Animals, especially mammalia, with which chiefly we are concerned, were, at the close of the Oligocene, very different from any that now roam the lands; all the species, most genera, many families and some whole orders have since disappeared. But there were plenty to eat and a good many to dread. Until we know the neighbourhood in which our ape’s adventures began, nothing precise can be said of his circumstances. Probably it was somewhere in the Old World, and probably it was in Asia. Unfortunately, we know nothing of the zoological antiquities of Asia until the early Miocene, and even then a very small selection of what must have existed, because geologists have hitherto explored a very small part of the continent—a few beds in north-western and northern India and in Burmah. But there is so much evidence of the migrations of animals in successive ages of the Tertiary Period, that any remains from the Oligocene and Miocene will help us to understand what sort of neighbours our remote ancestors had to live amongst. For prey there was great variety of birds and reptiles (everywhere eaten by savages) and fishes; but we are most concerned with the mammalia, which he may be supposed to have pursued afoot. Of these the most important are the hoofed animals, which fall into two great groups, perhaps not closely connected—the odd-toed (Perissodactyls) and the even-toed (Artiodactyls). During the Oligocene there lived in Europe, or in North America, or in both—and, therefore, probably in Asia—numbers of the odd-toed group: tapirs; rhinoceroses of several species, some without horns, some with, some amphibious (Amynodonts), all smaller than their modern representatives; chalicotheres, strange beasts something like horses, but instead of hoofs they had claws on their toes—perhaps survived in China into the Pleistocene; small predecessors of the horse with three toes on each foot; titanotheres, hugest animals of their age, extinct in the middle of it—something like the rhinoceros and nearly as big as an elephant (_Brontotherium_). Of the even-toed group, pig-like animals abounded, and some true pigs appeared; entelodonts, or giant-pigs, were common; anthracotheres, somewhat pig-like in size and shape; ancestral camels about the size of sheep were to be had in North America; oreodonts, unfinished-looking creatures of many species; primitive deer and other ruminants, small in size and not having yet grown any horns. In Europe, during the Upper Oligocene, cœnotheres, small and graceful animals, lived in large herds around the lakes. There were also primitive proboscidia about half the size of modern elephants; many insectivores; and, amongst rodents, beavers and tailless hares. Generally, animals of this age that have left descendants were smaller than their modern representatives; and notably their brains were smaller.