Ape, a quadrumanous animal of the class mammalia, nearly approaching the human race in anatomical structure. A common distinction between the monkey, baboon, and ape is. that the first has a long and prehensile tail, the second a short one, and the third none at all. According to the modern zoological definition, however, the genus ape, or pithecus, comprises those quadrumanous mammals which have the teeth of the same number and form as in man, and which possess neither tails nor cheek pouches. This definition, while it excludes certain tailless baboons and monkeys, comprehends the three sub-genera of orangs, chimpanzees, and gibbons. Their arms almost touch the ground when they stand erect on their hind legs; but the legs are scarcely a third part of the entire height. The legs are not on the same line with the thighs; the knees are turned outward, and the soles of the feet turn inward, so as to be opposed to one another. The apes are thus enabled to grasp the trunks of trees with much greater force than if their members were constructed like man's. The fingers and toes are long, flexible, and deeply separated from one another; and the thumb, or anterior finger, is completely opposite to the other four, as well on the hind as on the fore limb.

Thus their hands and feet are equally well formed for grasping, and can be used indiscriminately. Hence, apes are neither two-legged and two-handed, like the human race, nor four-footed, like quadrupeds, but four-handed (quadrumanous). When they walk erect, which they rarely do without the aid of a staff or of their forearms, owing to the oblique articulation of the lower extremities, they rest only on the outer edge of the feet. This gives them a tottering and uncertain motion, to remedy which they place the fists of their long arms on the ground, and move in the attitude and at the pace of a lame man going on crutches. Consequently, while on the ground, they are slow, inert, and helpless animals, although in their native forests, passing from bough to bough and from tree to tree, they are the most agile of all creatures. - The character and habits of the great apes in a state of nature are little understood. Notwithstanding the gentleness and docility of those brought young from their native climates, there is reason to believe that in their native wilds they become as they grow old fierce, dangerous, and perhaps even carnivorous; for, although the number of their teeth and the formation of the molars and incisors precisely resemble those of the human being, the canines are developed in the same relative proportion as in the carnivora, so much so that the tusks of a full-grown orang-outang are fully equal to those of a lion.

In confinement, however, they are almost wholly free from the mischievous and petulant curiosity and violent fits of passion which characterize the smaller monkeys; are deliberate in their actions, circumspect, intelligent, and susceptible of a high degree of attachment to those who take care of them, or with whom they consort. They have two singular points of resemblance to man in their habits, which are worthy to be contrasted with the structural dissimilarities which have been insisted on above: 1. They do not repose, like the other monkeys, squatting on their hams, but stretch themselves on their sides, like human beings, and support their heads on their hands, or find some natural substitute for a pillow. 2. Alone of animals, they use other means of defence or attack than their own natural means, strength, and weapons, readily betaking themselves to the use of stones and clubs, which they wield with considerable dexterity, either hurling them as missiles, or using them hand to hand. In their mental powers, or intelligence, the apes in nowise approach the dog, the elephant, or the horse, although their natural facility of imitating human action has obtained for them the credit of approaching nearly to human comprehension. - See Chimpanzee, Gibbon, Gorilla, and Orang-Outaxg.