on foggy mountain plateaus. Later, when the forests again spread over the northern part of South America, the process of active dispersal and speciation of these birds began. However, some of them have not left their usual habitats. On the mountain plateaus of the Gran Chaco towering among the vast plains, some bird species have survived, descending directly from the relics of the Holocene epoch. One of them is a tiny but amazingly bright beetle bird.
It is a very small bird: its body length is about 10 cm, including the tail. Beetle bird has a large head, short and wide tail, and wings rounded at the tips. This physique determined the name of the bird: it moves slowly, somewhat resembling a huge beetle. This bird flies reluctantly and prefers to look for food among branches and creepers.
The body is coloured from above metallic green with a “scaly” pattern: feathers have dark edging. The lower part of the body is crimson red with an expressed metallic sheen. In males, on the wings, the outermost flight feathers are blue. The area around the eyes in birds of both sexes is featherless and covered with white skin. The male grows long feathers on the “eyebrows” (as long as the body of the bird itself), the vain is developed on them on one side. The “eyebrows” resemble the antennae of some insects. They are coal-black with white tips and stand out against the general background of plumage. By the position of the “eyebrows” the male expresses his mood – he raises them when he is alarmed or annoyed. Females have no “eyebrows”.
The beak of beetle bird is wide and short, and the mouth cut is very large: it reaches the posterior edge of the eye. The bird feeds on berries (swallowing them whole), soft insects and other invertebrates (worms, snails).
Beetle bird is found in the mountains, preferring places overgrown with bushes. It nests on rocks, often making its nest at the base of the nest of akatu, a giant bird of prey. This species is polygamous: up to five females can nest on the territory of one male at once. The male performs courtship rtual alone, choosing for this purpose a long dry branch or the root of a tree growing on rocks. It spins and bounces on a branch in the rays of the sun, making its plumage sparkle like a gem. The mating song consists of a series of shrill monotonous calls, similar to the cricket chirp, but more sonorous.
Unlike many other cotingid birds, beetle bird is a fairly skillful builder: its nest is strong enough, woven from grass and representing a spherical construction. In the clutch there are 2-3 white eggs incubated only by the female. The male protects the territory from rivals, engaging with them in hard fights, accompanied by threatening trills and displaying of bright plumage. Females get food for nestlings on their own; the male takes part in caring for the offspring very irregularly – for him feeding the offspring of all the females of the harem is a way to show his power over them. Nestlings hatch blind, but covered with short black down. They begin to see clearly at about five days of age, and two weeks after hatching from eggs, they fully fledge. Young birds leave the nest at the age of about 20 days. Their first plumage is completely different from the brilliant outfit of adult birds: juveniles are chestnut-brown with a dark back. The area around the eyes of fledglings is covered with small feathers.
The female supplements them for another three to four days, and then starts a new nesting cycle. Birds of this species have up to three broods per year.

Donkey armadillo, or tatu-burro (Dromarmadillo asellinus)
Order: Edentates (Edentata )
Family: Armadillos (Dasypodidae)
Habitat: South America, plains and foothills in areas with a tropical climate.

Picture by Carlos Pizcueta (Electreel)

Edentata order is one of the few groups of South American mammals that were able to survive after representatives of the fauna of North America came across the Isthmus of Panama to previously isolated South America in the Pliocene and Pleistocene. Most of the groups of animals that formed in isolation in South America became extinct shortly after this event. However, these peculiar animals managed not only to survive, but also even to settle in the opposite direction: to colonize North America (giant sloths and armadillos did it), but there man most likely exterminated them. In the historical era, the nine-banded armadillo also penetrated far to the north, but the ice age that ended the human era threw this thermophilic species further south.
In South America, the evolution of the edentates continued more successfully, although the disappearance of the rainforest led to the extinction of all sloths. However, armadillos achieved significant evolutionary success in the Neocene. Among them, burrowing and specialized insectivorous species appeared, and one of the species of these animals developed into a completely peculiar creature.
At the first glance at this animal, it may not be clear who is it and which relative is it. With its constitution, this animal is more like a cartoon donkey in barding like Medieval horse one. However, this beast has a significant difference from horses and donkeys, known to man – it is not an artificially made barding, but its own shell. This creature is a kind of running armadillos, donkey armadillo, or tatu-burro. The tatu-burro has partly lost the habits characteristic of armadillos: it does not dig holes, and leads an exclusively terrestrial lifestyle. The shell of this animal has become very durable: it protects the animal from the attack of predators. The shell of a donkey armadillo consists of several movably articulated parts. One solid shield, covered with many horny tubercles, protects the shoulders and scruff of the animal. There is a second similar shield on the croup of the animal. Between them on the body there are several narrow bands, which only partially make the body mobile. The animal has a thin tail covered with small corneous shields.
Neck of donkey armadillo is protected by plates on the sides and on top, and a thick frontal shield grows on the head. The corneous plates on this shield have developed into large cone-like outgrowths. If necessary, the animal can use it as a battering ram. The ears of the animal protrude on the sides of its frontal shield. They are mobile, elongated, a bit donkey-like – this feature determined the name of the beast. Since tatu-burro lives in a warm climate, but most of its body is covered with a shell, it faces the problem of heat emission. Its ears cope with this role – in them a network of blood vessels is developed. In hot weather, the ears of the animal turn pink – blood vessels dilate, and the blood emits the excess of the heat through their thin skin.
The lower part of the animal’s body is not protected by shell; long, thin wool grows on it. On the neck and lower part of the head, the hair is shorter and thicker, which makes it look like a “beard”. Jaws of the animal are relatively short, the tip of the muzzle is mobile and flexible. The color of the animal is two-tone: shell plates are reddish-brown, and the coat is light gray.
Tatu-burro is a relatively large animal that looks like a long-legged pig. Its height at the shoulders is about a meter, and its body length (without tail) is about one and a half meters. This animal inherited from its ancestors, ordinary-looking armadillos, the ability to run quickly. In this regard, its legs have changed significantly. Hind legs of tatu-burro are slightly longer than front ones, they have become partially, and the front ones are completely digitigrade. Claws on the hind legs have turned into a kind of hooves, and the animal rests on them and on the pads of the third and fourth toes. The II and V toes do not reach the ground, only short claws grow on them. On the forelegs, II, III and IV fingers are well-developed, armed with long claws with a sharp lateral edge. With the help of these claws, the animal can not only run, but also get food: dig holes and termite mounds, and also to destroy the well-fortified clay nests of ground-dwelling birds – prairie pipe birds. If the shell does not save the animal from enemies, tatu-burro can defend itself actively – animal sits on its hind legs and inflicts deep wounds on the attacking predator with the claws of its front legs.
This peculiar edentate leads an interesting way of life – it is an omnivorous species, in the diet of which food of animal origin takes a significant place. This animal has a high immunity to poisons; therefore it even feeds on animals that are passed by by other predators. It can trample and eat poisonous snakes and frogs, gathers poisonous beetles and eats them without harm to health. Tatu-burro willingly feeds on carrion, searching for it with the help of its keen sense of smell. This beast may be seen among those who wait patiently for the predator to feed itself and leave its prey. But tatu-burro is not able to get meat on its own: it has a very low intellect, and this animal does not know how to hunt at all. It only eats those animals that cannot escape from it, or is content with the remains of the prey of large predators. In addition, due to its weak teeth, tatu-burro cannot crack bones like hyenas or other specialized scavengers, and feeds only on soft parts of carcass. But strong stomach allows it to eat even meat, that has begun to decompose, which other predators do not eat.
There is no well-defined breeding season for tatu-burro. This species does not form permanent families, animals of different sexes meet each other only during mating. Pregnancy lasts about 4 months. The female gives birth to only two large and well-developed cubs. For tatu-burro, a common feature of armadillos is characteristic – cubs of the same brood are identical twins. They become independent early – a month-old cub already leaves its mother and gets food on its own. The female gives birth to about three broods in two years.
While adolescents of this species are small, they do not risk approaching the prey of large predators and are content with small animals, mainly invertebrates. They also eat plant foods – berries and flowers of herbaceous plants. Then, from about two years of age, having reached the size characteristic of an adult animal, they switch to feeding on carrion. The life span of a donkey armadillo is about 15 years.

Forest tapirotherium (Tapirotherium probosciferus)
Order: Odd-toed ungulates (Perissodactyla)
Family: Tapirs (Tapiridae)
Habitat: South America, woods.

Picture by Tim Morris

In the process of evolution, nature set up a kind of “experiments” in various parts of the Earth, when at different times, on different continents, but in similar natural conditions, living creatures of very similar anatomical features appeared, descending nevertheless from completely different ancestors. So, in the Cenozoic of South America, representatives of local ungulates, pyrotheres (Pyrotheria), appeared – they were beasts, outwardly similar to proboscideans of the Old World and North America. In Neocene, the situation was partly repeated: in due course of evolution, pigs in Eurasia acquired a proboscis, which allows them to gather food and to produce various sounds. In South America, the evolution of tapirs, relict odd-toed ungulates, continued. They also developed a trunk that serves a variety of purposes. The proboscis descendants of tapirs represent a separate genus of these animals – Tapiroterium.
The largest representative of the genus is the forest tapirotherium. It is a very large animal with a distinctive appearance. The animal is a bit like a mastodon: the body length of the forest tapirotherium reaches 4 meters with a height at the shoulders of over 2 meters and a weight of up to 3 tons. The back of the animal is slightly curved upward, the head is massive. The legs of tapirotherium are thick, with wide feet, each of which ends with three hooves. Under the fingers and toes of the animal, there are pads of elastic cartilaginous tissue, saturated with fat, and due to it, the steps of tapirotherium are silent. The relatively large support area does not make tapirotherium a good runner, but it allows it to wander on swampy soils and swim beautifully. Tapirotheres live along the river banks in northern and central South America, sharing habitats with a local giant rodent, barocavia (Barocavia). However, the competition between them is softened because tapirotheres are active during the day and prefer to feed on land. And barocavias feed on the shore at night. In addition, tapirotherium is able to feed on branches from trees inaccessible to a giant rodent, and can even stand on its hind legs for a short time. Tapirotheres are also found in the rainforest that grows in the Amazon and Hippolyte river basins. In the dense forest, their place of residence can be easily identified by the wide paths laid in the forest.
The forest tapirotherium lives in warm climates, so it has very sparse and short hair. The animal is dark brown with a lighter head and a cross-striped trunk.
The most notable feature of tapirotherium is its long trunk evolved from the short proboscis of ancestral tapir. The length of the trunk of tapirotherium exceeds the length of its skull. The skull of the animal is short and deep, the nasal openings are shifted back and up, like the nostrils on the skull of an elephant. The tapirotherium’s trunk is mobile, and animals can pick off thin stems of grass or young leaves of a bush with it. Then, with the help of the trunk, these animals communicate: the color of the trunk is distinguishable from afar, and the animals give each other signals by waving the trunk, raising or lowering it. In addition, with the help of the trunk, tapirotheres can produce a variety of sounds: trump, purr and squeak. Unlike Holocene elephants and Neocene elephant-like pigs of Eurasia, tapirotheres lack tusks.
Also, tapirotheres are distinguished from elephants by short ears. Nevertheless, for a large animal in a hot climate, the problem of heat emission is much more acute. For this purpose, these animals developed a large fold of skin on the lower part of the neck and chest. In hot weather, the blood vessels that penetrate the skin dilate, emitting some of the heat.
Tapirotheres live alone or in small herds of 5-10 animals. Usually old males keep solitarily in the territory of a herd of females with cubs. Young and mature males form leks of “bachelors” outside the breeding season.
Pregnancy lasts about 15 months. The female gives birth to only one cub; at the birth of twins, one cub, as a rule, does not survive. The cub stays with its mother for a long time: it feeds on milk for up to a year, gradually getting accustomed to the food of adult animals. After switching to plant food, young females remain in the herd for life, and males stay there until about two years of age. After that, they leave the parental herd and enter the lek of “bachelor” males. They become sexually mature at the age of 5 years (females do it a year earlier). The life span of tapirotherium can be up to 60 years.

One more species lives in mountain regions of South America: mountain tapirotherium (Tapirotherium montanicolus). It is smaller species (like usual tapir by size), adapted to inhabiting in cool mountain climate. At it there are rather short legs and lengthened trunk: so it is easier to move in cross-country terrain. Also it does not have plica of skin on neck, characteristic for its large relative, and it is covered with rich wool. This species is colored brighter than forest tapirotherium: at it light longitudinal strips on dark brown woolare kept. It is the display of juvenile colouring. Strips are especially distinct on shoulders and basis of neck, and around of eyes there are big sites of light wool on black background. This animal lives in Andes where prefers to live in mountain valleys. Mountain tapirotherium differs from forest congener in dense constitution, narrower feet and stronger hoofs. Despite of significant weight, this animal is able to climb on rather abrupt slopes though it makes it seldom – usually animals of this species live settled in mountain valleys, and migrate only at lack of forage or because of inclement weather conditions. This animal is very numerous near to Totora Lake on Altiplano Plateau in Andes.
Obviously, the close relative of mountain tapirotherium is Chilean tapirotherium (Tapirotherium chiliensis) – medium-sized animal and rather easy constitution. Chilean tapirotheriums inhabit narrow strip of land between Andes and Pacific coast of South America. These animals live in various habitats: from foothills up to ocean coast. They have long legs and trunk, reach the weight about one ton and can run quickly. At Chilean tapirotherium there are rather small feet and hoofs, and also neck is lengthened. It has grey colouring with longitudinal black strips on groats and back. This species keeps in harems of male (sometimes two males – main and subordinated) and several females with cubs of various ages. Populations living near the ocean frequently come to the coast where animals drink salt water and eat seaweed cast ashore.

Barocavia (Barocavia potamophyla)
Order: Rodents (Rodentia)
Family: Capybaras (Hydrochoeridae)
Habitat: rivers and bushes of South America.

During the most part of Cenozoic South America was isolated continent. Its flora and fauna developed independently from other continents and has reached high level of endemism and originality. In late Cenozoic connection of South and North America was restored and as a result of immigration of North-American species the most part of South-American ones appeared in conditions of isolation and not taking place similar “durability tests” has died out. But some groups have remained rather widely spread and various – for example, characteristic South-American rodents. When in Neocene South America appeared isolated from world again around by Panama passage, these animals became basic forms of local herbivores having evolved numerous and various species having ecological analogues in other parts of the world: original “doubles” of antelopes and pigs. And the place of hippopotamus in rivers and lakes of South America was occupied by giant rodent – huge barocavia, the descendant of capybara.
Barocavias are widely settled in rivers of South America. In constant reservoirs they live settled life, and in seasonal drought areas had turned to nomades and make migrations to deeper rivers and lakes. Usually these huge animals spend almost all day in the river eating or having a rest, and in the evening come to bank meadows to graze.
The barocavia is huge semi-aquatic rodent resembling hippopotamus externally and by habit of life. It grows to 3 – 4 meter length (male is larger) at height at a shoulder up to one and half - two meters. The adult male of this species can weigh up to three tons. At barocavia there is thick skin covered with thin rough wool of brownish color. Tail at this giant rodent is not present.
Head of barocavia is disproportionally big, having big cheek-bones, and heavy. On the top jaw of animal long rigid whiskers grow. Incisors in bottom jaw are wide and shovel-like. They are directed forward and serve for raking of floating plants from water surface and for excavation of roots from bottom or coast. Top incisors are covered with white enamel, their length reaches 20 cm. They permit to have a cut through even trunk of young tree easily, and in case of predator attack help to give them adequate repulse. Molars of barocavia are wide and knobby. It is connected with diet of animal: barocavia consumes for day plenty of enough soft and sappy vegetative food and chews the most part of day.
Small eyes and short rounded ears of barocavia are shifted to the top part of head as at hippopotamus. At this animal there is bad sight but keen sense of smell and excellent hearing.
Legs of barocavia are plantigrade, thick and short. Toes are united by common cover of soft tissues and form the structure similar by form to the elephant foot. Under them the pillow of elastic tissue impregnated with fat allowing an animal to walk easily, springly and silently despite of apparent awkwardness is located. Claws (on forward leg their number is four, on back one - three) are thick and hoof-like. Barocavia can swim and dive well rowing by legs. Under water animal walks easily and even is to some extent graceful, slightly touching a bottom. In case of necessity these animals easily can cross rivers some kilometers wide.
Barocavias live in big herds numbering up to 30 – 40 individuals. Such large herd is non-uniform: in it there are some breeding groups – one adult male for 3 – 5 females and their cubs of first year of life. Herds of smaller size are, as a rule, groups of bachelor males not having families by different reasons. All breeding groups in herd are approximately equal by rank. In case of danger herd can unite and defend from predator collectively. Barocavias try to drive off ground predators widely opening mouth and showing huge teeth and light pink gums. Thus adult animals abruptly bellow and growl. Water predators - large carnivorous fishes – as a rule, are not dangerous to barocavias, though they can drown and eat newborn cubs. At the case of fish attack adults protect cubs by bodies, rear and fall to water, splashing fountains of water and trying to trample attacking fish. Sometimes adult animals try to bite fish or to snap it and to cast ashore (according observations of zoologists African hippopotamuses of Holocene epoch acted this way).
In rainseason when rivers are widely overflowed and transform significant areas to marshy plains, barocavias leave main channel of river and go to near lakes and bogs. Here they feed with marsh plants plentifully expanding on damp ground, supplementing the diet by branches of trees and bushes. Each herd occupies the certain territory which edges are marked by heaps of manure. By smell of manure any neighbour can know as great the herd is, what animals make of it, and as frequently it visits this place.
These rodents spend hottest time of day in water having a rest and eating water vegetation. During feeding barocavia sticks teeth under reed turf, pulls out the whole sheaf of stalks by strong movement of head upwards, “rinses” it in water by lateral movements of head and then starts to chew phlegmatically. These rodents to sleep prefer on land in places where ground predators can not reach: frequently “bedrooms” of barocavias are situated on small islands among bog or on sandy islands in channel of river. Dream time at the barocavia lasts from second half of night till late morning.
The role of barocavia in ecosystems of South American rivers is great: eating plants they interfere river overgrowing and bogging, and on their manure phytoplankton – basis of efficiency of river ecosystems – plentifully reproduces. Eating bushes on river banks barocavias promote development of graminoid communities serving for feed to local running rodents deermaras and giant pacas.
The breeding season at barocavias begins approximately in middle of rainseason: thus cubs will be born in the most favorable season, and the probability of their survival will be much higher. Out of breeding season males practically do not notice each other and even can graze grass side by side. But when the female from breeding group shows the readiness for pairing, the male becomes terrible and jealous husband. Bassy uterinely roaring it snatches to any one in which competitor will be seen. During intraspecific duels barocavias do not use huge teeth and simply push each other by shoulders and strike impacts by forehead or lateral part of head.
Caring for the female male slightly pushes her head, puts his head to her back or neck. Thus he “coos” – utters special abrupt humming sounds, and walks “on tiptoe” highly lifted head up and trying to seem even larger. If the female is not ready to pairing, she keeps head to the caring male and from time to time quietly growls showing incisors. Accepting male carings female nestles against his side, “coos” in unison, and sniffs head of male from below. Pairing at massive barocavias occurs in water.
Pregnancy lasts about eight months, and once a year female gives rise to two well-advanced cubs with opened eyes, covered with wool. The newborn barocavia weighs about 50 kgs. Already at the first day of life the cub can walk and even tries to swim. At fortnight age young barocavia tries to eat grass and completely passes to feeding by plants at the age of three months. At this time young animal can weigh already up to 300 kgs. Barocavia becomes completely adult at the age of about two years, and life expectancy can be about 30 - 40 years.

Tyrannocharax (Tyrannocharax deinodontus)
Order: Characids (Characiformes)
Family: Trahiras (Etythrinidae)
Habitat: shallow fresh reservoirs in tropical zone of South America.
After climatic catastrophes of the late Holocene and early Neocene, many of the previously flourishing groups of animals became extinct. Such a fate befell almost all crocodiles that have existed on Earth since the Triassic period of the Mesozoic era. Only a few representatives of this order live on Earth in the Neocene epoch, and in many places where they lived before, completely different animals replaced them in the ecological niche of a large aquatic predator. Most often these are various turtles and lizards, but in South America, where an extensive network of rivers and lakes has been preserved, fish have taken on the role of a formidable aquatic predator. In the Holocene epoch, in the basins of tropical South American rivers, trahiras were widespread – large and quarrelsome predatory fish, sometimes reaching a meter in length. They lay in wait for prey, hiding among the plants to make an ambush. The same tactic is used with great success by their descendant – the giant tyrannocharax.
The length of the almost cylindrical body of tyrannocharax reaches four and a half meters – it is one of the largest bony fish of the Neocene Earth. About a meter of this length falls on a huge head with an elongated snout and pointed teeth, looking like nails curved back. The weight of this monstrous fish may reach 300-350 kilograms. Head is covered with a dense shell of ossificated skin, which gives it additional strength and protects it from accidental damage that large prey can inflict on this predator. In the upper part of the head there are small black eyes, and approximately in the middle between the eyes and the tip of the muzzle there are sensitive nostrils.
The constitution gives out in this fish a typical ambush predator, not swimming long and fast. Tyrannocharax spends almost all the time, hiding among the abundant aquatic vegetation at a depth of about 1-1.5 m. The pattern on its scales helps even such a huge fish to remain unnoticed. On the sides of tyrannocharax there is an uneven reticular pattern: black spots on the greenish-gray background, merging into vertical stripes. The back of this fish is brown-black with a few light spots.
The caudal fin of tyrannocharax is short and rounded, and the caudal peduncle is deep and muscular. Such proportions are typical for fish capable of making a sharp rush. The dorsal fin extends from about the middle of the back almost to the beginning of the caudal peduncle; the adipose fin is absent. The pectoral and pelvic fins of the fish are well developed and shifted downward.
Living in shallow, highly heated water bodies, large fishes face with one problem: the body requires a lot of oxygen, and its content in the water is low. Tyrannocharax solves this problem with an adaptation that it inherited from its ancestors. The swim bladder of this fish is opened – it has turned into a kind of lung. From time to time, the huge fish carefully emerges to the surface of the water and breathes. After that, the tyrannocharax can lie in ambush for up to half an hour, not giving itself away to possible prey. The lung helps the fish to survive in drought conditions: when reservoirs dry up, tyrannocharax can move from one reservoir to another, bending with the whole body and helping itself with pectoral and pelvic fins. At the same time, the fish keeps the gill covers closed, protecting the gills from drying out, and breaths exclusively with the help of the lung.
The female is paler and fuller than the male, and, in addition, is about half a meter longer and heavier by 20-30 kilograms. With such an alignment of forces, given the very quarrelsome and aggressive nature of the fish themselves, the male is required to be very careful when communicating with the female during the spawning period. The courtship ritual of tyrannocharaxes is quite long; the male gradually accustoms the female to his presence, keeping on the edge of her territory. At any moment he is ready to retreat to a respectful distance, as soon as the female shows signs of displeasure from his presence. However, over time, the female gets used to the male, and he can carefully approach her. During the courtship display, the male becomes brighter: his body acquires a rich green color with velvet-black stripes, and the lower part of the head becomes bright red. Caring for the female, male swims next to her, stretching his fins and emitting series of clicks audible from under water, especially at night.
Tyrannocharax belongs to phytophiles: this fish spawns on the leaves of small-leaved plants. Before spawning, a pair of fish chooses thickets of an aquatic plant with small leaves and tears up all vegetation at a distance of two meters from it. After that, the mating ritual begins, during which the male drives the female into the thickets and presses against her side. After several trial attempts, the pair spawns eggs – about 20 thousand rather large eggs.
The female almost immediately leaves the spawning ground, and the male stays to guard the offspring. At this time, it becomes almost entirely black, only a few green spots are noticeable on the sides. His aggressiveness at this time increases so much that even a female larger than him is forced to retreat away from the clutch.
The incubation of eggs lasts about a week, after which the male leaves the clutch to fend for itself. The first days the larvae hide among the plants, at the age of three days they begin to swim and feed on small crustaceans. They grow rapidly, and at a length of about 1 centimeter they can already attack the fry of other fish. Cannibalism is characteristic of this species at any stage of development, so only a few fishes survive to adulthood. Sexual maturity in young fish occurs at the age of about seven years; life expectancy reaches 50 years or more.
Tyrannocharax hunts large mammals, waterfowl and large fish. The strength of the jaws of this predator is such that it can easily pierce with its teeth even the shell of a small turtle. Usually the fish lurks near the favorite watering places of large animals, and waits until any animal enters the water too far. Then a sharp throw follows, and the prey disappears under the water. Tyrannocharax has a grip of steel on its jaws. Even if the animal can escape, it will most likely die from blood loss: pointed teeth of tyrannocharax inflict deep wounds. This fish catches waterfowl, grabbing them from under the water. Tyrannocharax also does not disdain small prey: chicks of small birds, that have fallen into the water, and small mammals, fleeing from a flood, can easily end their lives in its teeth. A sated fish hides in depth and lays in deep for some days, while digesting its prey.

Goliath bird louse (Megalaemobothrion goliath)
Order: Chewing lice (Mallophaga)
Family: Laemobothriids (Laemobothriidae)
Habitat: South America, a parasite of large birds.
The evolution of each species of animals and plants is closely related to the fate of the species that surround it – taken together, the species of animals and plants form ecosystems and determine the characteristics of each other’s habitat. Particularly close are the relations between species, which are a parasite and a host for each other. The host itself represents a habitat of the parasite, therefore, any changes in the structure, physiology or lifestyle of the host immediately affect its parasites, forcing them to die out or evolve in one direction or another. The dependence of the parasite on the host leads to the fact that its specialization is very strict – the range of possible hosts is greatly narrowed, and sometimes the parasite is able to live on only one species of the host organism. Parasites are present among various groups of animals, and are not uncommon among insects. Some orders of insects are represented exclusively by parasitic forms. Chewing lice are highly specialized bird parasites (some genera of chewing lice of Trichodectidae family live not on birds, but on mammals, but their specialization is as strict as that of “typical” chewing lice). They eat the corneous derivatives of bird skin – feathers and scales of the epidermis. Usually these insects are small in size and have a flattened body. In the Holocene, most of the chewing lice were very small in size, measured in millimeters, with one eagle parasite about one centimeter long being a giant among them.
However, this small “giant” of Holocene epoch would be undersized in comparison with the largest species of chewing lice of the Neocene epoch, which lives in the feathers of some South American birds. This insect reaches a length of about 3 cm, and for its gigantic size it is called the goliath bird louse.
It is an insect with thin translucent body integuments, with a narrow thorax and short tenacious legs. The mandibulae of this insect are cutting and directed forward. The head is flat, wedge-shaped, narrowed in front. Antennae are short, non-mobile and directed backwards. There are no eyes – chewing lice constantly live among the feathers of birds, so vision does not play any role in their life.
The abdomen of the goliath louse is long, flexible and worm-like. There are thick hook-shaped setae along the edges of each body segment – two of them protrude upward and two downward. They help the large insect to anchor between the feathers of the host bird. Typically, this chewing louse stays between two overlapping feathers, anchored by its hooked bristles. On the sides of each abdominal segment, there is a tuft of strong setae directed backward.
The goliath puff louse lives in the feathers of large local carnivorous birds: akatu (Sciopterornis acatou) and hunting heron (Graviardea venatrissa). Usually chewing lice are strictly specific for a certain species of birds, but this species can successfully survive and develop on both species, since these birds are not too far from each other in terms of systematics. Obviously, this species originated from some species of the genus Laemobothrion, the species of which were found on birds of various taxonomic groups: falcon birds, cathartids, rails and gallinules. In the process of evolution, when some species of South American birds began to increase in size, the ancestors of this insect also began to grow.
Chewing lice prefer strictly defined areas of plumage of birds, and several species of these parasites can live on the same bird without competing with each other. The goliath bird louse prefers to settle under the wings and in the back of the bird’s body, where it is relatively rarely disturbed. If necessary, this insect can move very quickly between the feathers of the host bird, writhing like a worm and clinging to the feathers with bristles growing on the sides of the abdominal segments.
Goliath bird louse lives in constant conditions formed on the surface of the bird’s body, so it reproduces all year round without interruption. The female lays about fifty small eggs daily, gluing them in rows to growing feathers.
All chewing lice are hemimetabolous insects. The larvae of this species differ from the adult goliath bird lice not only in size, but also in proportions. They are very small (about 1.5 mm long), with a slender body, a wide head with two notches on the sides, and relatively long legs. During its development, the larva of goliath bird louse passes 12-13 molts. The larvae of this species are very mobile. Due to its size, it is difficult for an adult insect to move from one bird to another – usually birds become infected with these parasites during mating, and chicks get them from their parents. However, insects of this species, settling in colonies of a hunting heron, can easily move from one bird to another in the course of the daily life of these birds. On the hunting heron, the goliath bird louse differs in smaller size, and reaches maturity, passing one molt less. On the contrary, goliath chewing lice that settled on the body of the akatu grow faster and turn out to be more fertile than their relatives from the hunting heron. The larvae can actively spread from bird to bird, attaching with their legs and thickened mobile antennae to the legs of blood-sucking insects – horseflies and other flies. When the insect lands to suck blood, goliath louse larvae rush to it and cling to its legs. At this moment, the recesses on the sides of the head provide tangible benefits to the larva of the chewing lice: the movable thick antenna folds back and clamps the leg of the flying insect in the recess, like a trap. The larva of the bird louse hangs on a fly or horsefly, and flies to the body of another host. So it can settle down to about the third molt. Later, when the larva reaches a length of 2-3 mm, it loses its ability to such air passages. In addition, it becomes too large for such a “trip”, and the fly can simply throw it off. The full development cycle lasts about 3 weeks.

Feather beetle (Plumovermis protector)
Order: Coleoptera, or Beetles (Coleoptera)
Family: Rove beetles (Staphylinidae)
Habitat: South America, bird feathers.

Picture by Biolog

Beetles are one of the largest orders of both insects and animals in general. Their order is represented by hundreds of thousands of species that have a different lifestyle and eat variety kinds of food. Among the beetles, there are herbivorous and carnivorous species, and there is even a small number of parasites. Their strict specialization often allows them to avoid intense competition, and in the Neocene fauna, a considerable number of beetles is represented with such specialized species.
In the plumage of large birds living in South America, one species of beetles is often found. At first glance, it is difficult to classify it as a beetle, but it is revealed by the characteristic structure of the wings: their first pair is turned into rigid elytra. They are very short, and do not completely cover the abdomen – this feature is typical for carnivorous rove beetles, to which this insect belongs. For the characteristic way of life, this representative of rove beetles is named as feather beetle.
It is a typical representative of the family, a predatory beetle that can fly. It flies from one bird to another in search of food – various parasitic insects that breed in their plumage. For hunting, this beetle uses a very keen sense of smell: it easily recognizes the smell of parasitic insects against the background of the smell of the bird on which they live. In this it is helped by long feathery antennae with a small “club” at the tip. Sensitive cells are located on the lateral outgrowths of the antennae.
The elytra of this insect are very short – they do not cover even a third of the abdomen. The body of the feather beetle is flexible and long (its specific name literally means “feather worm”). When the beetle crawls along the feathers of birds, it folds its antennae under the edges of the head from below, so as not to damage them.
The head of the feather beetle helps it to move among the plumage of the bird: it is flat, narrow and wedge-shaped. Since the insect flies well and spends part of its time outside the birds, it has large eyes, elongated along the lateral edges of the head. Mandibulae of this beetle are very large – longer than half of the head. On their inner edges there are sharp teeth, with the help of which the insect grabs prey. Also, the caught feather beetle tries to bite the predator that grabbed it.
Mandibulae represent not the feather beetle’s only defense. It is poisonous: cantharidin is accumulated in the hemolymph of the insect. To warn the predator about its inedibility, the insect has a memorable black and red color. The elytra of this beetle are brownish red, smooth and shiny. On the abdomen of the insect there are transverse “velvet” stripes formed of dense red pubescence. Feather beetle’s legs are red. When disturbed, this insect opens the elytra to the sides and exposes a bright red spot on the thoracic segments. Also, the feather beetle lifts its abdomen up, showing its shiny white underside. To protect against mammals and reptiles that use the sense of smell when hunting, there are several pairs of glands on the abdomen of the feather beetle, that secrete an unpleasant-smelling liquid.
All rove beetles are hygrophilous, and the feather beetle is no exception. This insect keeps near water bodies, where it waits for suitable “clients”. Where the reservoir does not dry up and the air is sufficiently humid, the feather beetle spends a short time on birds. However, far from permanent reservoirs, the feather beetle prefers to find a bird of suitable size in the dry season, and waits for an unfavorable season on its body. A relatively favorable microclimate develops under the feathers of the bird, which helps the beetle to survive. If, by the beginning of the dry season, this beetle has not found a bird suitable for life, it switches to an underground lifestyle. With the help of sensitive antennae, it searches for rather humid places – holes of various burrowing animals – and settles there. If necessary, the beetle can dig its own burrows in soft ground.
The female feather beetle lays eggs in dense clumps of grass, and guards them for several days until the larvae hatch. Clutches are repeated every week throughout most of the rainy season. At the same time, the female lays up to 20 relatively large eggs. Nevertheless, the low fecundity of the insect is compensated by the high survival rate of clutches and young larvae.
The larval stage in the feather beetle lasts about a year. The larva is similar to primitive wingless insects: it has an elongated body and well-developed legs, which greatly differs it from the worm-like inactive larvae of most beetles. It can crawl quickly and digs the soil well with a solid head. The body covers of the feather beetle larva are dense and hard, thanks to which it is protected from other soil predators.
During the first weeks of life, the larva lives in clumps of grass and eats small insects that live with it. During the dry season, the larvae, which by this time have passed several molts, and have reached about half of their maximum length, move to underground life. The hard shields of their bodies are connected by an elastic membrane, through which moisture can evaporate, so dry air is deadly for them. Under the ground, the feather beetle larvae live in the holes of rodents and dig their own passages, pursuing burrowing larvae of other beetles and cicadas, as well as worms. In the holes of rodents, the larvae can hunt various parasitic insects, but they are not specialized to the relationship of symbiosis with burrowing mammals, and live without them successfully. The larva, ready for pupation, crawls out almost to the surface of the soil, and hides in clumps of grass, where it pupates under a thin layer of soil. The young beetle digs an exit to the surface with its head.
The flight of feather beetles begins at the very beginning of the rainy season. Insects search for each other, mate on the ground among the grass, and fly in search of birds infected by parasitic insects. Very rarely, these beetles are found on bodies of large mammals, where they also eat parasitic insects.