THE ORIENTAL REALM

The Oriental realm is the smallest of the zoogeographic realms, and, in many respects, it is the most difficult to define. Geographically it is part of the great northern continent and is that section of it that lies to the south of the huge barrier of mountain chains that crease up its south-eastern corner. However it also encompasses the cluster of jungle peninsulas and volcanic island archipelagoes that reach out across the ocean towards the Australasian realm in the south east. The most extensive flat area of the realm is a triangular peninsula 2,000 kilometres (1,250 m) wide by 2,500 kilometres (1,550 m) long, consisting of an old fragment of Gondwana. Most of the rest of the realm is quite new and is formed of fold mountains. The northern boundary is well defined by the ramparts of the mountains. To the west, the boundary lies in a desert region that is continuous with that in the north of the Ethiopian realm. The south-eastern boundary is not well defined. It lies somewhere in the sounds and straits between the strings of islands. Many animals can move from one island to another by swimming across the intervening sea areas, or by drifting on mats of vegetation, or even by walking across when the sea level permits. Some Australasian animals have penetrated well into the Oriental realm in this way, and many Oriental animals have similarly spread into Australasian territory. It is difficult to place a realistic boundary between the two realms here.
The fragment of Gondwana that formed the main peninsula did not break away from its southern supercontinent until the late Jurassic. Since then it has moved northwards across the ancient Tethys sea, out of the southern hemisphere and into the northern, and eventually collided with the northern continent as recently as 30 million years ago. The rapid approach of one continent to the other crumpled up the seafloor sediments between them, and the final collision crushed these up into the greatest mountain range on the face of the Earth today. The disturbance caused by this collision was widespread. Its ripples produced the mountain ranges to the east, those that reach out their crests into the sea to form the peninsulas. The oceanic plate that carried the piece of Gondwana northwards is still forcing its way beneath its neighbour, and producing the chains of volcanic islands that lie between the northern continent and that of Australasia. In geological terms this area is constantly changing.
The Oriental realm is one of mountains and islands, and its habitats reflect this. It is something of a zoological crossroads, many of its animals having arrived from neighbouring realms. Deciduous forest and wooded grasslands lie on the great triangular peninsula. These are grazed and browsed by the descendants of the old Gondwana fauna — big long-necked plant-eaters that are only found on the other fragments of the Gondwana super-continent. These share the plains with creatures more typical of the Palaearctic and Ethiopian realms that have moved in and adapted well to the environment.
The rivers that pour off the mountain ranges produce lush, forested deltas where they flow into the broad bays of the ocean. The deeply indented coastline means that there are few permanent ocean currents and the river sediments can build up into huge deltas here. Trees, such as mangroves, that can withstand flooding by both fresh and salt water, establish themselves on mudbanks and trap more silt by their root systems, so building up more areas of land along the coasts. The forests receive heavy rainfall during the summer months because of the monsoon climate. The warming continent to the north produces rising air masses that draw in moist winds from the sea. In the winter the opposite is the case and dry winds blow outwards from the arid interior. The forests and deltas are home to thousands of different tree-living and aquatic dinosaurs, many of them evolved from creatures that originated in the Ethiopian, Palaearctic and Australasian realms.
The mountains to the north are the highest on Earth. They are also some of the steepest. High mountain peaks and glaciated ridges can drop to tropical forested ravines and valleys within a few kilometres, passing through narrow zones of alpine plants, and rhododendron and bamboo forests on the way. The alpine plants found at high altitudes are browsed by nimble-footed dinosaurs, only a few kilometres from where tropical forest dinosaurs browse the steamy forests in the deep valleys.
Deserts lie in the west, defining the boundary to the realm. Across these have travelled a number of dinosaurs adapted to arid conditions, which have then gone on to develop quite easily into forest-dwellers.

Savanna – plains

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RAJAPHANT

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Gregisaurus titanops

During the Tertiary a large triangular piece of ancient Gondwana, over 3,000 kilometres (1,900 m) long and 2,500 kilometres (1,550 m) broad, moved north-eastwards across the Tethys ocean and fused with the northern continent. It threw up the greatest mountain range on Earth along the join. The Gondwana animal life continued on this new triangular peninsula with little change, isolated from the northern continent by the mountain range.
The largest animal now on the sub-continent is the rajaphant, evolved from the Cretaceous titanosaurs. It wanders in small herds, grazing the yellow grasses of the central plains. Although its physical appearance has not changed very much from that of its ancestors, it has developed a complex social structure for life in the exposed grasslands. It has also evolved a feeding mechanism that allows it to eat tough grasses as well as the soft leaves of the bushes and trees. The mouth is broad and the teeth are sharp enough to crop grass, but not strong enough to chew it. The grass is swallowed in vast quantities and collects in an enormous muscular gizzard, a metre (3 ft) wide, in the forward part of the stomach. There it is pounded and crushed to a digestible pulp by masses of hard stones that are deliberately swallowed by the rajaphant from time to time.

Each rajaphant herd has a strict social structure, and this is especially evident while the herd is on the march across the grasslands in the rainy season. Out in front is an old bull, the undisputed leader of the herd. The younger bulls march along the flanks in a defensive formation. The females shepherd the calves in a knot in the centre of the herd.

 

The open plains and grasslands are visited by many species of predatory birds and hunting pterosaurs, that soar and circle in the hot skies searching for likely victims. Anything moving on the exposed ground is a potential meal.

 

 

The Last of the Stegosaurs Until recently the sub-continent was home to the last remaining stegosaurs. This group of armoured dinosaurs died out over the rest of the world in mid-Cretaceous times. However, several species survived throughout the Tertiary period, on this isolated continent, undisturbed by more advanced beasts. The climatic changes at the beginning of the Ice Age two million years ago killed them off.

The rajaphant herds have evolved defensive habits and take great care to protect their vulnerable young against the predators. The adults cluster round and lash out at the swooping hunters with their long necks and teeth, and their heavy whip-like tails.

 

The hanuhan lives in small family groups, usually scattered over a wide area of mountainside. The food is so sparse at altitudes of about 4,000 metres (13,500 ft) that larger concentrations of animals would not survive. The agility of the hanuhans enables them to move from one bleak pasture to another with ease, hopping and leaping from rock to rock, balanced by the stiff rod of the tail.

 

 

The five-fingered hand that was so typical of the hypsilophodonts has been retained in the taddey. The small first and fifth fingers have become versatile and opposable, acting as small thumbs that can fold over the palm. The resultant hand is able to firmly grasp the bamboo stems which are taddey’s main food. The beak is used to scrape leaves and shoots from the woody canes.

Barren land – mountains

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TADDEY

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Multipollex moffati

Well below the snowline, beyond the bare rocks and sparse alpine plants that are the habitat of the hanuhan, the mountains fall away, slope after slope, into the lower flanks and the foothills. On the slopes that reach downwards from about 4,000 metres (13,500 ft) to the misty regions of about 2,000 metres (7,000 ft), the climate is equable and the vegetation more prolific. In the higher reaches the alpine meadows give way to rhododendron scrub, and then to belts of bamboo forest. The greater variety and volume of plants means that more animals live here than further up. One of the largest of these is the taddey. Another descendant of the hypsilophodonts, probably from the same stock as gave rise to the hanuhan, the taddey is a slow-moving forest animal that feeds almost entirely on bamboo shoots. Several species and subspecies of taddey exist in the bamboo thickets, each one being isolated from the others on particular ranges of foothills. It is a large and heavy animal, unlike its hypsilophodont ancestors, and is able to maintain its slow way of life in the absence of ground-living predators in the rhododendron and bamboo forests.

Tropical rainforest – mountains

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NUMBSKULL

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Sphaeracephalus riparus

The great mountain range is young, but it is already deeply weathered and eroded. Annually, melting snows from the higher slopes and the constantly decaying glaciers produce torrents of water that form streams cascading from the heights towards the distant plains and ocean. At the same time the mountain range is continually pushed upwards by the inexorable movements of the Earth’s crust. As the mountains rise, the river gorges deepen. This has led to an unusual circumstance, in which a major eastward-flowing river on the northern flanks of the range has turned south and cut right across the mountain system to reach the sea in a mass of deltas to the south. Cutting through the range, it has formed a gorge that is the deepest on Earth. The lush vegetation that grows along the narrow banks of the river in the depths of the gorge supports its own wildlife. The most typical animal is the numbskull, one of the pachycephalosaurs, or bone-headed dinosaurs. It has changed very little since the group evolved in Cretaceous times, and it still pursues the same herbivorous life style. It lives in herds and family groups in the river gorge, with the males periodically sparring with one another for leadership of the herd. The numbskull is bipedal and roams through the tropical forest found in the gorge, maintaining balance with the strong tail.

 

Barren land – mountains

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HANUHAN

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Grimposaurus pernipes

The large size of the taddey – up to 2 metres (6 ft) long without the tail – and its lazy appearance, makes it quite different from its agile hypsilophodont ancestors.

At rest, treewyrms lie along boughs or dangle like creepers. The insides of their hind legs have an arrangement of strong scales angled inwards allowing them to grip branches firmly.

The treewyrm feeds on arboreal insects and small vertebrates. It can hunt these with its stereoscopic vision and can catch them with rapid flips of its long neck and snaps of its jaws.

The wings, or patagia, of the flurrit, although not allowing it to fly as a pterosaur’s wings would, enable the flurrit to glide for great distances between the trees. Its hollow bones help to keep down the body weight. It can control its gliding flight path by altering the position of its arms and by swinging its long tail. When hunting or feeding below, the flurrit folds its patagia away.

The nervous system of the flurrit is highly developed in order to coordinate the movements of its flight and keep it under control.

The flurrit is very small, its body and head being about 30 centimetres (1 ft) long. The underside of the wings has a very bright pattern, invisible when the wings are folded, and this is used for display and intimidation.

Tropical rainforest

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FLURRIT

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Labisaurus alatus

As in all other tropical forest areas the tree-living animals of the Oriental realm have evolved into a vast variety of strange forms. Many of these have developed from the arbrosaurs of the other realms. The tropical forests here support an extensive range of plants, and so there are many different kinds of insects and plant-living creatures found in the forest. They in turn become prey for a wide variety of carnivorous and insectivorous animals.
One insectivorous animal that is found only in the forests of the eastern islands is the gliding arbrosaur, the flurrit. Most arbrosaurs are able to leap great distances from branch to branch and from tree to tree, in order to look for more prey. The flurrit evolved its gliding habit from these beginnings. Flaps of skin, or patagia, between the forelimbs and the body, developed and became aerodynamic structures. These do not allow the animal literally to fly but they enable it to glide from one tree to another. The flurrit’s glide path has an angle of descent of about 45 degrees which can be controlled to some extent by the positions of the arms. When not in use the patagia fold away against the animal’s sides and do not interfere with its hunting. Like the other arbrosaurs, it feeds mainly on insects which it catches by winkling them out of their tree burrows with its long fingers. Different species of flurrit are found on other islands. They are distinguished from one another by their markings.

Tropical rainforest

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TREEWYRM

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Arbroserperus longus

The bulk of the lowland areas of the Oriental realm consists of tropical forest. The climate, known as a monsoon climate, supports forest habitats. During the summer the constant heat over the northern continent gives rise to low pressure areas that bring moist winds in from the ocean that lies to the south. A rainy season ensues. During the winter the continent cools and dry air blows out towards the ocean. The mainland forests thrive in this seasonal rainfall, but the forests of the island chains to the south-east receive the wet winds all year round – both northerly and southerly winds blowing over sea areas before reaching them – and are particularly luxurious. Tree life is abundant, and many species of treewyrm exist in the tropical forest.
The treewyrm is directly descended from the desert burrowing wyrms of the Ethiopian realm (page 36). Although the sinuous shape developed in response to a burrowing life style, it became suitable for many other ways of life. The extra ribs along the neck can be moved in waves, like the legs of a centipede, and allow the animal to crawl up very steep slopes. The bulbous body is pushed along behind by the hind legs. The treewyrm feeds on small insects and vertebrates.
The distribution of treewyrms is widespread, especially in the tropical forests of the Oriental realm, the animals having moved there across the deserts that form the boundary to the realm to the south-west of the great mountain chain.

The paraso, unlike other fishing pterosaurs, is a solitary animal, flying and hunting on its own (a). Its head and jaws are very slim, with many tiny sharp teeth (b). These teeth are typical of a fishing animal, being able to grip slippery fish firmly.

The glub is totally adapted to life in the water. Its eyes and nostrils are on the top of the head to allow it to see about on the surface while the body is submerged. The front legs have paddles and a long claw for digging up the roots of the water plants on which it feeds.

Demonstrating its unique fishing action, the paraso wades in the open shallow waters and holds its wings out in a huge fan in front, casting a large shadow over the water. This has two results. First, the fish actively seek out this welcoming shade to escape from the glare of the sun and second, the paraso can see and catch the fish without the distracting reflections on the surface of the water.

 

Mixed woodlands – swamp

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GLUB

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Lutasaurus anacrusus

A very specialized plant life grows in the waters of the mangrove swamp. It must be able to withstand inundation by muddy fresh water at times of flood, and by salt water at high tides. It must also be able to grow in the shifting muds brought down by the rivers. The mangroves can do this, securing their roots in the mudbanks to anchor the sediments and build them up into permanent parts of the landscape. The roots often protrude above the level of mud and water to help the plant to breathe, there being little oxygen in the mud of the swamp.
In the water there are many other varieties of plants, and these are consumed by a number of different animals. The largest is the glub, a descendant of the adaptable hypsilophodonts. It is similar in appearance to the watergulp of the tropical river swamps in the Neotropical realm (page 68), also evolved from a hypsilophodont. The resemblance is a case of parallel evolution, in which two related creatures have developed along the same lines in response to similar environmental conditions. The evolution took place independently, on opposite sides of the world. In the glub, the process has gone even further than in the watergulp. The whole body of the glub, all 2 metres (6 ft) of it, has become a swimming organ. Sinuous, lateral movements of its body and tail, aided by the tall fin down the back, drive the animal forward through the water. It steers itself by its forelimbs. The hind limbs have totally atrophied.

Mixed woodland – swamps

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PARASO

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Umbrala solitara

Vast areas of tropical swamp and deltas are found in the Oriental realm, where great rivers, fed by the snow and glaciers of the mighty mountains, wander across the lowlands and empty into the ocean. Mangrove swamps develop at the sea’s edge on the mudbanks built up by debris deposited by the rivers. The mangrove swamp usually blends into the tropical forest on the drier land, and many of the tree creatures that live here are the same as those further inland.
The swamps are home to a great many fish and aquatic animals, particularly those that can withstand the conditions of both salt water and fresh water. They also support vast numbers of wading birds and pterosaurs that feed on the fish and the mud creatures. The paraso is one of the oddest of such animals. It is a pterosaur that hunts in the shallow lagoons and backwaters of the swamps. It is quite large, with a wingspan of about 3 metres (10 ft). The wings are brightly coloured and make a dazzling display as the pterosaur launches itself into the air and flies off over the swamp. The wings, however, have another function. They are used as a kind of a trap in order to lure and catch fish in a way that is totally unlike any other in the animal kingdom.