Chapter VII: The Siamang Gibbon. Hylobates Syndactylus

_Pithecus syndactylus_, Desmar., Mamm., p. 531 (1820).

_Hylobates syndactylus_, F. Cuv., Hist. Nat. Mammif., pl. iv. (1821); Is.
Geoffr., Cat. Méth. Primates, p. 9 (1851); Bennett, Wanderings in N. S.
Wales, ii., p. 151 (1834); Martin, Mammif. An., p. 420 (1841); Flower,
Nat. Hist. Rev., 1863, p. 279 (cum fig.); Giebel, Z. Ges. Nat., p. 186
(1866); Schl., Mus. Pays-Bas, vii., p. 22 (1876); Anderson, Zool. Res.
Exped. Yun-nan, p. 10 (1878; with full synonymy).

_Simia syndactylus_, Raffl., Tr. Linn. Soc., xiii., p. 241 (1822).

_Siamanga syndactyla_, Gray, Cat. Monkeys Brit. Mus., p. 9 (1870), id.,
_op. cit._, p. 9 (1870); H. O. Forbes, Nat. Wand. East. Arch., p. 129
(1885).

(_Plate XXXVIII._)

CHARACTERS.--This is the largest species of the genus, measuring more than three feet; it is stouter than _H. hoolock_, and its hair is entirely glossy black, having no white hairs anywhere; the face is black, as is also the distensible skin of the large bare patch on the throat, which overlies its great laryngeal pouch. The second and middle toes are united by a web as far as the last joint. The hair on the arms and fore-arms converges towards the elbow.

The skulls in most of the species of this genus closely resemble each other; that of the Siamang is distinguished by its larger size, and in having the supra-orbital ridges more developed, while the occipital region is more truncated, and there is at the symphysis of the lower jaw a true, though slight, chin.

PLATE XXXVIII.

{167}The frontal lobes of the brain are broad and much flattened, and not full and rounded as in the Orang. The olfactory bulbs project forward, slightly beyond the frontal lobes of the cerebrum; the occipital lobes are much reduced, while the large cerebellum projects distinctly backwards from below the cerebrum--characters in which this very highly organised member of the genus shows a retrogressive development, thus differing from all the other Man-like Apes, in all of which the cerebrum entirely covers both the olfactory lobes in front, and the cerebellum behind.

The large laryngeal sac, communicating by two openings with the larynx, and formed by the extension of the thyro-hyoid membrane, distinguishes this from all the other Gibbons.

DISTRIBUTION.--The Siamang is confined to the island of Sumatra. It has been recorded from Malacca and Tenasserim; but some doubt exists as to the accurate determination of the individuals referred to, no really authentic specimen having yet been obtained out of Sumatra.

HABITS.--The Siamang is gregarious, frequenting the great forest-trees from 200 to 300 feet above the sea up to 3,000 or 4,000 feet.

I made the acquaintance of this species in Southern Sumatra, and during my stay in that island had various opportunities of observing many of them in their homes. It was not uncommon to come suddenly on a colony of them both in the forest and among the tall isolated outliers, when they happened to be covered with fruit. The satiated members of the company {168}might then be often seen hanging by one arm from a bare branch, with perhaps eighty unobstructed feet between them and the ground, making the woods resound with their loud barking howls, uttered apparently for pure love of making a noise. On one occasion a young one, found clinging to its mother, which had been shot, was brought in alive. It had been only stunned by a pellet on the head, and had no bones broken. In a very short time it became a most delightful companion. The following observations in reference to it are taken from the writer's Journal: "Its expression of countenance is most intelligent and often very human; but in captivity it generally wears a sad and dejected aspect, which quite disappears in its excited moods. With what elegance and gentleness it takes with its delicate taper fingers whatever is offered to it! Except for their hairiness, its hands, and, in its youth at all events, its head, seem to me more human than those of any other Ape's. It rarely, however, brings its thumb into opposition with the other fingers, but usually clasps the whole hand, without that digit, on an object. It will never put its lips to a vessel to drink, but invariably lifts the water to its mouth, by dipping in its half-closed hand and then awkwardly licking the drops from its knuckles. It generally sits with its arms crossed over its chest, and its fingers overlaid behind its head. The gentle and caressing way in which it clasps me round the neck with its long arms, laying its head on my chest, and watching my face with its dark brown eyes, uttering a satisfied crooning sound, is most engaging. Although it often inflates its laryngeal sac, it rarely gives utterance to more than a yawn-like noise or suppressed bark; but this dilatation has no reference apparently to its good or bad temper, although, when very eager and {169}impatient for anything, a low pumping bark is uttered. Every evening it makes with me a tour round the village square, with one of its hands on my arm. It is a very curious and ludicrous sight to see it in the erect attitude on its somewhat bandy legs, hurrying along in the most frantic haste, as if to keep its head from outrunning its feet, with its long free arm see-sawing in a most odd way over its head to balance itself, and now and again touching the ground with its finger-tips or its knuckles. That they can leap the great distances from tree to tree ascribed to them is no doubt an accurate observation; but they appear to be sometimes terror-stricken and unable to perform these feats to save their lives. During the felling of the forest near this village, a small colony of Siamangs got isolated on a tree separated from the next clump by some thirty feet or so. They scampered up and down in the crown of the tree howling in the most abject terror at every stroke of the axe; yet they would not venture to leap the intervening space, and even, when the tree was falling, they did not attempt to save themselves by springing to the ground, but perished in its downfall.

"When teething my companion suffered severely--as the human infant so often does--both locally and constitutionally, as indicated by boils and inflamed finger-tips. On lancing and poulticing the latter, and extracting some of its obstructing teeth, the poor creature seemed greatly relieved, and I was delighted to watch it recover, without contracting for me any antipathy for the pain I had inflicted on it, but rather the reverse." At a later date the following extract occurs:--

"During my march to the coast my Siamang accompanied me, occupying, with the most grave demeanour, a seat on one of the packages carried in the rear, near to myself. Here it {170}sheltered its head, to the amusement of all whom we met, under a Chinese umbrella, which I had bought for it to protect it from the midday sun, and for which, after every halt, it held out its hands in the most knowing way, screaming lustily if the porters dared to move on before it had comfortably arranged itself. To my intense regret, a misadventure put an end to a most charming existence, before I could send it to London."

THE ORANG-UTANS. GENUS SIMIA.

_Simia_, Linn., Syst. Nat., i., p. 34 (1766); Erxl., Syst. Régne An., p.
6 (1777; part).

_Pithecus_, Geoffr., Ann. Mus., xix., p. 87 (1812); Huxley, Anat. Verteb.
An., p. 403.

_Pongo_, Geoffr., Ann. Mus., xix., p. 89 (1812).

This genus contains one species, well known as

THE ORANG-UTAN. SIMIA SATYRUS.

_Simia satyrus_, Linn., Syst. Nat., i., p. 34 (1766); Kuhl, Beitr. Zool.,
p. 4 (1820); Schreb., Säugeth., i., p. 54, pls. 2, 2 B. (1775); Fischer,
Syn. Mamm., p. 9 (1829); Owen, Tr. Z. S., i., p. 344, pls. 49, 53-56
(1835); Wallace, Malay Archip., i., p. 62 (1869); Gray, Cat. Monkeys
Brit. Mus., p. 8 (1870); Schlegel, Mus. Pays-Bas, vii., p. 9 (1876).

_Simia agrias_, Schreb. Säugeth, i., pl. 2, ii. B et ii. C (1775).

_Pongo wurmbii_, Geoffr., Ann. Mus., xix., p. 89 (1812); Kuhl, Beitr.
Zool., p. 21 (1820).

_Papio wurmbii_, Latr. Singes, i., p. 196.

PLATE XXXIX.

{171} _Pithecus satyrus_, Blumenb., Abbild., Naturh. Geg., fig. xii.
(1810); Geoffr., Ann. Mus., xix., p. 88 (1812); Latr., in Buff. Hist.
Nat., xxxv., p. 166, pl. 3; xxxvi., p. 276; Cuv. et Geoffr., Hist. Nat.,
Mamm., livr. xlii.; Desmar., Mamm., p. 50 (1820); Martin, Mammif. Anim.,
p. 388 (1841); Owen, Tr. Z. S., iv., p. 82, pl. 29 (1862).

_Simia wurmbii_, Kuhl, Beitr. Zool., p. 21 (1820); Fischer, Syn. Mamm.,
p. 32 (1829); Owen, Tr. Z. S., ii., p. 165, pls. 30-32 (1841); Brooke, P.
Z. S., 1841, p. 55 (Mias Pappan).

_Pithecus wurmbii_, Owen, Tr. Z. S., iv., p. 95, pl. xxxiii. (1862).

_Pongo abelii_, Clarke, Asiat. Res., xvi., 489 (1826); id., Edinb. Phil.
Journ., p. 375 (1827).

_Simia abelii_, Fischer, Syn. Mamm., p. 10 (1829; Sumatra).

_Simia morio_, Owen, P. Z. S., 1836, p. 92; id., Tr. Z. S., ii., p. 168,
pls. 33, 34 (1838); Brooke, P. Z. S., 1841, p. 55 (Mias Kassar); Wallace,
Malay Archip., i., p. 84 (1869); Sclater, P. Z. S., 1891, p. 301;
Beddard, Tr. Z. S., xiii., p. 20 (1893; Sumatra and Borneo).

_Pithecus morio_, Martin, Mammif. An., p. 395 (1841).

_Simia gigantica_, Pearson, J. A. S. Beng., x. (2), p. 660 (1841).

_Pithecus bicolor_, Is. Geoffr., Arch. Mus., Paris, ii., p. 526 (1841;
Sumatra).

_Pithecus owenii_, Blyth, J. A. S. Beng., xxii., p. 375 (1853).

_Pithecus curtus_, Blyth, _op. cit._, xxiv., p. 525 (1855).

(_Plate XXXIX._)

CHARACTERS.--The Orangs are large and heavy in build, with the head set on a very thick neck, the hair long and directed forward, and the abdomen round and protuberant. The naked face is melancholy. On each side of the face there is, in the {172}full grown male, but not in the female, a large, soft, smooth tumour-like and flexible expansion, which gives a remarkable breadth to the visage. The forehead is nude and purplish in colour; the middle of the face across the nose is sooty-brown. The lips are broad, extremely mobile, and of the colour of the skin--generally of a yellowish brown; and, when eating and drinking, the animal thrusts them far out. The lower jaw retreats at once from the lips, and there is therefore no chin, as so recognised in Man. The ears are more like those of Man, small and flat. The arms are very long, reaching to the ankles in the erect posture, their span being twice the animal's height. The arm is equal in length to the fore-arm; the hands are long and narrow. The fingers are united by a web; the thumb short and often without its terminal joint. The back of the hand is but slightly haired. The hair on the arm is directed downwards and that on the fore-arm upwards, so as to meet at the elbow. The legs are very short and bowed at the ankles; the long and narrow foot, which is articulated obliquely to the leg, is longer than the hand and (except in the Gorilla) is longer than in any other Ape. The great-toe is very short and is often destitute of a nail.

The cranium is very variable in form; the crown is high and pointed, the forehead round and elevated, and the occipital region convex. No two individuals are exactly alike. "The slope of the profile, the projection of the muzzle, together with the size of the cranium, offer differences as decided as those existing between the most strongly marked forms of the Caucasian and African crania in the human species. The orbits vary in width and height; the cranial ridge is either single or double, either much or little developed, independent of age, being sometimes more strongly developed in the less {173}aged animal." (_Wallace._) The supra-orbital ridges are prominent, without being particularly so. The contour of the head is more human in form, however, in youth than in age, when the forehead is large and convex. The canine teeth are very large and tusk-like in the male, but smaller in the female. The upper molars exhibit on their crowns complex rugosities; they have four cusps and an oblique ridge, as in Man, from the front inner, to the hind outer, cusp; the lower molars are five-cusped. The permanent canine teeth sometimes appear before the last permanent molar has come into place.

The thigh-bone (_femur_) has no round ligament binding its articular head into its socket in the pelvis, a disposition which, while it affords greater flexibility and freedom to the hind-limbs in climbing, gives it much less firmness in walking on the ground. The proportionate length of the foot to its limb is greater in this genus than in any other of the _Anthropoidea_. The ankle (_tarsus_) is very short, and the bones (_phalanges_) of the toes form the longest part of the foot. The great-toe is especially short and divergent, its terminal bone being often absent, while the bones of the digits are long and curved. On account of the form of certain bones of the tarsus and their inter-mobility the foot is set obliquely to the leg through the action of one of its muscles (the _tibialis anticus_), so that the sole is pulled to the inside when walking. The outer edge of the foot, with the upper side of the fourth and fifth toes, is therefore applied to the ground in the act of progression, while the spread thumb supports most of the animal's weight. The wrist (_carpus_) contains the complete number of nine bones, as it possesses the _os centrale_ wanting in Man and the Chimpanzees.

The breast-bone in the Orang is composed of ossifications {174}arranged in pairs, instead of being formed of only two bones, as in the other members of the family.

Between the neck and the complex and solid sacral bone there are sixteen vertebrae, and there are twelve pairs of ribs, as in Man. The vertebral column presents slight but distinct indications of the curvature so characteristic of Man, and is nearly as much concave forward in its dorso-lumbar region as in a child.

The Orang-utan has no uvula as in Man and in the Chimpanzees. It possesses enormous air sacs--dilatations of the lateral cavities (ventricles) of the larynx, found in Man--which extend over the throat, the top of the chest, and as far as the arm-pits; these may even unite in the middle line. Its great-toe and thumb lack the long flexor muscles which are present in Man and in the Chimpanzees.

"Of all Apes, the Orang has the brain which is most like that of Man; indeed, it may be said to be like Man's in all respects, save that it is much inferior in size and weight, and that the cerebrum is more symmetrically convoluted and less complicated with secondary and tertiary convolutions." (_Mivart._) The cerebral hemispheres are higher in proportion to their length than in any other _Anthropomorpha_, but they are elongated and depressed, as compared with Man. (_Huxley._)

The colour of the hair of the Orang is a brick- or yellowish-red all over, but in old males it is sometimes darker on the limbs. Its length (twelve to sixteen inches) is greatest, and its character coarsest, on the arms, thighs, and shoulders; the face, ears, and throat are bare, and the skin of a reddish- or yellowish-brown colour; but there is a thin beard on the chin. The back of the hand and fingers are also thickly haired; on {175}the arms the hair grows towards the elbow, as on the fore-arm, both meeting in a point at the elbow.

Between childhood and middle age the skin varies in colour from dark yellowish in the younger individuals to blackish-brown, or black, in the adults (the latter colour largely predominating). Very often the face and neck are almost or quite black, the palms light brown, and the breast and abdomen mulatto-yellow. (_Hornaday._)

In size also the Orang varies greatly; the males being larger than the females. The largest male shot by Wallace measured 4 feet 2 inches. Hornaday, however, shot several exceeding 4 feet 4 inches, his tallest being 4 feet 6 inches, and one male was 3 feet 10½ inches; while his largest female measured 4 feet, and the smallest adult female 3 feet 6 inches. The breadth across the face in males varies from 11½ to 13½ inches, and in females 5½ to 6 inches. The young at birth is large in comparison with the size of the female. A male weighs often from 120 to 160 lbs.

DISTRIBUTION.--The Orang-utan is confined to the islands of Borneo and Sumatra, in the East Indian Archipelago. In Sumatra it is far less common than in Borneo, and is found on the lowlands of the eastern coast, in the Palembang Residency, and the Djambi Sultanate. As far as I could ascertain, the natives of the southern portion of Palembang and of the Lampongs were quite ignorant of the animal, except as a name. In Borneo it inhabits the low forest-covered swamplands between the coast and the interior mountains, from the north of the island, round the west, southern, and eastern coasts, as far as the Mahakkam river, if not round the entire coast, as is most likely. In the dry season they retire into the {176}depths of the forest. In the fruit season they come nearer to the coast, while at the height of the rains they frequent the river banks.

HABITS.--The Orang-utan, the "forest-living Man" of the Malays, and the "Mias" of the Bornean natives, lives solitary in the leafy tops of the trees in the forests, except at the pairing season. A female is generally accompanied by one of her progeny, sometimes by two, the one always an infant, and the other a more or less grown but immature individual of a previous birth; for her young--of which she has only one at a birth--do not shift for themselves before they are approaching two years of age. At what age they attain maturity is unknown, but it is probably not before twelve to fifteen years. The infant clings by its arms to its mother when she is climbing, by grasping the hair of her arm-pits, while its legs embrace her sides above the hip. As already observed, the Orangs have none of the marvellous agility of the Gibbons. They are slow and deliberate in their movements; "surprisingly awkward and uncouth," according to Sir James Brooke; but their long and extremely powerful arms and hook-like fingers, which close with an amazing rigidity of grip, and their mobile legs and hand-like feet, enable them to lift and swing their bodies with great precision from branch to branch and tree to tree. "I have frequently seen them," says Hornaday, "swing along beneath the large limbs as a gymnast swings along a tight rope, reaching six feet at a stretch. When passing from one tree to another, the Orang reaches out and gathers in its grasp a number of small branches that he feels sure will sustain his weight, and then swings himself across." On the ground all this is very different. He walks very badly and unsteadily; he uses his arms as crutches, leaning his weight upon them with his fingers as already described, and {177}swings himself forward on them. On the ground the Orang does not move, according to Sir James Brooke, so fast as to preclude a man keeping up with him easily through a clear forest. "The very long arms, which, when he runs, are but little bent, raise the body of the Orang remarkably, so that he assumes much the posture of a very old man bent down by age, and making his way along by the help of a stick." (_Huxley._) The Orang, however, rarely comes to the ground of his own accord.

Mr. Martin gives the following account of a specimen which lived in the Zoological Gardens in London many years ago:--"Its attitudes were as varied as can be imagined, its actions slow and deliberate; excepting, indeed, on one or two occasions when it wished to follow its keeper, who had opened the door of its cage; even then it did not bound from branch to branch like a Monkey, but stretching out its arms, and grasping the branches within its reach, it swung itself onward, and so descended to the floor, along which it hobbled awkwardly and unsteadily. One thing, as respects both the hands and feet of this Orang, could not be overlooked; namely, that their mode of application to the branches, during the arboreal evolutions of the animal, was hook-like; and, from the power of the adductor muscles of the thumb, and flexor muscles of the fingers, tenacious and enduring, rather than tight and fixed. This observation is especially applicable to the feet; in these the shortness of the thumb, though capable in itself of firm and close application, renders it rather a fulcrum, against which the long fingers oppose their stress, than, by folding upon them, an adjunct to them in the act of prehension; and hence, though admirably fitted for the movements of the animal among the trees of the forest, and the kind {178}of hold necessary for freedom and security, the foot of the Orang is, perhaps, less energetic in the grasp than that of the semi-arboreal Chimpanzee, in which the hind-thumb is proportionately longer, and the foot broader, than in the Orang."

The Orang drinks by dipping its fingers into the water, as the Siamang does, and sucking the water off its knuckles, or dropping it into its protruded trough-like lower lip.

"The rude _hut_ which they are stated to build in trees, would be more properly called a seat or nest, for it has no roof or cover of any sort. The facility with which they form this nest is curious, and I had an opportunity of seeing a wounded female weave the branches together and seat herself within a minute." (_Sir James Brooke._) "The Orang usually selects," writes Mr. Hornaday, "a small tree, a sapling, in fact, and builds his nest in its top, even though his weight causes it to sway alarmingly. He always builds his nest low down, often within twenty-five feet of the ground, and seldom higher than forty feet. Sometimes it is fully four feet in diameter, but usually not more than three, and quite flat at the top. The branches are merely piled crosswise. I have never been able to ascertain to a certainty, but it is my opinion that an Orang, after building a nest, sleeps in it several nights in succession, unless he is called upon to leave its neighbourhood." In this nest he sleeps during the night or lies spread out on his back during the day, with his hands and feet grasping the nearest branches. The food of the Orang-Utan--whose eating-time is during the middle of the day--consists of leaves and nuts, especially of the durian, the rambutan, and the mangosteen.

The Orang-Utan is of a very shy and uncertain disposition. If captured when full-grown, it is wild and ferocious; when {179}young it is easily trained; but never lives in captivity to attain maturity. When attacked and hard driven by human enemies, and it gets to close quarters with them, it can be a formidable and dangerous antagonist, and has been known to fatally injure its assailants. It will rarely, unprovoked, attack a man. "In one case," as Dr. A. R. Wallace has recorded, "a female Mias on a durian-tree kept up for at least ten minutes a continuous shower of branches and of the heavy spined fruits as large as 32-pounders, which most effectively kept us clear of the tree she was on. She could be seen breaking them off and throwing them down with every appearance of rage, uttering at intervals a loud, pumping grunt, and evidently meaning mischief." They fight and defend themselves with their hands, and appear to seize and bite each other's fingers. Many of the specimens shot in the forest of Borneo have lost one or more of their fingers or toes; and present scars on the face (especially on the lips) and bodies from the teeth of their antagonists.

"When wounded he betakes himself to the highest attainable point of the tree, and emits a singular cry, consisting at first of high notes, which at length deepen into a low roar, not unlike that of a panther. While giving out the high notes, the Orang thrusts out his lips into a funnel shape; but in uttering the low notes he holds his mouth wide open, and at the same time the great throat bag, or laryngeal sac, becomes distended." (_Huxley._)

The name given by the Dyaks to the larger species is "Mias Pappan." There is, however, a smaller variety, which they designate "Mias Kassu," of which Dr. Wallace has given an excellent and detailed account. These Mias Kassu have no tumour-like expansions on the sides of the head; the median crest is {180}absent from the skull, for the muscular ridges remain some distance apart; the teeth are very large, especially the canines and the middle upper incisors. The females, which are smaller than the males, are also without the cheek-swellings and the prominent crests of the male, and have smaller canine teeth. This variety, named _Simia morio_ by Sir R. Owen, bears a close similarity to that found in Sumatra. It has been considered a distinct species both by Owen and Wallace, but the variation, as the latter naturalist himself admits, is so very great in just those characters which have been considered to separate "Mias Kassu" from "Mias Pappan," that it is highly probable that both are of the same species, but of different ages. Mr. Beddard found that an Ape exhibited in the Zoological Gardens as an adult example of _S. morio_ was in reality immature.

THE GORILLAS. GENUS GORILLA.

_Troglodytes_, Geoffr., Ann. Mus., xix., p. 87 (1812).

_Gorilla_, Is. Geoffr., C. R., xxxiv., p. 84, note (1852).

This genus, like the preceding, contains but a single species,

THE GORILLA. GORILLA GORILLA.

_Troglodytes gorilla_, Wyman, Bost. Journ. Nat. Hist. (2), v., p. 419,
pls. 1-4 (1847); Winwood-Reade, P. Z. S., 1863, p. 171; Owen, Tr. Z. S.,
ii., p. 381; v., pp. 1, 243, pls. i.-xiii., and xliii.-xlix; Scl., P. Z.
S., 1877, p. 303; Cunningham, Mem. Roy. Irish Ac., p. 1 (1886).

_Gorilla gina_, Is. Geoffr., Arch. Mus., viii., pls. 2-4 (1852).

_Troglodytes savagei_, Owen, P. Z. S., 1848, p. 29.

_Gorilla savagei_, Is. Geoffr., Rev. et. Mag. de Zool., p. 104 (1853);
Gray, Cat. Monkeys Brit. Mus., p. 7 (1870).

_Pithecus gorilla_, Blainv., Osteogr., pls. 2, et 5 bis (errore _P.
gesilla_).

PLATE XL.

{181} _Satyrus adrotes_, Meyer, Arch. f. Naturg., p. 182 (1856).

_Simia gorilla_, Schl., Mus. Pays-Bas, vii., p. 8 (1876).

_Gorilla mayema_, Alix et Bouv. C. R., lxxxv., p. 58 (1878).

(_Plate XL._)

CHARACTERS.--The face of this massive and most ponderous of all the Apes is naked and black, very wide and elongated. The large head has a ridge of hair along the central crest, and its lower jaw is very wide and far extended backward. The nose is long and high, and broad and flat at its extremity, and is also grooved longitudinally. The muzzle is broad, the mouth wide; the upper lip short, and the lower mobile and protrudable. The eyes are large; the ears naked and black, with the posterior upper angle pointed, and the lower margin produced into a rudimentary pendulous lobule.

The cranial region is comparatively small. The supra-orbital ridges, in which the eye-brows are set, form, from their prominence, a marked feature of the face. They overhang the eyes, causing them to appear very much sunk in the skull. The neck is short, the chest and shoulders wide, thickly haired and suggestive of great strength.

The arms are much longer than the fore-arms, and the feet, which have no in-step, exceed the hands in length, and are much broader than in other genera of the _Simiidæ_. The heel, which in the Orangs is small, is in the Gorilla strongly developed, on which account it can easily stand erect. Its opposable great-toe is large and flattened, and has a wide nail; while the lower joints of the second, third, and fourth toes--which are also short and thick--are united by a web. The arms, on which the hair converges on both sides of the joint towards the elbow, are so long as to reach down to the middle {182}of the leg when the Gorilla stands erect. The thumb is short and thick, and is tipped with a broad nail. The hand is broad, thickly haired on the back, and wrinkled from the wrist to the fingers. The fur of the Gorilla consists of long, thick, straight, or stiffly curved bristles, beneath which is a shorter curled woolly hair, or under-fur.

The skull of the adult male has very protruding jaws, and enormous supra-orbital ridges. The cheek-bones are broad; the temporal muscles meet along the top of the cranium, and have enormous bony crests for their attachment. The same is the case on the back of the head for the powerful neck-muscles. The true form of the skull is obscured by these great ridges and by the extent to which the face protrudes. The brain-case is better shaped internally than appears externally. The orbits have the same form as in Man.

The canine teeth are enormously developed. The upper molars are four-cusped, and have the oblique ridge, already often referred to, from the front inner to the hind outer cusp, the posterior of the three being much larger than the other two, a character distinguishing its jaw from that of Man and the Chimpanzees. The anterior lower molars have five cusps, three on the outer side and two on the inner, as in Man.

The lower jaw has no true chin, and its symphysis is very long and quite different from what is seen in the human symphysis. The opening for the passage of the spinal cord is situated in the posterior third of the base of the skull, and not, as in Man, nearly in the centre.

The vertebræ of the neck, back, and loins number the same--seventeen--as in Man; but there are thirteen parts of ribs instead of twelve. The neck-vertebræ have long spines which contribute to the thickness of the neck. The curvature, characteristic of {183}Man, in the lumbar region of the vertebral column of the young Gorilla, is more developed than in the Chimpanzee, and in both are earlier developed than in Man. (_Symington._)

The wrist (_carpus_) contains but eight bones, as there is no central (_os centrale_) bone, a character in which it agrees with Man and the Chimpanzee, but differs from the Orang.

The volume of the brain in the largest Gorilla rarely exceeds 34½ cubic inches, which is only half the capacity of the human skull. It may be safely said that an average European child, of four years old, has a brain twice as large as that of an adult Gorilla. The weight of a healthy human brain never falls below 31 ounces; that of the largest Gorilla has probably never reached 21. (_Huxley._)

In the brain of the Gorilla the cerebellum can be seen between the deep longitudinal fissure which separates the two halves of the cerebrum. It agrees in this with the Orang and _Anthropopithecus calvus_--the latter exhibiting even a greater divergence of the cerebral lobes.

The young male Gorilla differs much from the adult; its central cranial crest is less prominent than the occipital ridge for the neck muscles.

The female is much smaller than the male, but the cheeks are relatively broader; the cranial crests and ridges are less strongly marked, and the canines shorter and less powerful. Her breasts are long and pointed, not globular.

The height of the adult male Gorilla is over six feet, but the female rarely exceeds four feet six inches.

The general colour of the Gorilla is black or blackish; the whole skin of the face is glossy, set with a few hairs, and deep black; the crown reddish-brown, sometimes of a dark brown, the hairs being dun-coloured at the root, grey in the middle, {184}and dark brown at the tip; on the sides of the face the hair is dark brown or black, grey at the root; on the neck and shoulders the hair is grey at the root, and lighter towards the point. The back, the region of the humerus, and the thighs are brownish, the hair being pale grey at the root, blackish-brown further up, and dark grey at the termination; the fore-arms, the hands, ankles, and feet, dark brown or black; round the posterior is a circle of white hair in some, in others of brownish-yellow. Old individuals become grey or grizzled.

DISTRIBUTION.--Western Equatorial Africa, between the Cameroons and the Congo. This region presents a variety of hill and dale; the uplands are clothed with forest, and the dales are covered with grass and low bush, with abundance of fruit-yielding trees.

HABITS.--This extraordinary animal, round which have gathered so many myths, derived mostly from the inexact and magnified tales of the natives, still further exaggerated by careless or imaginative visitors to the West Coast of Africa, was first brought to the knowledge of science by Dr. Thomas Savage, an American Medical Missionary, in 1847. From that time downwards numerous preserved specimens of the animal have been received in excellent condition, so that its anatomy is very fully known. In 1860 the first living individual reached Europe, and lived for some months in Wombwell's Menagerie. Since that date both English and continental menageries have had specimens in captivity. What we know of the habits of the Gorilla is greatly based on observations made on these captive animals. Abundant statements to the contrary notwithstanding, very few persons, competent to give an intelligent account of their habits, have ever seen the Gorilla alive in its native state. {185}Even now, for our best accounts, we are indebted to Dr. Savage, who obtained most of his information from the natives, whose language and character he understood so thoroughly that he was able to extract from them, by carefully sifting their statements, most accurate information free from exaggeration and conjecture.

The Gorillas live in small companies, or rather families, consisting of their young of different ages, along with the father and mother. Like the Orang, the Gorilla is said to build a sort of platform-nest or shelter to pass the night in, of sticks or twigs laid crosswise on the branch of a strong tree, and within about twenty feet from the ground. The male sits, it is said, on guard below, the female and her family occupying the platform above. "My informants," says Savage, "all agree in the assertion that but one adult male is seen in a band." One gets the mastery by killing or driving out the other males.

Professor Hartmann writes: "The Gorillas roam [during the daytime only] through the tracts of the forest, which surround their temporary sleeping-places, in order to seek for food. In walking they place the back of their closed fingers on the ground, or, more rarely, support themselves on the flat palm, while the flat soles of their feet are also in contact with the ground. Their gait is shuffling; the motion of the body, which is never upright as in Man, but bent forward, is somewhat rolling, or from side to side. The arms being longer than those of the Chimpanzee, it does not stoop so much in walking; like that animal it makes progression by thrusting its arms forward, resting its hands on the ground, and then giving its body a half-jumping, half-swinging motion between them. In this act, it is said not to flex the fingers to rest on its knuckles, like the Chimpanzee, but to extend them, making a fulcrum {186}of the hand. When it assumes the walking posture, to which it is said to be much inclined, it balances its huge body by flexing its arms upward."

The Gorilla has the power of moving the scalp freely forward and backward--as Man in many instances has the power of doing--and, when enraged, of corrugating his brows and erecting the hair over the central bony crest "so as to present an indescribably ferocious aspect." He is capable of emitting a "terrific yell that resounds far and wide through the forest"; and when shot his cry is like that of a human being in sudden and acute distress. The Gorilla is very ferocious and never runs away, as the Chimpanzee does; he advances to attack his enemies, but according to some observers, however, only when molested, rushing forward in a stooping attitude, then rising to his feet to strike. He is also credited with fighting with his teeth, as well as his hands, biting his antagonist, as the Orangs and the Chimpanzees do. He exhibits great intelligence, though less, perhaps, than the Chimpanzee.

The females prove affectionate mothers, bravely protecting their young at the cost of their own lives. "In a recent case," writes Dr. Savage, "the mother, when discovered, remained upon the tree with her offspring, watching intently the movements of the hunter. As he took aim, she motioned with her hand, precisely in the manner of a human being, to have him desist and go away. When the wound has not proved instantly fatal, they have been known to stop the flow of blood by pressing with the hand upon the part, and when this did not succeed to apply leaves and grass."

The food of the Gorilla consists of all sorts of forest and cultivated produce; but the top of the fruiting stem of the oil-palm (_Elais guineensis_), the Papaia (_Carica_), and plantains {187}appear to be the fruits he most appreciates. Its dexterity in captivity in eating from utensils of civilised life is particularly remarkable, as Dr. Falkenstein records of a Gorilla he had alive for a considerable period. "He took up every cup or glass with instinctive care, clasped the vessel with both hands, and set it down again so softly and carefully that I cannot remember his breaking a single article.... He drank by suction, stooping over the vessel without even putting his hands into it or upsetting it, and in the case of smaller vessels he carried them to his mouth.... When he was anxious to obtain anything, no child could have expressed its wishes in a more urgent and caressing manner." When he was refused anything he had recourse to cunning, and looked anxiously to see if he was watched, and it was "impossible not to recognise a deliberate plan and careful calculation." When he had done what he had been forbidden or prevented from doing, "his whole behaviour made it clear that he was conscious of transgressing." The Gorilla is said by Dr. Savage to be very filthy in its habits, but Dr. Falkenstein's observations disagree with this statement. On this point the latter says "his cleanliness was remarkable."

The Gorilla generally adopts a squatting position, with its arms folded across its breast. When asleep he lies stretched out at full length on his back or side, with one arm under his head.

The Gorilla is very delicate, and rarely lives long in captivity, even in his own land.

THE CHIMPANZEES. GENUS ANTHROPOPITHECUS.

_Anthropopithecus_, De Blainville, Leçons Orales (1839).

_Troglodytes_ (nec V.), Geoffr., Ann. Mus., xix., p. 87 (1812).

{188}This genus contains those Apes which stand highest, next to Man, in the animal kingdom. This proximity, however, refers only to his external conformation and his anatomical structure.

The Chimpanzees approach very closely to the Gorilla in structure. Indeed the Gorilla was at first placed in the same genus as the Chimpanzee, which was much earlier known to science than its larger cousin, although an excellent description of the Gorilla, under the name of Pongo, was brought to this country by Andrew Battell, an English prisoner of the Portuguese in Angola, early in the seventeenth century, and published in "Purchas his Pilgrimage," in 1613, a story which for the first time referred definitely to the Chimpanzee.

The body is heavily built, but shorter and less robust than that of the Gorilla. The crown is depressed, and the supra-orbital ridges, from which rise stiff strong eye-brows, are prominent, but not remarkably so. The eye-lids are wrinkled, and their margins set with eye-lashes. The nose, of which the ridge is shorter than in the Gorilla, is depressed in the middle, flatter at the extremity, and, as in the last-named species, is furrowed longitudinally, its nostrils looking more downward and forwards. The lips are extremely mobile and protrusile, the upper one broad and the lower one retreating from the mouth, and not forming a true human-like chin, though it is more prominent than in the Orang. The cheeks are more wrinkled than in that Ape. The ears are large and projecting from the side of the head, and often carry a lobule. They are strangely like those of Man, and, as Mr. Darwin has remarked, the Chimpanzee never moves or erects its ears, so that they are equally rudimentary, as far as that function is concerned, as in Man. The shoulders and chest are broad, and indicate great strength. Their lower limbs are longer in proportion than in the Orang. {189}The foot, which is anatomically in no respect a hand, is sometimes shorter than the latter, the great-toe is thick, opposable, and thumb-like, the other four toes are united together by a web, the heel is somewhat developed, and the whole of the sole of the foot is applied to the ground when walking. The arms, of which the humeral segment is about equal in length to the fore-arm, are long, but reach only a little below the knee--their span being about a half more than the height of the body. The hands, which are wonderfully human in form, are broad, comparatively short, and less hook-like than in the Orang. The hair on the arm and fore-arm converges towards the elbow, as in the Gorilla and Orang. The thumb is short in comparison with the same digit in Man, and, as in the human hand, the middle finger is the longest; the outer four fingers being united by a web reaching up to the first joint. The palm of the hand can be applied flat to the ground; but though the Chimpanzees can stand or run erect on the flat sole of the foot, they prefer to advance leaning forward, supporting themselves on the knuckles of the hand. They have no callosities on the ischiatic bones, on which they sit.

The female Chimpanzees are slightly smaller than the males, but the disparity between them is much less than between the two sexes of the Gorilla. The nose and teeth are less prominent, and the belly is more tun-shaped. The young males also exhibit fewer differences from the adult than among the Gorillas, though differing in many points of their soft anatomy and osteology. The nose lengthens, and its extremity widens, while the face becomes more prognathous with increasing years. In the young the frontal bone is low and flat. The skull in the Chimpanzee is elongated, and small in proportion to the body; the forehead is smaller, the crown more rounded than {190}in the Gorilla, and the back of the head convex.[2] The central (sagittal) crest, so strongly developed in the Gorilla and the Orang, is here wanting; the supra-orbital ridges which extend across the face, and the occipital prominences for the back-muscles, though large, are also less marked. The orbits have a circular rim, and are less prominent than in the Gibbons. The nasal bones are but slightly arched, and the openings for the nostrils round and small. The jaws, which are smaller, proportionately to the cranium, in this genus, than in any other of the _Simiidæ_, protrude far forward, but the symphysis of the lower jaw is smaller than in the Gorilla, and its two halves low and wide. The bones of the skull are much hollowed out into cavities (sinuses) in the forehead, nose, and jaws, all of which communicate with each other. The plane of the _foramen magnum_ (for the passage of the spinal cord) is oblique to the plane of the base of the skull.

The volume of the cranium is from twenty-six to twenty-seven cubic inches, or about one-half of the lowest capacity of a normal human cranium. A styloid process is more or less distinctly visible in the Chimpanzees.

The canine teeth are long and conical, but less than in the Gorilla; and the diastema, or gap, between them and their neighbouring teeth is smaller than in the other Apes. The molar teeth are four-cusped, and have the oblique ridge already described extending from the front inner to the hind outer cusp; and the middle lower molar has five cusps, both these dental characters being similar to those in Man. The anterior lower pre-molar, however, is pointed, and has a long sharp anterior edge, as in the _Cercopithecidæ_.

{191}The vertebral column begins to show the S-shaped flexure, characteristic of Man's back-bone; it presents also a human character in the form of its second neck vertebræ, and there are thirteen pairs of ribs, as in Man. The hindmost vertebræ "give the impression of a rudimentary tail." (_Hartmann._)

The humerus is nearly equal in length to the fore-arm; the wrist (_carpus_) has only eight bones (the central bone being absent), agreeing, therefore, with the number in Man.

All the ridges and grooves seen in the human brain are present in that of the Chimpanzee, but "they are simpler and more symmetrical, and larger in proportion to the brain." (_Huxley._) The cerebellum, and the nerves also, are larger in proportion to the cerebrum than in Man; and certain structures (the _corpora trapezoidea_) which exist in the brains in the lower Mammalia are absent. These prominences, which are situated in that portion of the brain known as the _medulla oblongata_, at the summit of the spinal cord, disappear, as we have seen, in all the genera of higher rank than the _Cebidæ_, one of the lowest families of the _Anthropoidea_. The brain in its convolutions and in many other respects conforms to that of the Orang. This is especially the case in _A. calvus_.

The uvula, which is absent in the throat of the Orang, is pendulous in the Chimpanzees, as in Man. Large air-sacs are also present, and the hyoid bone is excavated posteriorly, suggesting the conformation of the same bone in _Alouatta_ (the South American Howlers). The stomach is very similar to that of Man, and so are the digestive and reproductive organs. The round ligament, attaching the head of the thigh-bone into its pelvic socket, is present, and restricts the flexibility of the hind-limb of the Chimpanzees, compared with that of {192}the Orang. Its presence, however, while acting somewhat less favourably in regard to the climbing capacities of these animals, whose habits are less essentially arboreal than the Orangs', beneficially assists them in walking, affording them a firmer support on the ground. In the Chimpanzee there is always a semi-lunar fold (_plica semilunaris_) in the inner corner of the eye, corresponding to the nictitating membrane (or third eyelid) of birds. In some of the Lemuroids it is well developed (_suprà_, vol. i., p. 90), and is large in some races of men.

The Chimpanzee is confined to the West African Sub-region, as defined by Dr. Bowdler Sharpe. It is known from Loango, along the banks of the Upper Congo, and Mr. Monteiro (P. Z. S., 1871, p. 544) says it is quite unknown to the south of the Congo; it also occurs throughout the country of the Manyema, in Central Africa, where Livingstone describes it under the name of Soko; and southward as far as 10° south latitude, to Lake Moero. Schweinfurth has recorded it from the Niam-niam country.

The Chimpanzees inhabit forest regions, and feed on wild fruits in the woods, and the products of cultivated gardens, not rejecting, when they can capture it, animal food. They live in separate families, or in limited communities of small families mixed together, but each male lives with his own single female. They are more arboreal than the Gorilla, but much less so than the Orangs. In many districts they seem to live on the ground.

They emit loud cries, shrieks, and howls in the morning and evening, and often during the night. "Since they are really accomplished in the art of bringing forth these unpleasant sounds, which may be heard at a great distance, and are reproduced by the echoes, it is impossible to estimate the number {193}of those who take part in the dreary noise, but often we seemed to hear more than a hundred." (_Pechuel-Lösche._) These Apes also build resting-places, not far from the ground, like the Orangs, composed of twigs and sticks on the branch of a tree or a crotch, in which the female and her young take refuge for the night, the male placing himself on guard beneath.

They seldom make an unprovoked attack on the natives wandering in the forest; on the contrary, they are peaceably disposed animals, glad to get out of the way of danger or possible enemies. Yet, when pressed, they form no mean antagonist. Biting is their principal mode of defence.

"As seen here," says Savage, "they cannot be called gregarious, seldom more than five or ten at most being found together. It has been said on good authority, that they occasionally assemble in large numbers in gambols. My informant asserts that he saw once not less than fifty so engaged, hooting, screaming, and drumming with sticks upon old logs, which is done in the latter case with equal facility by the four extremities.... When at rest, the sitting posture is that generally assumed. They are sometimes seen standing or walking, but when thus detected, they immediately take to all fours, and flee from the presence of the observer. Such is their organisation that they cannot stand erect, but lean forward. Hence they are seen, when standing, with the hands clasped over the occiput, or the lumbar region, which would seem necessary for balance or ease of posture."

Most of the accounts of the habits we have of Chimpanzees, refer to those of young individuals kept in captivity. There is still much to be discovered as to the ways and modes of life of the adults of both the Chimpanzee and the Gorilla. They are both very delicate, and in temperate climates rarely live {194}more than a few months; a Bald Chimpanzee (_A. calvus_), however, survived five years in the Zoological Gardens, in London.