The Cambridge Natural History Part 48

An a.n.a.logous annectent character is shown by the Italian fossil, _Oreopithecus bambolii_. This animal was referred by one palaeontologist to the Man-like Apes, by another to the Cercopithecidae. It suggests a common ancestral form, and is Middle Miocene in horizon.

Just as there are no Platyrrhine Apes in the Old World so there are no Catarrhines met with in a fossil condition in the New World; the two great divisions of the Apes were as distinct in the past, so far as we know, as they are now--a strong argument in favour of those who would derive them from two sources. The {570} existing genera, _Cebus_, _Mycetes_, and _Callithrix_, now living in South America, are also known in a fossil state. The extinct genus _Homunculus_ is known from the Tertiary strata of Patagonia, and an apparently allied form is _Anthropops_. These creatures, however, are at present far from exhaustively known.

FAM. 2. SIMIIDAE.--The Anthropoid, or Man-like Apes,[436] may be separated from the lower Apes as a group, Simiae, or perhaps better, on account of the after all slender points of difference, a family Simiidae, which has the following distinctive characters.

Though arboreal creatures for the most part, these Apes, when they come to the ground, progress in at least a semi-erect fashion. Moreover, when they, as is usually the case, put their hands upon the ground to aid in walking, they do not rest as do the lower Apes upon the flat of the hand, but upon the back of the fingers. None of the Anthropoids has a tail, or cheek pouches. Ischial callosities are only seen in the Gibbons. There is commonly a laryngeal pouch, which is of large size, and aids in the production of the generally loud voice of these creatures. The hair is rather more scanty than in the Cercopithecidae, which is an approach to Man. The placenta differs in detail from that of the lower Apes, and is exactly like that of Man. These Apes show as further differences from the underlying Cercopithecidae, the greater length of the arms as compared with the legs, and the presence of a vermiform appendix to the caec.u.m. In the latter but not the former character they agree with Man, whom we shall place in a separate family, Hominidae. The Anthropoid Apes are entirely Old World and intratropical in range at the present time.

The Gibbons, genus _Hylobates_, stand quite at the base of the series of existing Anthropoid Apes. They are the smallest and the most purely tree-frequenting of all the members of that group. Connected with this habit is the structural peculiarity that their arms are proportionately longer than in the other Anthropoids. The affinity of the Gibbons to the Catarrhines is proved by the presence of distinct but small ischial callosities. The arms are so long that when walking upright the hands reach the ground. The hallux is well developed. The ribs are thirteen pairs. In the skull the chief noteworthy character as {571} compared with other Anthropoids is the fact of the large size of the canines, which are of equal or nearly equal size in the two s.e.xes. The molars on the other hand have been particularly compared to those of Man. The brain is simpler than in the higher forms. But it is not clear that this may not be a case of diminished complexity of convolution going hand in hand with smallness of size.

[Ill.u.s.tration]

FIG. 272.--Hoolock. _Hylobates hoolock._ 1/6.

The Gibbons range through south-eastern Asia from a.s.sam and Burmah to Hainan. The number of species is a little doubtful. It is clear that in the first place we may distinguish the Siamang, _H. syndactylus_, which indeed some regard as a separate genus. It is mainly to be defined by the syndactylous character of the second and third toes; they are united by skin as far as the last joint. The Hainan species, _H. haina.n.u.s_, is probably distinct, and the following names have been given to various other species or races, viz. _H. agilis_, _H. leuciscus_, _H. leucogenys_, _H.

lar_, _H. hoolock_. These animals can walk erect; and when they do so, the big toe is separated as in unsophisticated or at least unbooted man. The voice is well known to be loud, {572} and it is a curious fact that the Siamang, which has a large laryngeal pouch, is not excelled in this respect by species in which this sac is not developed.

[Ill.u.s.tration]

FIG. 273.--Cerebrum of the Gibbon (_Hylobates_). (Lateral aspect.) _c.c_', _c.c_", Anterior and posterior central convolution; _fi_, interparietal fissure; _fr_, frontal lobe; _f.s_, Sylvian fissure; _oc_, occipital lobe; _pa_, parietal lobe; _s.c_, fissure of Rolando; _tp_, temporal lobe; *, fronto-orbital fissure. (From Wiedersheim's _Structure of Man_.)

Of Gorillas, genus _Gorilla_, there is but one species, which must apparently and rather unfortunately be called _Gorilla gorilla_.

The misfortune is double: in the first place the repet.i.tion of the same word as both generic and specific appellation is tiresome to the ears and barbarous in its suggestion; in the second place it is now well known that the "Gorilla" of Hanno, observed by that Carthaginian voyager on an island off the African coast, was not a Gorilla at all as the word is now understood, but probably a Baboon. The external aspect of this great Anthropoid is familiar from many reproductions. The male, as is usual, is larger than the female, and his characters are more p.r.o.nounced.

The face is naked and black, and the skin generally is deep black, even at birth. The ear is comparatively small, and is adpressed to the side of the head; it is altogether more human in form than that of the Chimpanzee, and this statement applies also to the rudimentary condition of the muscles of the ear, which are more rudimentary than in the Chimpanzee. The nose has an obvious median ridge, and is thus p.r.o.nounced as an external feature; the nostrils are very wide. The hands and feet are short, thick, and broad; the digits are webbed. In the foot the heel is more apparent than in other Anthropoids. It is not, {573} however, so marked as in Man, and the phrase "Ex pede Herculem" has been aptly supplemented by "Ex calce hominem." The hair upon the head forms a kind of crest, which can be elevated when the animal is enraged. The neck is thick and short, and the beast has ma.s.sive shoulders and a broad chest.

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FIG. 274.--Gorilla. _Gorilla gorilla_, [female]. 1/8.

If it were not for the fewness of the Anthropoid Apes, and their nearness to Man, it is doubtful whether the Gorilla would be ranked as a distinct genus,[437] for in internal structure it is very near the Chimpanzee. The microscopic character of the investigations into the anatomy of Man have somewhat dimmed the proper sense of perspective, and have tended to throw into greater prominence than seems necessary the divergences of structure seen in the Gorilla. Dr. Keith[438] has recently summed up and commented upon these divergences, and the following account of this Anthropoid is mainly deduced from his memoir.

The cranial capacity of the Gorilla is greater than that of the Chimpanzee.

It is not possible, however, to decide from this point of view whether a given skull is that of one or of the other of these Apes. Some Chimpanzees are higher in capacity {574} than some Gorillas. But the average is undoubtedly as stated. It is to be noted that there is a correspondence between cranial capacity and size of palate, the correspondence being converse, _i.e._ the greater the brain the smaller the palate. This applies to Man as compared with his Ape-like relatives, but does not apply so accurately to the Gorilla, which has a more extensive palate than the Chimpanzee; its "brute development" is much greater than that of the Chimpanzee. Not only is the palate larger, but the molar teeth, slightly different in form, are also larger and stronger. This is so plainly marked that "one may say almost with certainty, that any upper molar tooth over 12 mm. in length is that of a Gorilla, and under 12 mm. is that of a Chimpanzee." In the skeleton generally it may be said that the crests for muscular attachments upon the bones are greater in the Gorilla. The nasal bones are more like those of lower Apes in their length, and they have a sharp ridge more marked than in the Chimpanzee, which, however, disappears in aged animals. It is a curious fact that Gorillas often have a "cleft palate," owing to the failure of the palatal part of the palatine bones to meet completely. The general conformation of the skull is less brachycephalic in the Gorilla.

The limbs show a number of small differences, which are a.s.sociated with a more completely arboreal life in the Chimpanzee as compared with the Gorilla. The latter is approaching the human way of life. In spite, however, of these differences, no hard and fast lines of divergence can be laid down between the two African Anthropoids, for it appears from the many memoirs that have been written upon both that "there is scarcely a feature in any muscle or bone found in one animal which is not also found in the other." The heel of the Gorilla has already been referred to. This is, of course, a.s.sociated with a plantigrade and therefore non-arboreal mode of progression. Certain of the muscles of the calf of the leg attached to the heel show a more human arrangement in the Gorilla than in the Chimpanzee.

It is interesting to find that the muscles of the little toe are diminishing in the Gorilla as in Man. This is most clearly due to terrestrial progression and we may apply the same explanation to Man and ignore tight boots! The arm of the Gorilla is less adapted to arboreal progression. Its proportions differ from those of the arm of the Chimpanzee in that the fore-arm is shorter. In {575} both animals the thumb is not of much use, and this digit is more retrograde in the Gorilla, not only in proportionate length but in its muscular supply. The hip girdle tells the same tale. It is broader in the Gorilla, and the glutaei muscles are more prominent, all these features being connected with the more erect gait.

The brain of both animals have been studied, but not in the case of the Gorilla from a sufficiently large number of examples to make any generalisations of great value. On the whole, the Gorilla has the larger brain, but this must be discounted by the fact that it also has the larger body. It is a remarkable fact that the Gorilla's liver is much more like that of lower Apes than the liver of other Anthropoids. It has, as has the Chimpanzee, laryngeal sacs. The general conclusion concerning the relative position of the two African Anthropoids seems to be that the Gorilla is the more primitive; and as thus it must approach more nearly to the original parent than does the Chimpanzee, it may be said that it also comes rather nearer to Man, since the Chimpanzee has travelled away from the common stock on another line. The detailed likenesses to Man, however, are not to be unduly dwelt upon; for they mainly come from a tendency to a.s.sume the plantigrade mode of progression.

In mental characteristics there is the widest difference between the two Apes that we are considering. The Chimpanzee is lively, and--at least when young--teachable and tameable. The Gorilla, on the other hand, is gloomy and ferocious, and quite untameable. When angry the Gorilla beats its breast, a statement that was originally made, we believe, by M. du Chaillu, but which has been disputed, though it appears to be perfectly true. A young Gorilla, exhibited some time since in the Gardens of the Zoological Society, could be observed to do so. The cry of the Chimpanzee is different from the "howl" of the Gorilla. An immense amount has been written upon the ways of this animal in its own home, including much that is legendary. The Gorilla has been said to lurk in the depths of the forest, and to stretch down a prehensile foot to grasp and strangle an unfortunate black man pa.s.sing below. It is said, too, to vanquish the Elephant by hitting it hard upon the trunk with a stout stick, and to crumple up the barrel of a rifle with its powerful teeth. {576}

Apart from the doubtful "Pongo" and "Engeco" of Andrew Battel, our first intelligence concerning the Gorilla is due to Dr. Savage, after whom, indeed, the late Sir Richard Owen called the animal _Troglodytes savagei_, a name which has to be abandoned in favour of an earlier name.

The Gorilla is limited in its distribution to the forest tract of the Gaboon. It goes about in families, with but one adult male, who later has to dispute his position as leader of the band with another male, whom he kills or drives away, or by whom he is killed or driven away. The animal is said to make a nest in a tree like the Orang; but this statement has been questioned.

It feeds upon the berries of various plants, and upon other vegetable substances; there is apparently not so marked an inclination for animal food as is exhibited by the Chimpanzee. In search of their food they wander through the forest, walking partly upon the bent hand, and progressing with a shuffling gait. It is noteworthy that the Gorilla has been said to walk upon the palm of the hand and not upon the back, as is the case with the Chimpanzee. It can readily a.s.sume the upright posture, and, in this case, balances itself largely with its arms. Professor Hartmann, however, states that the back of the hand is also used. Unlike most or many wild beasts, the Gorilla exhibits no desire to run away when he views a human enemy. Dr.

Savage remarks that "when the male is first seen, he gives a terrific yell, that resounds far and wide through the forest, something like kh-ah! kh-ah!

prolonged and shrill." This is accompanied by offensive tactics, which the natives do not willingly encounter. When making an attack the Gorilla rises to his feet, and as a full-grown animal reaches a height of some five feet, he is a most formidable antagonist. The attack of one of these animals is said to be made with the hand, with which he strikes his adversary to the ground, and then uses the powerful canines. The beating of the breast which heralds an attack is a statement made by M. du Chaillu. It has been denied with a vigour and asperity quite incommensurate with the importance of the matter.[439]

[Ill.u.s.tration]

FIG. 275.--A, Cerebrum of a female Chimpanzee two years old. . (Dorsal aspect, showing asymmetrical development.) _c.c_', _c.c_", Anterior and posterior central convolutions; _f.i_, interparietal fissure; _f.l_, the longitudinal fissure; _f.po_, parieto-occipital fissure; _fr_, frontal lobes; _oc_, occipital lobes; _s.c_, sulcus centralis. B, Brain of a female Chimpanzee two years old. . (Lateral aspect.) _cb_, Cerebellum; _c.c_', _c.c_", anterior and posterior central convolutions; _fr_, frontal lobe; _f.s_, fissura Sylvii; _is_, island of Reil; _md_, medulla oblongata; _oc_, occipital lobe; _pa_, parietal lobe; _s.c_, sulcus centralis; _tp_, temporal lobe. (From Wiedersheim's _Structure of Man_.)

The Chimpanzees, genus _Anthropopithecus_ (or _Troglodytes_), are {577} to be distinguished from the Gorilla by the characters mentioned in the account of the latter animal. Briefly summed up they are mainly as follows:--The ears are large, and generally stand out from the head; but there are exceptions to be noted {578} presently. The pigmentation of the body is not always so p.r.o.nounced as in the Gorilla. The nasal bones are shorter. The skull as a whole is more brachycephalic, and the molar teeth are smaller. The hands and feet are much longer, the animal being more purely arboreal than the Gorilla. The female Chimpanzee is slightly smaller than the male, but the great disparity observable in the Gorilla does not characterise its ally. The animal, like the Gorilla, has large air sacs.

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FIG. 276.--Skull of Chimpanzee. _Anthropopithecus troglodytes._ 1/3.

(After de Blainville.)

Chimpanzees are entirely restricted to Africa, and though they appear to extend rather farther east than the Gorilla, the forest-clad region of the equatorial belt is their home.

It has been mentioned in treating of the Gorilla that the main feature of this animal, which affords a constant difference from the Chimpanzee, is its gloomy and ferocious manner. The Chimpanzee, on the other hand, is lively and playful, though often maliciously so, and quite tameable, as many instances--particularly the notorious "Sally" of the Zoological Gardens--show. The earliest mention of animals that are probably Chimpanzees is to be found in a work upon the Kingdom of Congo, published in 1598. In a cut ill.u.s.trating that work, and of {579} which a part is reproduced in Professor Huxley's essay referred to below,[440] the Apes, which correspond roughly in their appearance to Chimpanzees, are represented as being captured by the device of limed boots, which the Apes are putting on. This idea has been subsequently imitated and acted upon. A little later, Andrew Battel wrote of the Pongo and of another creature the Engeco. This latter, whatever may be the case with the former, is in all probability the Chimpanzee, since the word 'Nchego, now applied to those creatures, seems to be the same word. From this seems also to be derived the sailor's term "Jacko." Whether there are or are not more than one species of Chimpanzee, is a matter which has exercised and perplexed naturalists. That there are plain differences of external features, at any rate between individuals, is perfectly clear. We are justified in recognising three forms, but the question of their specific distinctness may for the present be held in reserve. The commonest of these is the variety known as _A. troglodytes_. This is frequent in menageries, though the specimens on view are nearly always young and small. The face and the hands are flesh-coloured, and the ears are very large. The black hair gets a reddish tinge on the flanks. The second variety is that which was termed by du Chaillu _Troglodytes kooloo-kamba_. This animal appears to be also the _T. aubryi_ of MM. Gratiolet and Alix,[441] and to be identical with two Apes known by the names of "Mafuca" and "Johanna."[442] The former of these was exhibited in Dresden, the latter at Messrs. Barnum and Bailey's show. The two animals have been carefully studied. They differ from the common Chimpanzee by the dark colour of the face, and in the case of Mafuca the ear was Gorilline in form. So too was the ear of _A. aubryi_, while Johanna has a larger one. These features have led to the suggestion that the Kooloo-kamba was the result of a mesalliance between a Gorilla and a common Chimpanzee.

It has at any rate been stated that the two Anthropoids do go about in company; but there seems to be little doubt that there is no question here of a hybrid. Dr. Keith's careful studies[443] upon Johanna have demonstrated the impossibility of {580} regarding this Ape as anything but a Chimpanzee. The animal has the ways and manners of the Chimpanzee; has a cry exactly like that of _A. troglodytes_; does not beat her breast like a Gorilla when annoyed. Anatomical knowledge, however, of this specimen is at present wanting.

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FIG. 277.--Young Orang-Utan. _Simia satyrus. Zeitschrift fur Ethnologie_ (_Anthropolog. Gesellschaft_), Bd. viii. (From Wiedersheim's _Structure of Man_.)

_Anthropopithecus calvus_[444] seems to be at least as much ent.i.tled to distinction as the last. It was originally described by du Chaillu; but Dr.

Gray who examined the skins thought that the baldness was accidental, and then after this wise caution proceeded to describe, under the name of _A.

vellerosus_, perhaps the "worst" species of Chimpanzee that has been added to the unnecessarily long list of "species" of Chimpanzees. To this variety belonged "Sally"[445] of the Zoo, whose intelligence has been celebrated by the late Dr. Romanes. The form is characterised {581} by its intense blackness, the red reflection of other Chimpanzees not being visible; also by the bald head, whence of course the name. The nostrils of this Ape, as of Johanna, were somewhat expanded, and thus present a certain likeness to the Gorilla. But there can be no suggestion that _A. calvus_ is the product of a union between the two African Anthropoids. As is the case with Johanna, Sally was given and enjoyed animal food on occasions. It is a curious fact that both Sally and Johanna appear to have been colour-blind.

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FIG. 278.--Young Orang-Utan. _Simia satyrus. Zeitschrift fur Ethnologie_ (_Anthropolog. Gesellschaft_), Bd. viii. (From Wiedersheim's _Structure of Man_.)

The Orang Utan, genus _Simia_, has but one definable species, viz. _S.

satyrus_. The supposed species of Owen, _S. morio_, cannot be satisfactorily defined. Plenty of other specific names have also been given to what is in all probability but a single species of large Anthropoid Ape inhabiting the islands of Borneo and Sumatra. {582}

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FIG. 279.--Skeleton of Orang. _Simia satyrus._ (After de Blainville.)

The name Orang-Utan, now applied exclusively to the subject of the present description, was formerly applied also to the Chimpanzee, and to that animal, moreover, under the latinised version of _h.o.m.o sylvestris_. The Orang is a large and heavy Ape with a particularly protuberant belly and a melancholy expression. The face of the old male is broadened by a kind of callous expansion of naked skin at the sides. The colour of the animal is a yellow brown, varying in the exact shade. The ears are particularly small and graceful in appearance, pressed closely to the sides of the head. The head is very brachycephalic. The arms are very long, and when the animal is in the erect posture they reach as far as the ankle. The hallux is very short and usually dest.i.tute of a nail. It is a curious fact that the head of the thigh bone is unattached by a ligament to the socket of the pelvis in which it articulates, a state of affairs which may give the limb greater freedom in movement, but does not add to its strength; {583} indeed, the Orang has been described as moving with laborious caution.

This Ape inhabits flat and forest-clad ground, and lives mainly in the trees. The male leads a solitary life except at the pairing season, but the female goes about with her family. On the ground the Orang walks with no great ease, and uses his arms as crutches to swing the body along. Even on trees the rate of progress is not rapid, and is accomplished with careful investigations as to the capabilities of the branches to bear his weight.

The "Man of the Woods" has been stated to build a hut in trees. This is an exaggeration of the fact that it constructs a temporary nest.

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FIG. 280.--A, Skull of a young Orang-Utan. _Simia satyrus._ (One-third natural size.) B, Skull of an adult Orang-Utan. (One-third natural size.) (From Wiedersheim's _Structure of Man_.)

One of these nests has lately been described elaborately by Dr. Moebius. It was found (by Dr. Selenka) on the fork of a tree at a height of 11 metres from the ground. Every night, as it appears, or every second night, the animal constructs a new nest for himself, abandoning the old one. So numerous, therefore, are these nests in localities frequented by Orangs, that a dozen can be readily found in a day. The particular nest which Dr.

Moebius examined was 1.42 metres long, and at most .80 metre broad. It was built of about twenty-five branches, broken off and laid for {584} the most part parallel to each other. Above this framework a number of loose leaves lay. There is no doubt, therefore, that these nests are not by any means elaborate structures, and that they only serve as sleeping-places, and not as nurseries for the upbringing of the young, as has been a.s.serted.