Handbook to the Primates/Simiidae

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[ 143 ]

THE MAN-LIKE APES. FAMILY SIMIIDÆ.

In this family are included the Gibbons, the Orangs, the Gorillas, and the Chimpanzees, the most highly organised and the nearest to Man in structure of all the Anthropoidea. To [ 144 ]these groups the term "Ape," has been by many writers chiefly restricted, the remaining families of the Old World, and all of the Western Hemisphere, being designated "Monkeys" as a convenient method of nomenclature. The outward resemblance of the Simiidæ to Man has made the various members of the family objects of the greatest interest, not alone to the naturalist, but to every intelligent person; and has naturally suggested a constant inter-comparison between the characters of both.

They are all essentially arboreal climbing animals, yet when they come to the ground they progress in a semi-erect position of their own accord. Their front-limbs are always so much longer than their hind-limbs, that when walking on a level surface their fingers reach the ground, without stooping lower than their semi-erect attitude. Their front-limbs vary in length in the different genera; so does the thumb; but their great-toe is always smaller in proportion to the foot than it is in Man, and, unlike his, is opposable to the other toes. As they belong to the Catarrhine group, their nose has a narrow partition between the nostrils, which are directed downwards. In all, an external tail, cheek-pouches, and (except among the Gibbons) ischial callosities are wanting. All are covered with hair, some more thickly than others, but no Ape has on its head the long abundant locks which Man possesses.

The form of the skull varies very greatly in the Simiidæ. It is, however, always longer than broad. In its frontal region it is never so rounded and elevated as in Man. The roof of the eye-sockets projects into the fore part of the brain-cavity, and considerably reduces its capacity. The pre-maxillary bones (carrying the incisor teeth) are relatively more distinct and much larger than in Man, "the sutures [ 145 ]separating them from the maxillary bones remaining visible after the adult dentition has been obtained." (Mivart.)[1] The Simiidæ have a bony meatus or canal to the ear. The back part of the head, which among the Guenons is flat, is convex among the Simiidæ. The palate is long and narrow, and the margins of the jaws nearly parallel. The lower jaw is always in one piece, the two halves being firmly ossified in the middle. The dental formula of the Man-like Apes is I 2/2, C 1/1, P 2/2, M 3/3 (i.e., 32 teeth in all); their inner upper incisors are larger, and the lower are smaller than the outer pair; the canines are large, and between them and the neighbouring incisor above there is a vacuity (or diastema), and, below, between them and the nearest pre-molar. The upper pre-molars have three roots, and the lower, two; the upper molars have four tubercles, their crowns being relatively wide; the lower molars have five tubercles, but the posterior has no hind talon.

The opening for the passage of the spinal cord is situated towards the posterior portion of the base of the cranium, and is thus further from the centre than in Man.

Except among the Gibbons, the vertebral column shows in the sacral region indications of that curve—or concavity in the back between the two convexities of the neck and loins—which is one of the distinctive characters of the human skeleton. The processes for the interlocking of the vertebræ, which are large in the lower Anthropoids, are much reduced in the Man-like Apes, and become inconspicuous in Man.

The breast-bone is flat, and resembles that of Man, and, in all, except the Orang, is composed of two bones. The [ 146 ]arm-bone is often shorter than the fore-arm. The radius and ulna can be completely rotated. The articulating surface of the trapezium, the wrist-bone (carpus), to which the thumb is attached, has a rounded face like that of the ento-cuneiform bone in the ankle (tarsus), a form which, as already pointed out (Vol. I., p. 11), was in the Lemuroids correlated with an opposable great-toe, so here it is correlated with a true opposable thumb. In the Monkeys and Lemuroids this bone is not generally rounded, and they have not the thumb opposable in the strict sense that it is among the higher Apes.

The thigh-bone (femur) is shorter than the arm-bone (humerus); and the foot is very long; yet the absolute length of the tarsus is never so great as in Man; it is the rest of the foot which is so much longer relatively in Apes. The ento-cuneiform, or articulating bone of the ankle for the great-toe, has a sub-cylindrical surface, which gives a great range of motion to that digit, towards and from the plane of the foot.

The brain of the Apes closely resembles in general form and structure that of Man; but the cerebral hemispheres differ in being much elongated and depressed, and the cranial capacity of the skull, which is never less than 55 cubic inches in any normal human subject, is in the Chimpanzee 27½ cubic inches; in the Gorilla 35 inches; in the Orang 26 inches; and in the Gibbons very much less. The cerebrum has its surface richly convoluted; and its posterior lobes always entirely over-arching the cerebellum, except in the Siamang (Hylobates syndactylus).

"As to the convolutions, the brains of the Apes exhibit every stage of progress, from the almost smooth brain of the Marmoset, to the Orang and the Chimpanzee, which fall but little below Man. And it is most remarkable that as soon as [ 147 ]all the principal sulci [or grooves] appear, the pattern according to which they are arranged is identical with that of the corresponding sulci of Man. The surface of the brain of a Monkey exhibits a sort of skeleton map of Man's, and in the Man-like Apes the details become more and more filled in, until it is only in minor characters, such as the greater excavation of the anterior lobes, the constant presence of fissures usually absent in Man, and the different disposition and proportions of some convolutions, that the Chimpanzee's or the Orang's brain can be structurally distinguished from Man's.... And the difference between the brains of the Chimpanzee and of Man is almost insignificant when compared with that between the Chimpanzee's brain and that of a Lemur." (Huxley.)

The Anthropoid Apes have no cheek-pouches. The larynx has large dilatations of the shallow depressions—called ventricles—of the mucous membrane on each side of its inner surface—which may extend down as far as the arm-pits, and be connected with powerful voice possessed in most of the species. The stomach is simple, like that of Man, and not sacculated, as in the last family (the Cercopithecidæ).

The uterus and other structures connected with the reproductive system resemble those in the human subject. The length of gestation varies probably in the different genera, and is unknown in many of the species. The period for which the young are suckled by the mother lasts about six months. "The proportions of the limbs to one another and to the body do not sensibly change after birth; but the body, limbs, and jaws enlarge to a much greater extent than the brain-case." (Huxley.) Observations are still required, in regard to most of the species, as to the age at which they arrive at maturity, and are able to reproduce.

[ 148 ]The Simiidæ—the most intelligent of the animal kingdom—are all diurnal animals, and essentially arboreal. Many of the members of the family have, when walking, a tendency to tread on the outer edge of the foot, turning, therefore, the toe inward on account of the free motion which is possible between the various bones of its ankle, whereas, in the human foot, these bones are more solidly bound together. When climbing, the power of turning in the sole is, as is evident, of the greatest advantage to the Ape. Their food is chiefly vegetable; a few species exhibit slight carnivorous tendencies.

"Of the various genera of the Simiidæ, the Gibbons are most remote from Man. The Orangs come nearest in the number of the ribs, the form of the cerebral hemispheres, and certain other characters of the brain and skull; but they differ from him much more widely in other characters, especially in the limbs, than the Gorilla and the Chimpanzee do. Of the Chimpanzees the Gorilla is more Man-like in the proportions of the leg to the body, and of the foot to the hand; and likewise in the size of the heel, the curvature of the spine, and the absolute capacity of the cranium. The true Chimpanzees approach Man most closely in the skull, dentition, and proportionate length of the arms." (Huxley.)

The Simiidæ are confined to the Ethiopian and Indian Regions. The Gorillas and Chimpanzees live exclusively in the Tropical Regions of Western and Central Africa; the Gibbons range into all the four provinces of the Indian Region; while the Orangs are confined to two islands of the Indo-Malayan Sub-region.


THE GIBBONS. GENUS HYLOBATES.

Hylobates, Illiger, Prodr. Syst. Mamm., p. 67 (1811).

The group of Tree-walkers, as the term Hylobates signifies, [ 149 ]embraces the smallest-sized, the slenderest-bodied, the longest-limbed, and the most perfectly arboreal of all the Man-like Apes. All are covered with thick woolly hair, which, on the arms and fore-arms, converges (except in H. agilis) towards the elbow.

Their head is small and round, and the face compressed. Except the Orangs, the Gibbons have the longest arms of all the Apes, so long that when they stand erect the points of their fingers can touch the ground. Compared with the spinal column, their arms are as 19 to 11, while the legs are one-third longer than it. The fore-arm is much longer than the arm itself; the hand is longer than the foot, and the thumb is very long in proportion to the hand. The knee is free from the side of the body, and the great-toe is well developed and nearly one-half the length of the foot. The nails of both the thumb and the great-toe are flat. Callosities, which are wanting in all the other genera, are present in Hylobates, but are very small.

In the skull the occiput is convex; the orbits are very large and deep, and the supra-orbital ridges prominent. The canine teeth are much larger than the others, and equally large in both sexes. They are generally the last of the permanent teeth to come in, but in the Gibbons they generally precede, or are developed along with, the last molar.

The vertebral column is nearly straight, presenting but little of the spinal curvature seen in Man; it has also in the dorso-lumbar region one vertebra more than in the human skeleton. The articulating head of the arm-bone (humerus) loses the direction it had among the Monkeys, and looks upward and forward as in Man. The wrist (carpus) has nine bones, as in the lower Anthropoidea. The skeleton of the hand is more [ 150 ]than half the length of the spine, and the foot is slightly under half its length. The Gibbons have two pairs of ribs more than Man. The ends of the ischial bones are much everted to support the callosities.

With regard to the brain, this genus is remarkable for the great reduction of the occipital lobes of the cerebrum.

The tongue is very similar to that in Man, but it is furnished with a sub-lingual process like that already described among some of the Lemuroids. The Gibbons (except the Siamang) have no laryngeal sacs. The stomach closely resembles the human organ.

The Gibbons are very delicate, and rarely live long in confinement, even in their own country. They are in general highly intelligent, very gentle, and become most affectionate and engaging animals if kindly treated. They are, however, occasionally irascible and ill-tempered, especially when adult.

Their feats of climbing and leaping are almost proverbial. It would be impossible to excel them as acrobats. When walking on the ground they assume the erect posture, putting the soles of their feet to the ground, separating the thumb and the great-toe widely from the neighbouring digits.

"They walk erect, with a waddling or unsteady gait, but at a quick pace; the equilibrium of the body requiring to be kept up, either by touching the ground with the knuckles, first on one side then on the other, or by uplifting the arm so as to poise it. As with the Chimpanzee, the whole of the narrow, long sole of the foot is placed upon the ground at once and raised at once, without any elasticity of step." (Martin.)

Their voice is very powerful and can be heard at a great distance, especially when they are howling in chorus. The [ 151 ]Wau-Wau and the Siamang, the one without, and the other with, a laryngeal sac, are equally vigorous in this respect.

The female produces but a single young one at a birth, of which she takes the greatest care. She carries it about, clinging to the under side of her body, for many months. It is said that she even takes it to the waterside from time to time, and with much solicitude, and in spite of its cries and resistance, washes its face.

The Gibbons frequent the great upland forests; but the Siamang (H. syndactylus) may be met with at quite low levels and close to the coast. Their food consists of fruit, leaves, and insects, eggs of birds, and apparently birds and lizards, and especially spiders. They drink either by putting the mouth down to the water, or by dipping in their hands and thus carrying it to their mouths.

The Gibbons are confined to two Sub regions of the Indian Region. With the exception of the Siamang, all the so-called species of Hylobates are so closely allied to each other, and differ by characters of such slight importance, that they seem to be hardly worthy of specific distinction. (Thomas.)


I. THE AGILE GIBBON. HYLOBATES AGILIS.

Pithecus lar (nec L.), Geoffr., Ann. Mus., xix., p. 88 (1812).

Hylobates agilis, F. Cuv., Hist. Nat. des Mammif., Sept. 1821, pls. v., vi.; Müller, Tijdschr. Nat. Gesch., ii., p. 326 (1835); Martin, Mammif. Anim., p. 416 (1841); Fry, P. Z. S., 1846, p. 11; Gray, Cat. Monkeys Brit. Mus., p. 12 (1870); Schl., Mus. Pays-Bas, vii., p. 17 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 9 (1878; with full synonymy).

Pithecus agilis, Desmar., Mamm., p. 532 (1820).

[ 152 ]Simia lar (nec L.), Raffl., Tr. Linn. Soc., xiii., p. 242 (1822).

Hylobates lar (nec L.), F. Cuv., Hist. Nat., Mamm., pls. 7, 8 (1824); Blyth, J. A. S. Beng., xliv., ex. no., p. 2 (1875).

Hylobates variegatus, Temm., Monogr. Mamm., i., p. xiii. (1827); Wagner in Schreb. Säugeth. Suppl. v., p 16 (1855); H. O. Forbes, Nat. Wand. East. Arch., p. 156 (1885).

Hylobates rafflesii, Is. Geoffr., Cat. Méth. Primates, p. 8 (1851); Gray, Cat. Monkeys Brit. Mus., p. 11 (1870).

Hylobates pileatus, Gray, P. Z. S., 1861, p. 136, pl. xxi.; id., Cat. Monkeys Brit. Mus., p. 10 (1871); Anderson, Zool. Res. Exped. Yun-nan, p. 6 (1878).

Characters.—Face black; colour entirely black, but becoming brown on the back and sides, and with a white superciliary band, and sometimes ashy-grey cheeks.

This is the typical form of the species in Mid-Sumatra, where the present writer had the opportunity of examining it alive. It was with difficulty distinguished from H. syndactylus, except from its size and the presence of the white superciliary band.

Other specimens (but none of them met with to the south of the Moesi river by the present writer) have been described, with the occiput, the back from immediately behind the shoulders, the flanks, the hips, and the outer surfaces of the fore- and hind-limbs, pale yellow. The shoulders, chest, and belly, and the inside of the limbs and feet dark brown; eyebrows and whiskers pale grey. (Anderson.)

The variety described as H. pileatus is distinguished by a black cap-like patch on the top of the head; the chest, throat, and belly black; the back of the head, the upper surface of the body, the limbs and area round the black cap grey. This variety may also be entirely white, except for the coronal cap [ 153 ]and chest being black, and the back brown; or the pervading colour may be brown, the sides of the face and the under surface black, and the whiskers white. The index and middle fingers are occasionally webbed together.

All the hairs on the arm and fore-arm converge towards the wrist.

Distribution.—This species is confined to Sumatra and to Siam. In the former country it is known by the name of "Ongka" by the Malays, who, with the keen powers of observation they possess in regard to all natural objects, recognise two varieties, the white or yellow variety—"Ongka putih," and the black one—"Ongka itam" (H. rafflesi). The capped variety (H. pileatus) with its variously coloured forms inhabits Siam.

Habits.—The habits of the "Ongka" are very similar to those of the Wau-wau, or the Siamang (H. syndactylus). The natives, however, aver that it is much more silent, rarely howling as either of these other two species do. They are also seen generally in quite small troops, and often in pairs only.

"It is almost impossible," writes Mr. Martin of a specimen that lived formerly in the Zoological Gardens, "to convey in words an idea of the quickness and graceful address of her movements: they may, indeed, be termed aërial, as she seems merely to touch, in her progress, the branches among which she exhibits her evolutions. In these feats her hands and arms are the sole organs of locomotion; her body hanging as if suspended by a rope, sustained by one hand (the right, for example), she launches herself by an energetic movement to a distant branch, which she catches with the left hand. But her hold is less than momentary; the impulse for the next [ 154 ]launch is acquired; the branch then aimed at is attained by the right hand again, and quitted instantaneously, and so on, in alternate succession. In this manner spaces of twelve and eighteen feet are cleared with the greatest ease, and uninterruptedly for hours together, without the slightest appearance of fatigue being manifested; and it is evident that if more space could be allowed, distances very greatly exceeding eighteen feet would be as easily cleared.... Sometimes on seizing a branch in her progress, she will throw herself, by one arm only, completely round it, making a revolution with such rapidity as almost to deceive the eye, and continue her progress with undiminished velocity. It is singular to observe how suddenly this Gibbon can stop, when the impetus given by the rapidity and distance of her swinging leaps would seem to require a gradual abatement of her movements. In the very midst of her flight a branch is seized, the body raised, and she is seen, as if by magic, quietly seated on it, grasping it with her feet.... A live bird was let loose in her apartment; she marked its flight, made a long swing to a distant branch, caught the bird with one hand in her passage, and attained the branch with her other hand; her aim, both at the bird and the branch, being as successful as if one object only had engaged her attention. It may be added, that she instantly bit off the head of the bird, picked its feathers, and then threw it down, without attempting to eat it."


II. THE WAU-WAU GIBBON. HYLOBATES LEUCISCUS.


A. Javan Race (H. leuciscus).

Simia leucisca, Schreber, Säugeth. i., pl. iii. b. (1775).

Pithecus leuciscus, Geoffr., Ann. Mus., xix., p. 89 (1812).

[ 155 ]Hylobates leuciscus, Kuhl, Beitr. Zool., p. 6 (1820); Desmar. Mamm., p. 51 (1820); Martin, Mammif. An., p. 416 (1841); Is. Geoffr., Cat. Méth. Primates, p. 7 (1851); Wagner, Schreb., Säugeth. Suppl. v., p. 16 (1855); Gray, Cat. Monkeys Brit. Mus., p. 15 (1870); H. O. Forbes, Nat. Wand. East. Arch., p. 70 (1875); Schl., Mus. Pays-Bas, vii., p. 19 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 7 (1878; with full synonymy).

B. Bornean Race (H. concolor).

Simia concolor, Harlan, Journ. Acad. Nat. Sc. Phil., v., p. 229 pl. ii. (1827).

Hylobates harlani, Less., Bull. des Sc. Nat., xiii., p. 111 (1827).

Hylobates concolor, Schl., Essai Phys. Serp., p. 237 (1837); S. Müller, Verhand. Gesch., p. 48 (1841); Blyth, J. A. S. Beng., x., p. 838 (1841); Martin, Mammif. An., p. 417 (1841); Fry, P. Z. S., 1846, p. 15; Wagner in Schreb. Säugeth. Suppl. v., p. 17 (1855; in part); Schleg., Mus. Pays-Bas, vii., p. 20 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 11 (1878).

Hylobates mülleri, Martin, Mammif. Anim., p. 444 (1841); Is. Geoffr., Cat. Méth. Primates, p. 7 (1851); Schlegel, Mus. Pays-Bas, vii., p. 21 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 8 (1878; with full synonymy); Hose, Mammals of Borneo, p. 6 (1893).

Hylobates funereus, Is. Geoffr., C. R., xxxi., p. 874 (Dec., 1850); Wagner in Schreb. Säugeth. Suppl. v., p. 18 (1855).

? Hylobates fuscus, Winslow Lewis, Bost. Journ. N. Hist., i., pt. i., p. 32, pls. i., ii. (1834).

Characters.—Fur thick, long and woolly. General colour ashy-grey, paler on the lower back and rump; hair round [ 156 ]the face grey; superciliary streak white; top of the head black; fingers and toes black.

This species has been found to possess occasionally a supernumerary finger on each hand.

Distribution.—The Indo-Malayan Sub-region. Java, Borneo, and the Sulu Archipelago between Borneo and the Philippines.

Habits.—The Wau-Wau—the Malay name for this Gibbon—is one of the first of the Quadrumana that makes its presence known to the traveller in Java, when he reaches its upland forest regions. In the evening, just about sundown, and more especially in the early morning commencing before sunrise and finally ceasing when the sun is above the tops of the trees, he will be surprised by a sudden outbreak of what appears to be now the loud plaintive wailings of a crowd of women, now the united howling of a band of castigated children. The present writer's first acquaintance with this charming genus of Monkeys was made among the Kosala hills in Western Java, and it will ever remain with him as one of many most pleasant recollections of a long tropical sojourn. Their "woo-oo-ut—woo-ut—woo-oo-ut—wut-wut-wut—wŭt-wŭt-wŭt," always more dolorous on a dull heavy morning previous to rain, is just such a cry as one might expect from the sorrowful countenance so characteristic of the species of Hylobates. The Wau-Wau has a wonderfully human look in its eyes; and it was with great distress that the writer witnessed the death of the only one he ever shot. Falling on its back with a thud on the ground, it raised itself on its elbows, passed its long taper fingers over the wound, gave a woeful look at them and at his slayer, then fell back at full length—dead—"saperti orang" (just like a man), as his Malay companion remarked. He kept in captivity for a short time a specimen which was brought to him by a native, and it [ 157 ]became one of the most gentle and engaging creatures possible; but when the calling of its free mates reached its prison house, it used most pathetically to place its ear close to the bars of its cage and listen with such intense and eager wistfulness that it was impossible to retain it in durance any longer. It was accordingly set free on the margin of its old forest home. Strange to say, its former companions, perceiving perhaps the odour of captivity about it, seemed to distrust its respectability, and refused to allow it to mingle with them. Amid the free woods we may hope that this taint was soon lost and that it recovered all its pristine happiness.

In general habits it in no way differs from the other species of Hylobates already described.

In regard to the Bornean specimens of this species, Dr. Anderson makes the following observations: "This species varies from grey to dark yellowish-brown, but the grey tint in certain lights appears pure ashy, and in others of a brownish tint. In some the chest and abdomen are frequently yellow, and this seems to be the character of individuals met with on the west coast of Borneo, while those inhabiting the meridional parts of the island have the hands and fore part of the body of a black-brown or reddish-brown. In both of these varieties there is a yellowish-white superciliary streak. The last of them leads into the varieties of Hylobates from the neighbouring islands of Sulu, to the north-east of Borneo, in which the upper parts of the body are either grey or brownish, the lower part of the back and the loins being a little more clear than the rest." The outer surface of the limbs, the back part of the head, the supercilium, and the sides of the face are more or less pure ashy-grey. "Specimens of this Gibbon obtained by me," writes Mr. Charles Hose, who is well known for his Bornean researches, [ 158 ]"at Claudetown, and now in the British Museum, show that the colouring in different parts of the body must be considered of little importance, as I obtained eleven specimens, five of which were in the same troop and the other six from the same locality, varying in colour as much as it is possible for them to do; some had yellowish backs and black chests, others black backs with yellowish chests, and some were nearly black all over; whilst others were almost a complete silver-grey. I, therefore, come to the conclusion that H. muelleri and H. leuciscus cannot be separated. The peculiar bubbling noise they make is similar. I think it very unlikely that two distinct species should be so constantly found together as they are in Sarawak.

"The natives call the silver-grey variety 'Emplian' or 'Wa-Wa,' and the dark one, 'Emplian arang' (coal), because of its colour."


III. THE WHITE-CHEEKED GIBBON. HYLOBATES LEUCOGENYS.

Hylobates leucogenys, Ogilby, P. Z. S., 1840, p. 20; Blyth, J. A. S. Beng., x., p. 838 (1841); Martin, Mammif. Anim., p. 445, cum fig. (1841); Is. Geoffr., C. R., xv., p. 717 (1842); id., Arch. Mus., ii., p. 535 (1843); Gray, Cat. Monkeys Brit. Mus., p. 11 (1870); Schl., Mus. Pays-Bas, vii., p. 13 (1876); Scl., P. Z. S., 1877, p. 679, pl. lxx.; Anderson, Zool. Res. Exped. Yun-nan, p. 6 (1878; with synonymy).

Characters.—Fur glossy, thick, and woolly; the hair of the upper and back part of the head standing vertically erect; the face, chin, and ears black; round the face from the level of the eyes and meeting below the chin runs a white border, forming [ 159 ]whiskers and beard; elsewhere the colour is entirely black. Length of the body, 26 inches.

Distribution.—Siam.

Habits.—This rare species is very active and gentle in confinement. It will hang suspended, as Martin observed in the first specimen brought to Europe, from a branch for the whole day, except when asleep or reposing.

The type specimen was described in 1840,—its skin being preserved in the British Museum; but it was not till 1877—after a lapse of thirty-seven years—that a second specimen was brought to this country. It was sent to the Zoological Gardens by Mr. W. H. Newman, H.B.M. Consul at Bankok.


IV. THE WHITE-HANDED GIBBON. HYLOBATES LAR.

Homo lar, Linn., Mantiss. Plant., App., p. 521 (1771).

Simia longimana, Wagner in Schreb. Säugeth. i., p. 66, pl. iii., figs. 1, 2 (1775); Erxl., Syst. Reg. An., p. 9 (1777).

Simia lar, Bodd., Elench. An., p. 55 (1785); Fischer, Syn. Mamm., p. 12 (1829; in part).

Pithecus lar, Latr., Hist. Nat. Buff., xxxvi., p. 276 (1809).

Pithecus varius, Latr., op. et loc. cit.

Pithecus variegatus, Geoffr., Ann. Mus., xix., p. 88 (1812).

Hylobates lar, Illig., Abhandl. Akad. Berl., p. 88 (1815); Martin, Mammif. Anim., pp. 416, 433 (1841); Blyth, J. A. S. Beng., x., p. 838 (1841); Gray, Cat. Monkeys Brit. Mus., p. 10 (1870); Scl., P. Z. S., 1870, p. 86, pl. v.; Schlegel, Mus. Pays-Bas, vii., p. 15 (1876); Anders., Zool. Res. Exped. Yun-nan, p. 5 (1878; with full synonymy); Blanford, Faun. Brit. Ind., Mamm., p. 7 (1891).

[ 160 ]Hylobates variegatus, Kuhl, Beitr. Zool., p. 5 (1820; young); Desmar., Mamm., p. 51 (1820); Is. Geoffr., Zool. Bélang. Voy., p. 27 (1834).

Simia albimana, Vig. et Horsf., Zool. Journ., iv., p. 107 (1828).

Simia variegatus, Fischer, Syn. Mamm., p. 11 (1829).

Hylobates albimanus, Is. Geoffr., Zool. Bélang. Voy., p. 29 (1834).

Hylobates entelloides, Is. Geoffr., C. R., xv., p. 717 (1842).

Hylobates leuciscus, Cantor, Ann. and Mag. N. H., xvii., p. 338 (1846).

Characters.Male.—Everywhere deep black, except the face, which is reddish-brown, with the thick hair round it light grey or white, and the hands and feet, which are pale yellow or white; superciliary ridges, whiskers and beard, white. The hair on the fore-arm is nearly erect, with only a very slight forward inclination. The species is subject to great variation, and may be of all shades, from deep black to entirely whitish-yellow (H. entelloides).

Head round; the eyes large; the cheeks flat and depressed; the nose slightly projecting, its tip furrowed, and its nostrils small and converging; the upper lip is divided in the centre by a vertical furrow. In very young individuals the top of the ear is markedly pointed.

Skull with the orbital ridges larger, the muzzle shorter, and the teeth smaller than in H. hoolock; the second and third toes sometimes united by a membrane.

Female.—Generally similar to the male, but more frequently entirely pale yellow, with the hands and feet paler.

Distribution.—Aracan, Lower Pegu, Tenasserim, and the Malay Peninsula.

Habits.—The White-handed Gibbon inhabits the upland [ 161 ]forests as high as 3,500 feet above the sea; living in troops numbering from ten to twenty-five. Its habits are very similar to those of other Gibbons, although Tickell observed that they were less light and active than the Hoolock, and had a different voice. It is said to drink, as the Siamang does, by dipping its hands into the water, and not to put its mouth down to it like the Hoolock. "So entirely does it depend on its hands for locomotion amongst trees," remarks Dr. Blanford, "that it carries everything in its feet. Tickell, from whom I take these details, says that he has seen a party of H. lar escape thus with their plunder from a Karen garden in the forest." "The young are born in the early part of the cold season," continues Dr. Blanford, "and each sticks to the body of its mother for about seven months, after which it begins gradually to shift for itself."


V. THE HOOLOCK. HYLOBATES HOOLOCK.

Simia lar, Phil. Trans., lix., p. 607 (1769.)

Simia hoolock, Harlan, Tr. Am. Phil. Soc., iv. (n. s.), p. 52, pl. 2 (1834.)

Hylobates coromandus, Ogilby, P. Z. S., 1837, p. 689; Martin, Mammif. Anim., p. 415 (1841); Is. Geoffr., Arch. Mus., ii. P. 535 (1843); Blyth, J. As. Soc. Beng., xiii., p. 464 (1844.)

Hylobates hoolock, Waterh., Cat. Mamm. Mus. Zool. Soc., p. 3 (1838); Martin, Mammif. Anim., p. 416 (1841); Is. Geoffr., Arch. Mus., ii., p. 535 (1843); id., Cat. Méth. Primates, p. 9 (1851); Sclater, P. Z. S., 1860, p. 86, pl. v.; Gray, Cat. Monkeys Brit. Mus., p. 11 (1870); Schl., Mus. Pays-Bas, vii., p. 14 (1876); Anderson, Zool. Res. Exped. Yun-nan, p. 1 (1878; with full synonymy); Blanford, Faun. Brit. Ind., Mamm., p. 5 (1891).

[ 162 ]Hylobates hulok, Wagner, in Schreb., Säugeth. Suppl., v., p. 20 (1855.)

Hylobates niger, Harlan; Ogilby, P. Z. S., 1840, p. 21.

Characters.—Black all over, except a frontal band, continuous or interrupted, above the eyes. There is a good deal of variation in this species, more in the female than in the male, the black being in many individuals of a brownish tinge.

Young Males.—Often of a brownish-black, like many of the females.

Female.—With the black generally of a brownish tinge, but often pale or greyish-yellow; sometimes the upper parts are pale yellow and the under parts and side of the head brown, and the area round the nude parts of the face white. (Anderson.)

Distribution.—Lower ranges of Bhutan—its furthest western range—(Pemberton); hill ranges of Upper Assam (Blyth), Sylhet, Chittagong, Aracan.

Habits.—"I first met with this species in Upper Burma," Dr. Anderson relates, "in passing through the magnificent defile of the Irawaddy, below Bhamo, where the river is enclosed by high hills, covered with dense forest, for about fifteen miles of its course. It was early morning, and the air was resonant with the loud cries of this Gibbon; large troops were answering each other from the opposite banks, and the hills echoed and re-echoed the sound. The Hoolock is also common on the Kakhyen hills, on the eastern frontier of Yun-nan; and there, too, my attention was called to them at daybreak, when they passed up from their sheltered sleeping-ground in the deep and warm valleys to heights of about 4,000 feet. We, in the middle distance, first caught a faint murmur of voices, but [ 163 ]every minute it became more and more distinct, till at last the whole troop rushed past in a storm of sound, vociferating Whoko! whoko! and in a few more minutes their cry was heard far up the mountain-side. Considering that their progress is almost exclusively arboreal, the rapidity with which they make their ascent is wonderful.

"Associated with this arboreal habit of progression, we find that H. hoolock derives its nourishment from leaves, insects, eggs, and birds, the essential features of sylvan life." It also eats the leaves of Ficus religiosa, the aquatic Convolvulus (Ipomœa reptans), and the brilliant red flowers of the Canna indica. It "has a marked partiality," continues the same naturalist, "for Spiders and their webs, which become tangled in its long slim fingers, and Orthopterous insects are regarded by it with special favour, and over which it utters its peculiar cry of satisfaction. Eggs also are to it a bonne bouche. It was first in the Calcutta gardens that I become aware of the circumstance that small living birds were devoured by it with a method and eagerness which has left no doubt in my mind that this species, in its natural state, must be a scourge to the feathery tribe."

The Hoolock lives in large flocks as a rule, keeping chiefly to the hill forests. Sometimes, however, an old male may be discovered living by himself.

They move chiefly by means of their long arms, by which they swing themselves for prodigious distances from branch to branch, and from tree to tree. They descend hill-sides at a surprising pace, their descent being accomplished by grasping bamboos or branches that bend beneath their weight, and allow them to drop until they can seize the ends of other bamboos or branches lower on the slope and take another mighty [ 164 ]swing downwards. They also ascend with great rapidity, swinging themselves from tree to tree. (Blanford.)

When walking on the ground the Hoolock rests on its hind feet alone, with the sole flat on the ground and the great-toe widely separated from the other digits. "They walk erect," writes Dr. Borrough, "and when placed on the floor, or in an open field, balance themselves very prettily by raising their hands over their head and slightly bending the arm at the wrist and elbows, and then run tolerably fast, rocking from side to side; and if urged to greater speed they let fall their hands to the ground and assist themselves forward, rather jumping than running, still keeping the body, however, nearly erect."


VI. THE HAINAN GIBBON. HYLOBATES HAINANUS.

? Hylobates pileatus, Swinhoe, P. Z. S., 1870, p. 224 (nec Gray).

Hylobates hainanus, Thomas, Ann. & Mag. Nat. Hist. (6), ix., p. 145 (1892).

Characters.—Very closely related to H. hoolock, but differs by the entire absence of the white superciliary streak, the animal being jet black all over.

Distribution.—The island of Hainan.

Habits.—This species has not been seen alive in its native haunts by any European naturalist. Consul Swinhoe made many efforts to obtain a living specimen in the island of Hainan, but was unsuccessful. "I never ceased," he says, "to enquire after it. Every one knew that such an animal did exist, and many had seen it; but they all spoke of the great difficulty of keeping it alive. At Taipingsze (Central Hainan) the wonderful stories that were told about it showed that the Yuen was not often seen there. The magistrate of that district assured me, [ 165 ]with a serious face, that it had the power of drawing into its body its long arm-bones, and that when it drew in one arm, it pushed out the other to such an extraordinary length, that he believed the two bones united in the body; and he said that the bones of the arm were used for chop-sticks." Mr. Swinhoe, however, published, in 1870, some curious extracts from the Chinese gazetteer of the Kiung-shan district of Hainan, which with little doubt relate to this interesting animal, of which skins have, since he wrote, been received at the British Museum, while a young individual lived for some months in 1893 in the Zoological Gardens of London, where it attracted much attention. The gazetteer says as follows: "Yuen: male black, female white; like a Macaque but larger, with the two fore-arms exceedingly long. Climbs to tree-tops and runs among them backwards and forwards with great agility. If it falls to the ground, it remains there like a log. Its delight is in scaling trees, as it cannot walk on the ground. Those desiring to rear it in confinement should keep it among trees; for the exhalations of the earth affect it with diarrhœa, causing death; a sure remedy for this, however, may be found in a draught made of the syrup of fried Foo-tsze (seeds of Abrus precatorius, Linn.)." The gazetteer then continues: "Hainan has also the Rock Yuen. It is small, about the bigness of one's fist. If allowed to drink water, it grows in size. This is also called Black Yuen, and is now likewise difficult to obtain."

Those who had an opportunity of observing the specimen that lived in the Zoological Gardens, will recall its extraordinary acrobatic feats, which were performed with marvellous precision and certainty, either with one or with both hands, and yet with the most careless air. It offered a striking contrast to an Orang-utan, which occupied the adjoining cage. This more [ 166 ]robust Ape exhibited in its arms equally perfect powers of climbing; but it moved with the greatest circumspection, deliberation, and composure, exhibiting none of the volatile activity so characteristic of the Gibbons; but moving only one pair of its limbs at a time, and only when the other pair had firm hold of some support.


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.

Plate XXXVIII.

THE SIAMANG GIBBON.


[ 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.

Plate XXXIX.

THE ORANG-UTAN.

[ 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.

Plate XL.

THE GORILLA.

[ 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.


I. THE COMMON CHIMPANZEE. ANTHROPOPITHECUS TROGLODYTES.

Homo sylvestris (Ourang-outang), Tyson & Cowper, Phil. Trans., xxi., p. 338 (1699); Tulpius, Observ. Anat., p. 270, pl. 14 (1641).

Homo troglodytes, Linn., Syst. Nat., i., p. 32 (1766; pt.).

Simia troglodytes, Gm., Syst. Nat., p. 26 (1788); Blumenb., Handb., x., p. 73 (1803); Owen, Tr. Z. S. I., p. 344, pls. 48, 50-52, 55, 56 (1835); ii., p. 169 (1841); Schl., Mus. Pays-Bas, vii., p. 8 (1876).

Troglodytes niger, Geoffr., Ann. Mus., xix., p. 87 (1812); Desmar., Mammolog., p. 49 (1820); Lesson, Spec. Mamm., p. 37 (1840); var. Marungensis, Owen, Tr. Z. S., v., p. 3, pls. i.-ix.; p. 279, pl. xlix. (1866); Noalk, Zool. Jahrb., ii., p. 291 (1887).

Pseudanthropos (Troglodytes) leucoprymnus, Less., Ill., Prod. Syst. Mamm., pl. 12 (1811); Reichenb., Naturg. Affen., p. 191 (1862).

Pithecus leucopryma, Less., Ill. Zool., pl. 31 (1836; young).

Satyrus lagaros, Meyen, Arch. f. Naturg., p. 282 (1856).

Mimetes troglodytes, Gray, Cat. Monkeys Brit. Mus., p. 6 (1870).

Troglodytes vellerosus, Gray, P. Z. S., 1862, p. 181; id., Cat. Monkeys Brit. Mus., Append., p. 127.

Troglodytes schweinfurthi, Gigl., Studii Craniol. sui Cimpanzé iii., p. 56 (1872).

Troglodytes aubryi, Grat. et Alix, Nouv. Arch. Mus., ii., p. 1, pls. 1, 9 (1866).

[ 195 ]Troglodytes tchego, Duvernoy, Arch. Mus., viii., p. 8 (1855).

Anthropopithecus troglodytes, Flower & Lydekker, Mamm., p. 736, fig. 357 (1891).

Characters.—Face, ears, hands, and feet dark-reddish flesh-colour, or more rarely of a blackish-brown colour; in general the colour of the hair is wholly black, except on the upper and lower lips, where it is white and very short, and in the region of the buttocks, where it is washed with reddish-brown.

Hair on the body straight and silky, with coarser hair interspersed; on the top of the head it lies smoothly to each side, away from a median line; round the face it forms bushy whiskers, extending down into a slight beard; it encroaches on the brow, leaving only a triangular central space naked; on the upper and lower lips are short, bristly hairs; the rest of the face naked and much wrinkled; on the shoulders, the back, and the hips, the hair is longer than elsewhere; the back of the hands and feet are thinly haired, the fingers and toes nude. The margin of the ears is often folded in for the greater part of its length.

The skin of the body is of a peculiar light, yet muddy, flesh-colour, sometimes verging on brown. Brownish or black spots on many parts of the body seem to vary in different individuals.

The expression of the face is grave, but less melancholy and pre-occupied than in the Orangs.

The weight of the brain in A. troglodytes varies from 6½ to 635 ounces.

This celebrated Man-like Ape has been known, by vague report at least, for nearly three hundred years. The earliest clear account of its existence, however, is derived from the "Strange [ 196 ]Adventures of Andrew Battell, of Leigh in Essex, sent by the Portugals prisoner to Angola, who lived there and in the adioining regions neere eighteene yeares." It was first published in 1613 in "Purchas his Pilgrimage," and later more fully in 1625, in "Purchas his Pilgrimes."[3] Here it is related that in the Province of Mayombe, "which is nineteen leagues from Longo along the Coast, the woods are so covered with baboones, monkies, apes, and parrots that it will fear any man to travaile in them alone. Here are also two kinds of monsters, which are common in these woods, and very dangerous. The greatest of these two monsters is called Pongo, in their language, and the lesser is called Engeco." The Pongo turned out to be the Gorilla, the description given by the old prisoner Battell proving to be wonderfully accurate. The lesser monster, the Engeco, is equally certainly the Chimpanzee. The first record of a specimen actually seen in Europe is in 1641, and is noticed by Tulpius in his "Medical Observations," and the earliest scientific description of a Chimpanzee—a young specimen of A. troglodytes—is that of the anatomists Tyson and Cowper, published by the Royal Society in 1699. It was, however, not till 1835, that the osteology of a full-grown specimen was described, when Sir Richard Owen's memoir appeared, and shortly after a very detailed account of its habits was given to the world by Dr. Thomas Savage, the missionary to whom we have already referred (p. 184), followed by a further anatomical investigation of its structure by Dr. Wyman, of Boston, U.S.A.

Distribution.—This species is found over the greater part of Tropical Central Africa, and its range is co-extensive with that given above for the genus. Loango and the Gaboon, however, [ 197 ]are the districts from which this Chimpanzee has chiefly been imported into Europe.

Habits.—The more characteristic habits of the common Chimpanzee have already been given under the description of the genus.

Its food consists of all sorts of forest fruits, and especially of the young shoots of the Scitamineæ, or ginger-plants.

The Chimpanzee can move the skin of its head, as the Gorilla does, but without causing the erection of the hair, which the Orang and the Gorilla are both able to accomplish. It can also to some considerable extent wrinkle its forehead, if disappointed or pleased, as when refused anything, or if tickled, when in the latter case it also utters a chuckling sound like that of smothered laughter, draws back the corners of its mouth, and wrinkles its eyelids.

The Soko observed by Livingstone in the Manuyema country would seem to be the common Chimpanzee. "According to Livingstone," to quote Mr. H. H. Johnston's note in his excellent "Life" of the great traveller, "these creatures often walk in an erect position, but steady their bodies by placing the hands on the back of the head. He represents this beast as being of great intelligence, and so cunning, that it is difficult to stalk him in front without being seen, and, therefore, when he is killed, it is usually from behind. The Manuyema people frequently string a number of nets round some enclosure in the forest and drive the Sokos into them and spear them. Brought to bay like this, they will frequently turn on their assailants, and will snatch their spears from them, and break them, and perhaps also bite off the ends of the men's fingers. But, as a rule, the Soko is not ferocious. They are said to kidnap children and [ 198 ]run up the trees with them, and have to be lured down by bananas. When wounded the creature tries to staunch the blood by stuffing leaves into the wound. It lives in communities of about ten, and is monogamous. The female produces occasionally twins. As parents, they are very affectionate towards their offspring, the father relieving the mother of the burden of her young one in dangerous places. Their food consists of wild fruits. At times the Sokos collect together and drum with their fists on the trunks of hollow trees, and accompany this performance with loud yells and screams."

"According to the statements of the Niam-niam themselves," says Schweinfurth, "the chase of the Chimpanzee requires a party of twenty or thirty resolute hunters, who have to ascend the trees, which are some eighty feet high, and to clamber after the agile and crafty brutes until they can drive them into the snares prepared beforehand. Once entangled in a net the beasts are without much further difficulty killed by means of spears. However, in some cases, they will defend themselves savagely and with all the fury of despair. Driven by the hunter into a corner, they are said to wrest the lances from the men's hands and to make good use of them against the adversary. Nothing was more to be dreaded than being bitten by their tremendous fangs." The stories as to their carrying off young girls, and constructing nests are pure fabrications, according to Schweinfurth. Its name among the Niam-niam is "Ranya." "The life which the Ranya leads is very much like what is led by the Orang-Utan in Borneo, and is spent almost entirely in the trees, the woods on the river banks being the chief resort of the animals.... Like the Gorillas, they are not found in herds, but either in pairs, or even quite alone, and it is only the young which occasionally may be seen in groups."


PLATE XLI.

Plate XLI.

THE BALD CHIMPANZEE.


[ 199 ]

II. THE BALD CHIMPANZEE. ANTHROPOPITHECUS CALVUS.

Troglodytes calvus, Du Chaillu, Pr. Bost. Soc. Nat. Hist., vii., p. 296 (1861); id., Travels, pp. 32, 48, 63 (1861); Gray, P. Z. S., 1861, p. 273; Bartlett, P. Z. S., 1885, p. 673, pl. xli.; Beddard, Tr. Z. S., xiii., p. 177 (1893); Romanes, P. Z. S., 1889, p. 316.

Troglodytes kooloo-kamba, Du Chaillu, Pr. Bost. Soc. Nat. Hist., vii., p. 358 (1861); id., Travels, pp. 39, 49, 50 (1861); Gray, P. Z. S., 1861, p. 273.

Mimetes troglodytes, var. a (T. calvus), Gray, Cat. Monkeys Brit. Mus., p. 6 (1870).

Anthropopithecus calvus, Flower & Lydekker, Mammals, p. 736 (1891).

(Plate XLI.)

Characters.—This species was first indicated by Du Chaillu on his return from his celebrated journey to the Gaboon, but based on poor skins, which left much doubt as to the species being distinct. Excellently preserved specimens were, however, brought home by Marche and Dr. Compiégne, and some of them passed into the Dublin Museum, but it was not till 1885, when a living specimen, now known to fame as "Sally," was received at the Zoological Gardens in London, and lived there for five years, that the correctness of Du Chaillu, as to the distinctness of his "Kooloo-kamba," A. calvus, from A. troglodytes, was proved and accepted.

Similar to A. troglodytes, but distinguished from it by the face, hands, and feet being quite black, or brownish-black, instead of pale flesh-colour; the front, top, and sides of the head and face are nearly naked, having only a few short hairs on the head, which is quite destitute of any signs of the parting so [ 200 ]conspicuous in A. troglodytes. The hair is blacker than in the latter species, and extends only for a short distance in front of the level of the ears, and on the sides of the face; the temporal region and cheeks show a scanty growth; on the chin and upper lip a sparse crop of short hairs, chiefly white; long scattered black eyebrows, which do not meet in the mid-line, spring from the supra-orbital ridges. The ears are as large as in A. troglodytes, very flat, but stand out more prominently from the side of the head; their margin is nude, and there is no lobule. The hands are haired across the knuckles, and again (after a naked band) on the back of the hand and arm; the foot is haired down to the first joints of the toes; the nails and fingers are very human in appearance.

Face very prognathous; the nasal bones ridged in the mid-line; the foot less like a human hand than even in the Orang. "Sally's" brain weighed 835 ounces.

The expression of the face, the expanded nostrils, the thicker lips, especially the lower lip, and the more elevated skull, all distinguish A. calvus from A. troglodytes; in its muscular anatomy and in its brain it also shows points of difference.

Distribution.—The interior of Gaboon, in Western Africa.

Habits.—The Bald Chimpanzee showed in captivity a disposition to live on animal food, which the Common Chimpanzee never does. "Sally" had also the singular habit of producing pellets, resembling the castings thrown up by Raptorial birds; they were composed of feathers (of the birds she had eaten) and other indigestible substances taken with her food. Moreover, "Sally," as this Chimpanzee, now famous in the annals of zoology, was named, was an expert rat-catcher, and caught and killed many rats that entered her cage. "Her intelligence was [ 201 ]far above that of the ordinary Chimpanzee. With but little trouble she could be taught to do many things that require the exercise of considerable thought and understanding." (Bartlett.) In general habits A. calvus differs, so far as known, in no respect from A. troglodytes.

It was on this Ape that the late Dr. G. J. Romanes, attracted by its high intelligence, made his interesting psychological experiments, which are related in the Proceedings of the Zoological Society for 1889. "Her intelligence was conspicuously displayed by the remarkable degree in which she was able to understand the meaning of spoken language—a degree fully equal to that presented by an infant a few months before emerging from infancy, and, therefore, higher than that which is presented by any brute, so far at least as I have met with any evidence to show. Having enlisted the intelligent co-operation of the keepers, I requested them to ask the Ape repeatedly for one straw, two straws, or three straws. These she was to pick up and hand out from among the litter of her cage. No constant order was to be observed in making these requests, but whenever she handed a number not asked for, her offer was to be refused, while if she gave the proper number her offer was to be accepted, and she was to receive a piece of fruit as payment. In this way the Ape was eventually taught to associate these three numbers with their names.... As soon as the animal understood what was required, and had learnt to associate these three numbers with their names, she never failed to give the number of straws asked for. Her education was then extended in a similar manner from three to four and four to five straws." "Sally" rarely made mistakes up to that number, but above five and up to ten, to which one of the keepers endeavoured to advance her education, the result is uncertain. [ 202 ]"It is evident that she understands the words seven, eight, nine, and ten, to betoken numbers higher than those below them, and when she was asked for any of these numbers above six, she always gave some number over six and under ten. She sometimes doubled over a straw to make it present two ends, and was supposed to hasten, with the small stock of patience she possessed, the attainment of her task." Dr. Romanes was disposed to think that the uncertainty which attended her dealing with the numbers six and seven was due to her losing patience rather than to her losing count. It was at all events evident that "Sally" could count accurately up to five. Dr. Romanes tried to teach her colours in the same way, but the result was so uniformly negative that he was disposed to think that she was colour-blind, as she was taught to distinguish between white straws and the straws of any other colour, but she could not be taught to go further.

In 1875 a female Ape, which received the name of "Mafuca," was received from the Loango coast at the Dresden Zoological Gardens. "This," says Dr. Hartmann, "was a wild unmanageable creature, 120 cm. in height, reminding us in many respects of the Gorilla. The face was prognathous [more so than in A. troglodytes]; the ears were comparatively small, placed high on the skull, and projecting outwards; the supra-orbital arch was strongly developed, and the end of the nose was broad, and there were rolls of fat on the cheeks. The creature was, moreover, strongly built, and the region of the hips and the belly was contracted, while the hands and feet were large and powerful. The general physiognomical resemblance between Mafuca and a female Gorilla [whose dead body I had examined] was very great." It was suggested that the creature might be a cross between a Chimpanzee and a Gorilla, as the traveller [ 203 ]Koppenfels had affirmed he had shot such cross-bred animals. It is still an undecided question to what species it belonged.

Of the four genera of the Simiidæ, "the Gibbons are obviously most remote from Man, and nearest to the Cynopithecini (Cercopithecidæ).

"The Orangs come nearest to Man in the number of the ribs, the form of the cerebral hemispheres, the diminution of the occipito-temporal sulcus [groove] of the brain, and the ossified styloid process; but they differ from him much more widely in other respects, and especially in the limbs, than the Gorilla and the Chimpanzee do.

"The Gorilla is more Man-like in the proportions of the leg to the body, and of the foot to the hand; further, in the size of the heel, the curvature of the spine, the form of the pelvis, and the absolute capacity of the cranium.

"The Chimpanzee approaches Man most closely in the character of its cranium, its dentition, and the proportional size of the arms." (Huxley.)


  1. Specimens of Anthropopithecus niger and Gorilla gorilla, in the Derby Museum, Liverpool, in which the permanent teeth have not yet developed, have the premaxillary suture quite obliterated.
  2. The deformity known in the human skull as acrocephaly, which occurs in all races of men, and is due to the too early ossification of certain of its sutures, has been found in the Chimpanzee.
  3. Huxley's "Natural History of the Man-like Apes," p. 5.