CHAPTER VII. On the Way Upward

ON THE WAY UPWARD

BRAINS OF THE OLD WORLD MONKEYS

We have seen that the first steps leading to improvements in the primate brain were taken by certain humble creatures living in distant parts of the earth, and by the great tribes of the New World monkeys inhabiting South America and Central America. These steps did not lead far along the path of progress. They were only a beginning, the first harbingers of man’s arrival. Many lowly animals in the ape house at the zoölogical gardens reveal numerous features suggestive of the human being. Such features not only include their fingers, finger nails, toes and toe nails, but even more their facial appearance. Many of these monkeys look like diminutive old men. They snarl and show their teeth when angry. Their way of indicating displeasure is almost human. They make certain expressive gestures, like nodding or tilting of the head to one side in a quizzical or even pathetic manner. They make plaintive cries or sounds, in some cases almost like the notes of a bird, or they scream out loudly in anger. All of these New World monkeys are notable for one other reason. They do not make any of those humorous grimaces that are so amusing in the Old World monkeys. These latter manifest a certain drollness in their constantly changing facial expression.

The Old World monkeys include about three quarters of all living species. They are embraced in one great family, but the members of this family show many differences ranging from the huge dog-faced baboon to the small bonnet monkey. Some of them are gentle and affectionate, some are savage, pugnacious, and treacherous. This entire family is spread out over the hot or semitropical regions of the world. Many of its members live in the damp, tropical forests; others prefer rocky, almost barren country, and a few seek their homes in temperate climates. Some monkeys are found among the lower ranges of the Himalayas and may be seen in the winters playing among the branches of snow-laden trees. Two varieties seem to have a surprising endurance in really severe cold. They inhabit the elevated regions of eastern Tibet.

In picturing to ourselves the characteristics of a monkey we are apt to have the conception of an animal that can hold on and hang by its tail. None of the Old World monkeys has this kind of tail. The greatest number of them live in the trees, and the tail, while generally short and stumpy, in some cases is decorative and almost plume-like. Most of the Old World tribes are especially interesting and amusing because of a large elastic pouch in each cheek. This pouch the monkey greedily crams with food in his haste to get his meal into safe-keeping. When the cheek pouches are filled both cheeks are bulged out and give the animal somewhat the appearance of a gourmand embarrassed by a mouthful of delicacies. Later on, at his leisure, the monkey chews and swallows the food.

Baboons

By far the largest of the Old World monkeys are the baboons. They may be recognized at once by three characteristics. The head and face look much more like those of a dog than is true of other monkeys. They have long and dangerous fangs in the upper and lower jaws. They go about, like most four-legged animals, upon hands and feet which have much the appearance of paws.

Further acquaintance with the baboon shows him to be a surly, unmannerly, savage, and thoroughly undependable creature. All of his tribes have fleshy pads over the buttocks, which in some cases are large and brilliantly coloured. Some members of his clans, such as the mandrill, have faces which look like gruesome masks or hideously painted savages. The skin over the nose is a fiery red, while the cheeks are swollen, ribbed, and of a vivid blue colour. A beard of golden hue hangs beneath the chin in contrast to the dull olive drab of the body. Protruding over the lips are savage canine teeth, long and dagger-like. These baboons are about as large as a good-sized dog. The colouring of the face adds considerably to the repulsive unattractiveness of the animal. They run along on their hands and feet, with their eyes directed downward, so that they are obliged to elevate the large overhanging eyebrows in order to look upward and forward. They go about with the palms of the hand and soles of the feet laid flat upon the ground. The mother is often seen walking or scampering around with a young baboon clinging to her back. Sometimes the mother will sit up on top of a rock just like a human being. Her offspring often perches on her neck after the fashion of a well-trained acrobat.

All of these monkeys are gregarious. They travel about in large numbers. Often as many as a hundred individuals collect in one herd. Because of their aggressive disposition, they are dangerous enemies, especially when irritated or disturbed. Their long, sharply pointed, canine teeth are capable of inflicting severe wounds. Although they have no actual speech, they utter certain sounds that seem to be thoroughly understood by all members of the herd. There is quite a variety in these sounds. Some of them resemble barks, grunts, or even screams. Often they make low and subdued murmurs with various inflections, the meaning of which all the baboons seem to understand immediately. Sometimes the slightest murmur from one of the members of the herd will act as a signal or warning. This is particularly true when the baboons are out on an expedition of pillage or mischief. On such occasions they always station a lookout or outpost at some favourable point from which the signal may be given upon the approach of danger. The faintest murmur made by one of these lookouts will start the marauding baboons scampering away to safety.

Disposition of Baboons

For the most part they live in rocky places near ravines, crags, or hilly promontories where grass and trees are scanty. Their favourite abodes are usually places surrounded by wide plains. This kind of home enables them to lie in wait for the right moment to perpetrate some thieving expedition upon a garden or field and at the same time to have every opportunity of escape. They are much given to mischief of this kind. Consequently they are feared and despised by the inhabitants of the country which they infest. If attacked, they often turn upon their pursuers and inflict serious wounds upon their assailants. Some baboons prefer to live in the dense forest and climb readily about even in the tallest trees. Those that live in more open country are very agile in clambering among the rocks and are able to reach lofty heights or positions of safety. The baboon eats a little of everything, although its chief diet consists of roots, fruits, reptiles, and insects. To procure their food they are continually searching, turning over stones beneath which the desired food may be concealed. When young the baboon is often quite gentle and affectionate, but with most of them this disposition changes when they grow up. In captivity baboons are surly and unfriendly. Even those born and reared in captivity are more difficult to approach and teach than other apes. They are vindictive and treacherous. Their disagreeable dispositions accord well with their unpleasant and often repulsive facial expressions. Their savage reactions and lack of intelligence have earned for them the reputation of being the lowest of the Old World monkeys. Baboons seldom assume the erect position for standing or walking. They do, however, sit upon their haunches in a somewhat crouched position, but not so freely as many other Old World monkeys. They all live in Africa, with a slight extension into Arabia. It is well that these animals never grew to the size of the great apes, for had they done so they certainly would have been among the most dreaded and frightful creatures ever known on earth.

Dr. Ditmars, who has spent much time in observing monkeys, reports many interesting studies and experiments concerning their behaviour. Apparently the habit of throwing missiles when enraged is not uncommon among baboons. Any angry monkey may in its rage grasp and hurl an object such as a drinking pan, but there is usually no accuracy in its aim or intention in its act other than an expression of irritated feelings. None of the monkeys has ever been known to use a stick or a club in attacking others or defending itself. Although the throwing of missiles is almost unknown among monkeys, the baboon marks an exception. As an instance, one day Dr. Ditmars found the visitors to the ape house almost in a panic, due to the savage behaviour of a big yellow baboon. A part of the cement had fallen out of the wall of his cage and broken up into sharp pieces. These pieces the baboon was hurling at the visitors through the bars in a most deliberately offensive manner and with effective aim. The crowd in consequence had retreated to various points of safety. Later a shovelful of coal was placed in the cage of this same baboon. The pieces of coal he also used as missiles, throwing them with calculating aim at the keeper and other attendants. The baboon seems to have an excellent throwing arm, and Dr. Ditmars credits him with good control and much speed. During this experiment a baboon of a different species acted in precisely the same way. In both of these animals their pitching capacity was demonstrated without any previous practice or instruction, and from these observations it would appear that baboons are natural-born pitchers.

Macacus, the Indian Monkey

Another one of the Old World monkeys, the macacus, shows a different side of the picture. He is more friendly, more gentle, more full of fun, and forever up to some sort of monkeyshines. Many of these monkeys live in India. Mr. Kipling has described them in his famous “Road Song of the Bandar-Log”:

Jabber it quickly and all together! Excellent! Wonderful! Once again! Now we are talking just like men. Let’s pretend we are ... never mind, Brother, thy tail hangs down behind!

These monkeys have their homes throughout the Indo-Malayan regions. They extend northward into China and Japan and eastward into Tibet. The macaques have a stout body and a proportionately large head. There is considerable variation in the tail, which ranges from a long, sweeping, plume-like appendage with a tuft at the tip, as in the lion macaque, to a thick, stubby tail much like that of a dog which has been docked. The pigtail monkey has a curled appendage. One of the macaques of Japan has a mere stump, while the Barbary ape has no tail at all. The macaques are the typical monkeys about which most of the favourite stories concerning the ape kind have had their origin. Their enormous cheek pouches, their facial grimaces, and the motion of their lips make them unusually fascinating to watch. They are extremely noisy, jabbering most of the time. They seem to have an extensive vocabulary of sounds, consisting of shrill calls, grunts, low mutterings, barks, chattering noises, and almost ear-splitting yells, which they emit in moments of rage. They are playful and quarrelsome, and these two phases of their behaviour pass without sharp line one into the other. They never become involved in serious combats because they seldom remain at one thing long enough to be effectual fighters. In their quarters at feeding time they usually make a real pandemonium in their frenzied efforts to stuff their cheek pouches as full as they can. They have absolutely no consideration or courtesy on these occasions. Their table manners are not only rough but actually ruthless, and the most delicious morsels go to the strongest. The weak, the young, and the female obtain what is left or go without. These monkeys are often docile and affectionate. They make the most amusing kind of pets. No animal is more mischievous or more destructive about a home where there is anything within reach to break. Sometimes when they grow up they develop the unpleasant tendency of being too strictly a one-man animal. To protect their owner against an imaginary danger they will often attack strangers or visitors.

Behaviour of Macacus

The head of the macaque is much less dog-shaped than that of the baboon. The eyes are set closely together, and the animal sits on its haunches a good deal of the time holding its head upright, so that the eyes are directed forward. Its posture in sitting is quite human, while its attentive gaze gives the impression that it is watching intelligently all that is going on. Its nose is short and has a fairly good nasal bridge. The lips are thin and the upper one is particularly long. The hands and feet closely resemble human hands, except that the palm is not so broad, the fingers are longer, and the thumb shorter. In its movements the macaque is remarkably deft. It changes from one position to another with surprising swiftness. These monkeys go about in herds, often of considerable size. If captured young the animal is easily trained and quickly learns many amusing tricks. It is full of mischief and curiosity. Macacus monkeys frequently become a nuisance in the neighbourhood of towns where they live in large numbers. When full grown they are sometimes quite ill tempered and often savage even to the extent of attacking the inhabitants without much provocation. For the most part they live in cultivated tracts along the banks of streams. They seem to seek rather than avoid the habitations of man. They manifest little fear for their human neighbours and take a real delight in molesting them by many annoying pranks. Sometimes their attentions are vigorously resented and their human neighbours turn upon them. Their behaviour on such occasions is like that of tantalizing small boys who take an almost idiotic delight in the vain efforts of their pursuers to overtake them, and continue their aggravating antics in order to prolong the excitement of the futile pursuit. If one happens to be captured, a number of them will turn back to take the part of the unfortunate captive. In their native haunts they are constantly on the move. Repose is totally foreign to their daily programme. Scampering, swinging, chattering, screaming, they go among the trees all day long. Either their actions are without design, or else their purpose changes so rapidly and frequently that their behaviour has the appearance of ceaseless motion. When together they are very quarrelsome, constantly nagging or teasing each other, but here, as in all of their activities, the object of their anger, the victim of their jest, is as quickly shifted as their fleeting attention. Having no fear of the water, they are able to swim for long distances and greatly enjoy it. They feed upon spiders and many other insects, besides fruits and berries. As compared with the baboon, they show a greater mental alertness.

Mental Tests

Considerable psychological study has been made of the macaques, particularly concerning their ability to learn and their mentality. Dr. Kinnaman, who has made some of these studies, believes that they have attained a higher level of intelligence than that ascribed to the New World monkeys by Professor Thorndike. He thinks there is some evidence that the macaques have powers of reasoning, although of a low order. Dr. Hobhouse agrees with this view and adds that the macacus monkey seems to be possessed of definite ideas. Professor Yerkes, after a longer and more systematic study with experimental methods better suited to the problem, agrees with Professor Thorndike that the macacus may have a certain number of limited ideas. It is clear to him also that there are extreme differences in the mentality of different species of monkeys. The slow process which they display in the solution of problems is quite surprising, in many instances being actually less rapid than in some of the lower mammals.

One question is certain to arise at this point: How do the Old World monkeys compare in mentality with lemur and tarsius and with the monkeys of the New World? Perhaps the best answer to this question may be obtained by watching the actions of these different animals in their cages at the zoölogical gardens. Looking at a lemur as he jumps about restlessly among the supports of his cage, it is quickly concluded that this animal, not unlike a diminutive fox, is interesting only because of his remarkable agility. Tarsius would probably not be found in most zoölogical gardens because these animals do not survive long in captivity. The marmosets would attract little more attention than the lemurs, not only because of their small size, but also because of their lack of interesting reactions. Howling monkeys, spider monkeys, and woolly monkeys are more interesting because of the remarkable way in which they use their tails like a fifth hand. Their facial expression and their general behaviour, however, are somewhat monotonous.

The Old World monkeys, especially the macaques, hold the attention and create a real interest. Here is to be seen a busy world of jabbering, mischievous, tricky, athletic monkeys whose antics easily rival the best of human clowning. There can be no doubt that these Old World monkeys are on a higher mental plane than those of the New World. The main fault to be found with them is that they never get anything really done, except perhaps filling the pouches in their cheeks just as full as they can. Even the grouchy baboons show some signs of better mental powers than the South American monkeys. They have a thoroughgoing hostility for their human contemporaries which they have never changed, and their powers of organized banditry show a degree of mental capacity that is foreign to the lower monkeys. This capacity we should consider all the more noteworthy because the baboon manifests a distinct tendency to lose some of the benefits derived from living in the trees. It almost seems as though, to a certain extent, it had retrograded. This retrogression appears in the fact that many of the baboon’s characteristics are less ape-like and more dog-like than other Old World monkeys and also because its hands and feet seem to be specialized more in the direction of paws. Yet, in spite of this backsliding on the part of the baboon, the monkeys of the Old World are as a whole eminently more efficient in their actions and capacities than any of the New World monkeys, the lemurs or tarsiers.

Brains of the Old World Monkeys

A question may arise concerning the relation in point of time which the Old World monkeys bear to those of the New World. All of the evidence supplied by fossils indicates that lemurs and tarsiers, as well as the monkeys of South America and Central America, came into existence long before those species which inhabit Africa and Asia. According to most reliable records, the monkeys had their start some time early in the Age of Mammals. It is correct, therefore, to look upon the Old World monkeys as a later and higher stage of development in apedom. This conclusion is borne out when we view the brains of the macaque and the baboon. In this comparison we may be able to detect many signs indicating improvements in the brain; in fact, all doubts may be set at rest concerning the superiority of Old World monkeys.

If we look at the baboon’s brain we are impressed by the fact that it has many more grooves and many more convolutions than the brain of the South American monkey. The convolutions and the grooves of the brain indicate the amount of cell space which the superbrain provides for developing brain power. As between the baboon and the macaque, the difference in this respect somewhat favours the former. This difference is small and may perhaps be discounted by the fact that in macacus the grooves have a slightly more advanced arrangement in consequence of which certain departments of the superbrain show more progressive tendencies than in the baboon. This is particularly true of the department of hearing (temporal lobe) and the department of body and contact senses (parietal lobe). Comparing the groove of Sylvius, whose general angle furnishes such an important standard in rating a brain, there is more of a backward tilting seen in this groove of the macaque than in the baboon. Such an inclination is characteristic of higher races. The central groove appears to be about on a par in both brains, and the ape groove is likewise well developed both in the macaque and the baboon. These three great boundary lines separate the four major lobes of the superbrain. The department of sight in the occipital lobe in macacus has no real advantage over the corresponding area in the baboon. As already noted, the departments of hearing and of body and contact sense are better organized and somewhat more expansive in macacus than in baboon. But when we come to the preëminent part of the superbrain, that portion in which the chief executive function is located, namely, the frontal lobe, the baboon actually seems to have some real advantage. Recalling the ugly disposition and ferocious nature of this animal, we may question why he is superior in this highest part of his brain to the lively and humorous little macaque. It is unfortunate that we have not as yet any good psychological studies of the baboon by which we may compare him with his more nimble associates. Doubtless it is the disagreeable nature and uncompromising aversion which the baboon has for mankind that make it so difficult to estimate him psychologically. Yet there may be something of an enviable consistency in the baboon’s aversion to man that implies a better type of mental power than one might infer from the jabbering, ceaseless activities of the macacus and all of the other bandar-logs. Some explanation of this sort must at present suffice until we are possessed of better standards for psychological comparison.

The two important structures on the base of the brain furnish a definite idea of an animal’s rating. Accepting their evidence, it appears at once that the bridge (pons) bears out our previous observations concerning the powers of the superbrain. This evidence gives the baboon a higher standing in intelligence than the macacus. The value assigned to the bridge in the baboon is .164, while in the macacus it is .150. This contrast gives an interesting corroborative estimate of the superior mental powers of the baboon. From the figures indicating the relative size of the pyramid, it would seem that the macacus is somewhat more richly supplied in his variety of skillful movements than the baboon. The figure in macacus is .147 and baboon .143. While this is not a marked difference, it seems to indicate an advantage probably derived from the more nimble and acrobatic actions of the macacus. This animal has acquired a more highly efficient mastery of tree life as compared with the more sluggish tendencies of baboons, most of which prefer to live upon the ground and go about like other four-legged animals. These contrasts between the Old World monkeys are interesting for what they show in themselves. They give rise to many questions which we would be glad to see answered by more exact and extensive study. The reasons why the baboon or the macacus should be endowed with superior qualities in one particular or another, or why there should be corresponding improvements in the brain, are not clear. There can be no doubt, however, that in the Old World monkeys as a whole both behaviour and brain are in many respects superior to the monkeys of the New World. We cannot fail to discern the special points of this superiority in the brain. It seems impossible to avoid the conclusion that when the Old World monkeys made their appearance they definitely advanced the cause of progressive improvement and that from this progress the brain profited as much as or even more than any other part.

Turning back for a moment to the brains of the New World monkeys and comparing them with those of the Old World group, we will find sufficient evidence to convince us that the chief organ of the body was surely on the way upward, and that the first humble steps taken by the earliest members of monkey kind had been supplemented by further and bold advances.