The predator rats are a group of carnivorous rodent from Dougal Dixon's After Man. They evolved from the rat, hence its name. After the age of man, the extinction of most carnivorans made the rat, have a chance to take over their niches. In the distant future, they diversified, having to take the place of the ordinary mammal carnivores - lions, tigers, wolves, weasels even seals and walruses - and evolved a similar form, although they have retained primitive features, like a long hairless tail.
History of Predator RatsEdit
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 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 peak 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 (see the gurrath and the striger).
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. When the carnivores were at their peak, the rodents, particularly the rats, began to acquire a taste for meat and animal waste. The spread of man to all parts of the world encouraged their proliferation and after man's demise they continued to flourish in the refuse created by the disruption and decay of human civilization. It is this adaptability that has ensured their survival. Despite the specialized nature of their teeth, rats were able to live on a wide range of foods. At the front of their mouths they had two sharp gnawing incisors, which continued to grow throughout life to compensate for wear and which were separated by a gap from the back teeth. These were equipped with flat surfaces for grinding vegetable matter. This is very different from the typical carnivore dentition, which had cutting incisors at the front followed by a pair of stabbing canines and a row of shearing teeth at the back.As the rats expanded to occupy the niches left by the dwindling carnivores their teeth evolved to fulfil their new role. The gnawing incisors developed long, stabbing points and were equipped with blades that could cut into and grip their prey. The gap between the incisors and the back teeth became smaller and the grinding molars became shearing teeth that worked with a scissor action. To make the dentition effective the jaw articulation changed from a rotary grinding motion into a more powerful up-and-down action. This dentition was crucial in the development of the predator rats and allowed them to radiate into the numerous forms and varieties seen throughout the world today. 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.
A particular group of predator rats specialized to life in the arctic seas, developing fins, smooth skin and tail flukes. Examples of this lineage are the seal-like pytheron, Thalassomus piscivorus, and the bulkier, walrus-like distarterops, Scinderedens solungulus.
Species of Predator RatsEditThe falanx (Amphimorphodus cynomorphus) is the most common species of predator rats found in temperate latitudes and the largest member of the family. Although superficially dog/like in form, its rat ancestry is quite unmistakable. The falanx are the rabbucks' principal predators. They hunt in small packs, singling out the weaker individuals and harrying them to exhaustion. The dentition of the ancestral rat, consisting in gnawing incisors and grinding teeth reflects its herbivorous origins; in contrast the predator rats have stabbing incisors followed by a row of shearing teeth.
The rapide (Amphimorphodus longipes), a native of the northern plains, is built for speed. Its highly flexible spine gives it the added impetus to reach speeds of over 100 kilometers per hour. It's falanx's nearest parent.
The ravene (Vulpemys ferox) is about the size of the extinct fox or wild cat and preys on small mammals and birds. It has long claws and pointed stabbing fangs.
The polar ravene (Vulpemys albulus) differs from its temperate woodland cousin as it has a smaller head with tiny eyes and ears (an adaptation that prevents frostbite) and long, dull brown fur that turns white in the winter to camouflage it against the snow. It attacks the meaching (rodents of northern tundra) by digging into the fortress with its front paws.The janiset (Viverinus brevipes) is a long-bodied, burrowing predator, strongly resembling the extinct stoats and weasels, and like them will swim, climb trees and tunnel underground in pursuit of its prey.
The bardelot (Smilomys atrox) of the arctic plains resembles a polar bear, but bardelot females have big sabre teeth formed from the outer crown of their incisors and big skin pouches to hide them. Females use their sabres to attack woolly gigantelopes, inflicting deep stabbing wounds on their quarry and waiting until the prey bleeds to death. The males have no sabres and preys smaller animals.
The existence of predator rats has been strongly criticized. Dixon eliminates almost all carnivores--including coyotes, which are effectively impossible for humans to eradicate; cats, which are some of the most invasive species ever and are well liked by humans; and the American mink, which are listed by the IUCN as Least Concern and stable. Not limiting ourselves to North America, we find many other species that would have to be driven extinct, many of which are doing perfectly well.
- ↑ Fraser, Caroline. (1999). Rewilding the World: Dispatches from the Conservation Revolution. New York City: Metropolitan Books.
- ↑ The Commonwealth of Australia. (2011). The Feral Cat (Felis catus) - Fact Sheet. Retrieved from http://www.environment.gov.au/biodiversity/invasive/publications/pubs/cat.pdf.
- ↑ Reid, F. & Helgen, K. (2008). Neovison vison. Retrieved from http://www.iucnredlist.org/details/41661/0.