The Gorilla is limited in its distribution to the forest tract of the Gaboon. It goes about in families, with but one adult male, who later has to dispute his position as leader of the band with another male, whom he kills or drives away, or by whom he is killed or driven away. The animal is said to make a nest in a tree like the Orang; but this statement has been questioned.
It feeds upon the berries of various plants, and upon other vegetable substances; there is apparently not so marked an inclination for animal food as is exhibited by the Chimpanzee. In search of their food they wander through the forest, walking partly upon the bent hand, and progressing with a shuffling gait. It is noteworthy that the Gorilla has been said to walk upon the palm of the hand and not upon the back, as is the case with the Chimpanzee. It can readily assume the upright posture, and, in this case, balances itself largely with its arms. Professor Hartmann, however, states that the back of the hand is also used. Unlike most or many wild beasts, the Gorilla exhibits no desire to run away when he views a human enemy. Dr. Savage remarks that "when the male is first seen, he gives a terrific yell, that resounds far and wide through the forest, something like kh-ah! kh-ah! prolonged and shrill." This is accompanied by offensive tactics, which the natives do not willingly encounter. When making an attack the Gorilla rises to his feet, and as a full-grown animal reaches a height of some five feet, he is a most formidable antagonist. The attack of one of these animals is said to be made with the hand, with which he strikes his adversary to the ground, and then uses the powerful canines. The beating of the breast which heralds an attack is a statement made by M. du Chaillu. It has been denied with a vigour and asperity quite incommensurate with the importance of the matter.[[423]]
Fig. 275.—A, Cerebrum of a female Chimpanzee two years old. × ½. (Dorsal aspect, showing asymmetrical development.) c.c′, c.c″, Anterior and posterior central convolutions; f.i, interparietal fissure; f.l, the longitudinal fissure; f.po, parieto-occipital fissure; fr, frontal lobes; oc, occipital lobes; s.c, sulcus centralis. B, Brain of a female Chimpanzee two years old. × ½. (Lateral aspect.) cb, Cerebellum; c.c′, c.c″, anterior and posterior central convolutions; fr, frontal lobe; f.s, fissura Sylvii; is, island of Reil; md, medulla oblongata; oc, occipital lobe; pa, parietal lobe; s.c, sulcus centralis; tp, temporal lobe. (From Wiedersheim's Structure of Man.)
The Chimpanzees, genus Anthropopithecus (or Troglodytes), are
to be distinguished from the Gorilla by the characters mentioned in the account of the latter animal. Briefly summed up they are mainly as follows:—The ears are large, and generally stand out from the head; but there are exceptions to be noted
presently. The pigmentation of the body is not always so pronounced as in the Gorilla. The nasal bones are shorter. The skull as a whole is more brachycephalic, and the molar teeth are smaller. The hands and feet are much longer, the animal being more purely arboreal than the Gorilla. The female Chimpanzee is slightly smaller than the male, but the great disparity observable in the Gorilla does not characterise its ally. The animal, like the Gorilla, has large air sacs.
Fig. 276.—Skull of Chimpanzee. Anthropopithecus troglodytes. × ⅓. (After de Blainville.)
Chimpanzees are entirely restricted to Africa, and though they appear to extend rather farther east than the Gorilla, the forest-clad region of the equatorial belt is their home.