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What Might Earth's Wildlife Look Like if Humans Disappeared?

May 31, 2018 5:00 AMNov 20, 2019 10:13 PM


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In "After Man", author Dougal Dixon blends his passionate interest in geology and zoology with incredible illustrations to imagine a beautiful, radically altered, and not wholly undesirable reality in which mankind is wiped out, but evolution surges on. Originally published in 1981, it is THE seminal work of speculative biology. While the animals depicted seem wildly fantastical at first, Dixon’s detailed descriptions of how evolutionary quirks could lead to the genesis of such creatures lends an unusual and appealing feeling of excitement and possibility.

Check out an excerpt of this fantastic world here, complete with original illustrations.

Designed to resemble the sumptuous encyclopaedias of yesteryear, "After Man: A Zoology of the Future" is available now from Breakdown Press. Order your copy here: www.breakdownpress.com.

The elephants flourished throughout the first half of the Age of Mammals, but with man's appearance their numbers fell until they had almost become extinct. Two genera only, Elephas and Loxodonta, were latterly contemporaries of man and both of these died out shortly before man's disappearance, leaving no descendants. The ecological niche which they vacated was eventually filled by the descendants of a surviving group of antelopes, the gigantelopes. These enormous creatures with tree-trunk legs and weighing up to ten tonnes became the giant herbivores of the tropical plains, a group of animals feeding on trees, grasses or roots depending on the species. They had long since abandoned the antelope's running gait and had instead taken up a plodding existence — the two-toed feet of their ancestors having become broad-hooved pads.

The typical grassland-dwelling type, Megalodorcas giganteus, has four horns — one pair curving down behind its ears and another pair pointing out in front of its snout. Each horn has a pick-like point, enabling the animal to scrape soil away from the plant roots and bulbs on which it feeds.

The animal's basic shape was highly successful and in the course of time the gigantelopes spread northwards from tropical Africa, crossing the Himalayan Uplands in two separate waves of migration; one spreading into the coniferous forests and giving rise to the hornheads, Cornudens spp., and the other, much later, reaching the tundra. and providing the ancestors of the woolly gigantelope, Megalodorcas borealis.

At first glance these massive beasts seem to contradict the general rule that animals of hotter climates tend to be smaller than their equivalents in cooler areas. The larger an animal is, the smaller its surface area is in relation to its body mass, and the more difficult it is for it to lose excess heat. in the case of gigantelopes, however, this problem is overcome by the possession of a large dewlap beneath the neck, which is well served with blood vessels and effectively increases the creature's body area by about a fifth, thus providing an efficient heat radiator.

The rhinoceros, another of the massive tropical grassland animals that became extinct during the Age of Man, has an almost direct equivalent in the gigantelopes — the rundihom, Tetraceras africanus. It has adopted a body size and a horn arrangement not unlike its predecessor's and is a grazing animal, a fact that is reflected by its broad snout and muzzle. Its alarming horn array is used for defence, although the animal has few enemies likely to risk a frontal attack, For the males, however, its secondary function — for sexual display — is now more important.

The flora of the mountains has much in common with that of tundra regions because of the similarity in climatic conditions found there — low temperature, high precipitation and short growing season in both habitats.

The groath, Hebecephalus montanus, a variety of small hornhead frequently found grazing on grassy, south-facing slopes, lives in small herds of four or five females, guarded jealously by a male. The most apparent difference between males and females is in their horn structure. The males have flat, bony plate-like horns which they use to buffet one another in their frequent fights for herd dominance. The females' pointed pyramidal horns are much more deadly and are used to defend themselves and their young against predators. While the herd grazes, the male normally stands on a promontory watching for signs of danger. When it sees an intruder the male signals by erecting its long flag-like tail and the herd makes for the shelter of a nearby crag or cave.

One of the deadliest predators found in the African-European mountains is the shurrack, Oromustela altifera, a carnivore related to the weasel-like pamthret, Vulpemustela, of the northern coniferous forests. Sure-footed over difficult rocky terrain and well camouflaged by its mottled grey fur it is the groath's principal enemy. The shurracks hunt its packs, surrounding their prey, or cornering them in ravines, sharing the kill among themselves.

Although during the first half of the Age of Mammals South America did have a small population of primitive placental mammals, it was, like Australia, a bastion of the marsupials. However, just before the Age of Man, a land bridge was established between South American and North America, which led to an exchange of fauna between the two areas.The result was that the placental mammals from the north, being more versatile, almost entirely replaced the marsupials and primitive placentals of the south. The northern fauna were more versatile because they had been subjected to greater selective pressures in the preceding 50 million years; they had been compelled to adapt radically in the face of changing environmental conditions brought about by such factors as ice ages and faunal exchanges with Asia. The result at the time of the collision with South America was a very hardy and adaptable stock of animals. The mammals of South America, on the other hand, had experienced a stable unchanging environment during the same time period and therefore lacked this essential adaptability. A similar fate did not befall the marsupials of Australia, since that continent, in drifting northwards, presented its fauna with constantly changing conditions, resulting in a population of hardy species that were able to survive the faunal exchanges that occurred during the period shortly after Australia impacted with Asia.

Twenty million years after the Age of Man, the land connection with North America was once again broken and South America became an island continent once more. Since the split, climatic conditions on the South American continent have remained unchanged and the fauna has therefore changed very little. This conservatism is well seen among the mammalian predators — a niche that has continued to be occupied b y members of the order Carnivora despite the fact that this group has declined elsewhere.

The foremost predator of the South American tropical forest is the gurrath, Oncherpestes fodrhami, a giant hinting mongoose. its ancestor, Herpestes, was introduced by man to the then offshore islands at the north of continent where it became a pest and overran them. When the islands became fused to the mainland the mongoose spread southwards and developed into its present jaguar-like form. Its chief prey is the tapimus, Tapimus maximus, a long-tusked rodent that feeds in open areas of the forest.

Although the two principal predators of the tropical grasslands of the African sub-continent are both primates, they have both evolved along very different lines and hunt very different prey.

The horrane Phobocebus hamungulus, is descended from the tree-dwelling apes of the the tropical forests, a fact indicated by the way that than animals walks on the knuckles of its forefeet. It leads a totally ground-dwelling carnivorous mode of life. Lying in the long where it is camouflaged by its stripes and mane, it waits for uts chief prey, the gigantelopes. As they pass by, the horrane leaps out on to the back or neck of its quarry, using its sickle-like claws to rip deep wounds around the neck or throat. Severely wounded, the gigantelope soon dies, providing a meal for the whole horrane family group.

The other main predator is the raboon, Carnopapio spp. Descended from the baboons that flourished on the grasslands during the Age of Man, their diet changed from omnivorous to carnivorous during the period that the big cats of the grasslands died out. At the same time, they increased their speed by taking to their hind limbs and adopting a totally bipedal locomotion. The forelimbs became reduced and the head was carried further forward, balanced by a thick, heavy tail. In physical form, the raboon bears a distinct resemblance to the carnivorous dinosaurs that died out more than a hundred million years ago.

A number of species of raboon, each living on a different species of prey, exist in family-based tribes, the ancestral baboons. Carnopapio longipes is a very small, lightly built species about 1.8 meters high that hunts smaller animals. C. vulgaris is the most widely-ranging species and preys on the rabbuck herds. C. grandis is the most massive member of the genus. It stands about 2.3 meters high and the hip and lives purely as a scavenger. As predators such as the horrane eat only the softer tissues and muscles of the gigantelopes belly and anal regions, there is always plenty of meat left for the scavengers. The giant raboon concentrates on the meat of the limbs and neck, leaving the rest to smaller, less powerful carrion feeders.

The most efficient scavenger of the African grassland is the ghole, Pallidogale nudicollum, a creature that resembles a large mongoose. Its head and neck are almost totally devoid of hair, alowing it to reach inside the body cavities of carcasses without its coat becoming fouled. Its canine teeth are particularly huge and capable of crushing most bones to get at the marrow. Gholes live in packs of about a dozen and have developed an almost symbiotic relationship with a species of termite. This termite builds its mound with a horizontal shelf projecting out all round, a meter or so above the ground. The shelf itself provides shelter from the fierce midday sun where the ghole can bring bones and other tough parts of its meal to chew at leisure. The termites feed on the scraps of carrion that the ghole invariably leaves scattered around the mound, thus benefiting from the relationship. It usually takes about three days for the predators and scavengers of the grasslands to reduce a gigantelope to no more than a few pieces of bone and hide a patch of stained, trampled ground. The final remnants are consumed by insects and micro-organisms.

In comparison with other parts of the world, the animal and plant life of the tundra consists of a rather small number of species, each of which contains a relatively large number of individuals — a situation which is diametrically opposite to that found in the tropics. The low species count is entirely due to the region's inhospitable conditions. All tundra animals have evolved from creatures found in more temperate areas; their ancestors probably colonized the tundra only because they were driven to do so by fierce territorial competition. Life has to be unusually unpleasant elsewhere for a group of animals to venture into the tundra in the first place.

For many large animals the tundra is only habitable during the summer months and in winter they migrate southwards into the coniferous forests, where conditions are less austere. The largest of these animals is the woolly gigantelope, Megatodarcas borealis, a close relation of the tropical gigantelope. It differs mainly in size and in the possession of a large, fatty hump, which provides it with nourishment during the hungry winter months. It has a long, shaggy winter coat and broad hooves, which prevent it from sinking into soft snow. It uses its enormous horns as snow ploughs to expose the mosses, lichens and herbaceous plants on which it feeds. Its eyes are small to avoid being frost-bitten and its nostrils are bordered by blood vessels that warm the air before it reaches the lungs.

In early summer, the woolly gigantelope loses its shaggy coat and takes on a much sleeker appearance. The hump which sustained it through the winter months is now entirely depleted and it spends much of the time eating to rebuild its energy store for the long trek back south in the autumn.

Because of the woolly gigantelope's size — three metres at the shoulder without the hump — there are very few predators powerful enough to threaten it. Its only real enemy, the bardelot, Smilomys atrox, is a creature that would have been very much at home back in the first half of the Age of Mammals. At that time elephants, animals of comparable size to the gigantelopes, were preyed on by sabre tooths. These creatures, members of the cat family, had long, stabbing canine teeth with which they inflicted deep, stabbing wounds on their quarry. After an attack the sabre tooths would wait until the elephants bled to death before moving in to feed. This successful arrangement was even evolved independently among the marsupials. However, during the Age of Man the elephants declined and the sabre tooths, being entirely dependent on them, died out completely.

With the advent of the gigantelopes the sabre tooth pattern reappeared, but this time among the predator rats. The bardelot, unlike other members of the group, exhibits sexual dimorphism in that only the female is equipped with sabre teeth and hunts the gigantelopes. The male, having none, resembles more the polar bears that once inhabited these latitudes.

Plant-eating mammals abound in the trees of the deciduous forests, eating shoots and leaf buds in the spring and fruits and nuts in the autumn. The long-bodied squirrel, known as the chirit, Tendesciurus rufus, is a typical plant-eating mammal. Its peculiar shape is a legacy from an immediate ancestor — the tree-burrowing rodent of the northern coniferous forests. As it spread south into the temperate woodlands it found that it no longer needed to make deep tunnels in the trees to escape the harsh winter, and as a result the animal's specialized chiselling and gnawing teeth became smaller, its dentition reverting to be more like that of its distant ancestor the grey squirrel. Its bodily shape, however, was still perfectly adapted to life in the trees and remained unchanged.

Now that the animal no longer led a burrowing existence, its legs and feet had to evolve to suit its new environment. Its hind feet, although small and short, became very powerful and developed strong, gripping claws. The underside of its short tail grew hard and scaly and with its hind feet formed a strong three-point anchor that could secure the animal to the tree while it reached out to collect food.

As its squirrel ancestor's jumping ability has completely disappeared, the animal can only move from one tree to another by reaching out and grasping an extended branch. For this reason the chirit is found most often in dense thickets, where the trees are close together. Its only enemies are birds of prey, and it is really only vulnerable to these when feeding in the topmost branches. It retains the predilection of the burrowing squirrel for making nests in holes in trees and often occupies holes and hollows excavated by wood-boring birds.

The browsers are the largest animals living in the coniferous forest regions. They feed mainly on young twigs and needles in the summer and subsist on bark, mosses and lichens during the rest of the year.

Across the northern continent the most prolific species are those that are derived from the gigantelopes of the African sub-continent. These northern animals, although much heavier than their distant antelope ancestors, are still not nearly as huge as the African gigantelopes. Only the shaggy tundra-dwelling forms of the far north can compare in size with these.

Soon after their arrival in the coniferous forest the ancestral hornheads' jaws and horns began to evolve in response to their new environment. In common with all the now almost extinct ruminants, most of these creatures possessed no upper incisor teeth. They cropped grass by working their lower incisors against a bony pad on the roof of the mouth. However, this system is not particularly effective for browsing from forest trees. The first change that took place was that the horny head plate became extended forward to form a sort of beak. The lower lip became muscular and grew forward to meet it, thus extending the mouth some distance beyond the front teeth. This fairly primitive arrangement is still found in several species, for example the helmeted hornhead, Cornudens horridus. In more advanced forms, however, the lower jaw is also extended so that the lower front teeth meet the horny beak instead. These adaptations are the result of evolutionary pressure that enabled only those forms that could feed successfully on the twigs, bark and lichens of the coniferous trees to survive. The elaborate horn formation above the eyes is also used for defence.

The horn structure has been carried one stage further in the water hornhead, Cornudens rastrostrius, that inhabits lakesides and the banks of rivers. In this creature the horny plate extends forward into a broad rake-like structure, with which the animal grazes on soft water weeds that it finds on the beds of ponds and streams. It has two broad hooves on each foot, set widely apart and connected by a web of skin, which prevents the animal from sinking into soft mud and sand. The water hornhead, in its way of life, must surely resemble the hadrosaurs — the duckbilled dinosaurs of the latter part of the Age of Reptiles.

In the mammal world the predators were traditionally carnivores (members of the order carnivora) — specialized meat-eating animals with teeth modified for stabbing, killing and tearing flesh. Their legs were designed for leaping and producing a turn of speed that could quickly bring their chosen prey within killing distance. Wolves, lions, sabre-tooths, stoats — these were the creatures that fed on the docile herbivores and kept their numbers in check both during and before the Age of Man. However, being very specialized, these species tended not to have a great life span. They were so sensitive to changes in the nature and the populations of their prey that the average life of a carnivore genus was only six and a half million years. They reached their acme just before the Age of Man, but have since decreased in importance and are now almost extinct except for a number of aberrant and specialized forms found in the coniferous forest of the far north and in the South American Island Continent.

The place of the carnivores, as the principal mammal predators, is now occupied by a variety of mammal groups in different parts of the world. In temperate regions the descendants of the rodents occupy this niche.

In temperate latitudes the larger herbivores, the grazers and browsers of the plains and forests that were one time prey to the wolf, have now become the prey of the falanx, Amphimorphodus cynomorphus, a very large dog-like rat which hunts in packs. The evolution of this form involved the modification of the limbs from the fairly generalized scampering legs of the rat to very sophisticated running organs with small, thickly padded feet, and long shanks powered by strong muscles and tendons.

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