Chapter 5

We may, indeed, go further than this. We are in a measure justified in saying what this man-ape was like, this creature which had left its early home in the trees and began to walk upright upon the earth, pursuing the larger animals and capturing them for food. It was probably much smaller than existing man, little if any more than four feet in height and not more than half the weight of man. Its body was covered, though not profusely, with hair, the hair of the head being woolly or frizzly in texture, and the face provided with a beard. The complexion was not jet black, like the typical negro, but of a dull brown hue, the hair being somewhat similar in color. The arms were lank and rather long, the back much curved, the chest flat and narrow, the abdomen protruding, the legs rather short and bowed, the walk a waddling motion, somewhat like that of the gibbon. It had small, deep-set eyes, greatly protruding mouth with gaping lips, huge ears, and in general a very ape-like aspect. Our warrant for this description of man's ancestor must be left for a later portion of our work. We shall only say here that it is based on known fact, not on fancy.

VI

THE DEVELOPMENT OF INTELLIGENCE

The full adoption of the erect attitude gave the ancestor of man an immense motor supremacy over the lower animals, for it completely released his fore limbs from duty as organs of support and set them free for new and superior purposes. In all the animal kingdom below man there exists but a single form that emulates him in this possession of a grasping organ which takes no part in walking or in other modes of locomotion. This is the elephant, whose nose and upper lip have developed into an enormous and highly flexible trunk, with delicate grasping powers. The possession of this organ may have had much to do with the intellectual acumen of the elephant. Yet it is far inferior in its powers to the arm and hand of man; while the form, size, and food of the elephant stand in the way of the progress which might have been made by an animal possessed of such an organ in connection with a better suited bodily structure.

For a period of many millions of years the world of vertebrate life continued quadrupedal, or where a variation from this structure took place the fore limbs remained to a large extent organs of locomotion. Finally a true biped appeared. For a period of equal duration the mental progress of animals was exceedingly slow. Then, with almost startling suddenness, a highly intellectual animal appeared. Thus the coming of man indicated, in two directions, an extraordinary deviation from the ordinary course of animal development. Both physically and mentally evolution seemed to take an enormous leap, instead of proceeding by its usual minute steps, and in the advent of man we have a phenomenon remarkable alike in the development of the body and the mind.

So far our attention has been directed to the evolution of the human body, now we must consider that of the human mind. In seeking through the animal kingdom for the probable ancestor of man in his bodily aspect, we were drawn irresistibly to the ape tribe, as the only one that made any near approach to him in structure. In considering the case from the point of view of mental development we find a similar irresistible drawing toward the apes, as the most spontaneously intelligent of the mammalia. While many of the lower animals are capable of being taught, the ape stands nearly alone in the power of thinking for itself, the characteristic of self-education.

Innumerable testimonials could be quoted from observers in evidence of the superior mental powers of the apes. Hartmann says of them that "their intelligence sets them high above other mammals," and Romanes that they "certainly surpass all other animals in the scope of their rational faculty." It is scarcely necessary here to give extended examples of ape intelligence. Hundreds of instances are on record, many of them showing remarkable powers of reasoning for one of the lower animals. The ape, it is true, is not alone in its teachableness. Nearly all the domestic animals can be taught, the dog and the elephant to a considerable degree. And evidences of reasoning out some subject for themselves now and then appear in the domesticated species; but these are rare instances, not frequent acts as in the case of the apes.

The apes, indeed, rarely need teaching. They observe and imitate to an extent far beyond that displayed by any others of the lower animals, and the more remarkable from the fact that in nearly every instance the animals concerned began life in the wild state, and had none of the advantages of hereditary influence possessed by the domesticated dog and horse. Among the most interesting examples of spontaneous acts of intelligence of the ape tribe are those related by Romanes, in his "Animal Intelligence," of the doings of a cebus monkey, which he kept for several months under close observation in his own house. Instead of selecting general examples of ape actions, we may cite some of the doings of this intelligent creature.

The cebus did not wait to be shown how to do things, but was an adept in devising ways to do them himself. He had the monkey love of mischief well developed, and not much that was breakable came whole from his hands. When he could not break an egg cup by dashing it to the ground, he hammered it on the post of a brass bedstead until it was in fragments. In breaking a stick, he would pass it down between a heavy object and the wall, and break it by hanging on its end. In destroying an article of dress, he would begin by carefully pulling out the threads, and afterward tear it to pieces with his teeth. His nuts he broke with a hammer precisely as a man would have done and without being shown its use. Ridicule was not pleasant to him; he strongly resented being laughed at, and would throw anything within reach at his tormentor and with a skill and force not usual with monkeys. Taking the missile in both hands and standing erect, he would extend his long arms behind his back and hurl the article by bringing them forcibly forward.

If any object he wanted was too far away to reach, he would draw it toward him with a stick. Failing in this, he was observed to throw a shawl back over his head, and then fling it forward with all his strength, holding it by two corners. When it fell over the object, he brought this within reach by drawing in the shawl. In his gyrations, the chain by which he was fastened often became twisted around some object. He would now examine it intently, pulling it in opposite ways with his fingers until he had discovered how the turns ran. This done, he would carefully reverse his motions until the chain was quite disentangled.

The most striking act of intelligence told of this creature was his dealings with a hearth-brush which fell into his hands, and of which the handle screwed into the brush. It took him no long time to find out how to unscrew the handle. When this was achieved, he at once began to try and screw it in again. In doing so he showed great ingenuity. At first he put the wrong end of the handle into the hole, and turned it round and round in the right direction for screwing. Finding this would not work, he took it out and tried the other end, always turning in the right direction. It was a difficult feat to perform, as he had to turn the screw with both hands, while the flexible bristles of the brush prevented it from remaining steady. To aid his operations he now held the brush with one foot, while turning with both hands. It was still difficult to make the first turn of the screw, but he worked on with untiring perseverance until he got the thread to catch, and then screwed it in to the end. The remarkable thing was that he never tried to turn the handle in the wrong direction, but always screwed it from left to right, as if he knew that he must reverse the original motion. The feat accomplished, he repeated it, and continued to do so until he could perform it easily. Then he threw the brush aside, apparently taking no more interest in that over which he had worked so persistently. No man could have devoted himself more earnestly to learn some new art, and become more indifferent to it when once learned. These are a few only of the many acts of intelligence observed by Mr. Romanes in the doings of this animal. They will suffice as examples of what we mean by spontaneous intelligence. The cebus did not need to be shown how to do things; it worked them out for itself much as a man would have done, performing acts of an intricacy far beyond any ever observed in other classes of animals in captivity. It may be said further that the displays of spontaneous intelligence shown by dogs, cats, and similar animals have usually been intended in some way for the advantage of the animal; few or none are on record which indicate a mere desire to know without ulterior advantage; no persevering effort, like that with the brush, which is purely an instance of self-instruction.

Examples of intelligence of this advanced character could be cited from observation of monkeys of various species. The anthropoid apes have not been brought to any large extent under observation, but are notable for their intelligence in captivity. It is not easy to observe them in a state of nature, and nearly all we know is that the orang makes itself a nightly bed of branches broken off and carefully laid together, and is said to cover itself in bed with large leaves, if the weather is wet. The chimpanzee has a similar habit, and the gorilla is said to build itself a nest in which the female and the young sleep, the old male resting at the foot of the tree, on guard against their dangerous foe, the leopard.

It is the young animals of these species which are the most social and docile and most approach man in appearance. As they grow older, their specific characters become more marked. Fierce and sullen as is the old gorilla, the young of this species is playful and affectionate in captivity and is given to mischievous tricks. The one that was kept for a time in Berlin showed much good-nature, playfulness, and intelligence, and some degree of monkey mischievousness. It was very cunning in carrying out its plans, particularly in stealing sugar, of which it was very fond.

The chief examples of anthropoid intelligence are told of the chimpanzee, which has been most frequently kept in captivity. It is usually lively and good-tempered and is very teachable. Some of the stories of its intelligence may be apocryphal, as those told by Captain Grandpre of a chimpanzee which performed all the duties of a sailor on board ship, and of one that would heat the oven for a baker and inform him when it was of the right temperature. But there are authenticated stories of chimpanzee intelligence which give it a high standing in this respect among the lower animals.

The emotional nature of the ape is also highly developed. It displays an affection equal to that of the dog, and a sympathy surpassing that of any other animal below man. The feeling displayed by monkeys for others of their kind in pain is of the most affecting nature, and Brehm relates that in the monkeys of certain species kept under confinement by him in Africa, the grief of the females for the loss of their young was so intense as to cause their death. More than once an ardent hunter has seen such examples of tender solicitude among monkeys for the wounded and of grief for the dead as to resolve never to fire at one of the race again.

James Forbes, in his "Oriental Memoirs," relates a striking instance of this kind. One of a shooting party had killed a female monkey in a banian tree, and carried it to his tent. Forty or fifty of the tribe soon gathered around the tent, chattering furiously and threatening an attack, from which they were only diverted by the display of the fowling-piece, whose effects they seemed perfectly to understand. But while the others retreated, the leader of the troop stood his ground, continuing his threatening chatter. Finding this of no avail, he came to the door of the tent, moaning sadly, and by his gestures seeming to beg for the dead body. When it was given, he took it sorrowfully up in his arms and carried it away to the waiting troop. That hunter never shot a monkey again.

This deep feeling for the dead is probably not common among monkeys. The gibbon, for instance, is said to take no notice of the dead. It is, however, highly sympathetic to injured and sick companions, and this feeling seems common to all the apes. No human being could show more tender care of wounded or helpless companions than has often been seen in members of this affectionate tribe of animals.

Without giving further examples of the intelligence and sympathy of the apes, we may say that they possess in a marked degree the mental powers to which man owes so much, viz. observation and imitation. The ape is the most curious of the lower animals--that is, it possesses the faculty of observation in an unusual degree. What we call curiosity in the ape is the basic form of the characteristic which we call attention or observation in man. Its seeming great activity in the ape is what might naturally be expected in an observant animal when removed from its natural habitat to a location where all around it is new and strange. Man under like circumstances is as curious as the ape, while the latter in its native trees probably finds little to excite its special attention. In both man and the ape it needs novelty to excite curiosity.

Again, the ape is imitative in a high degree. This faculty also it does not share with the lower animals, but does with man, imitation being one of the methods by which he has attained his supremacy. Observation, imitation, education, are the three levers in the development of the human intellect. The first two of these the ape possesses in a marked degree. It is susceptible also to the last, being very teachable. Education certainly exists to some extent among the apes in their natural habitat, perhaps to as great an extent as it did in primitive man. In the latter case it is doubtful if there was much that could be called designed education, the young gaining their degree of knowledge by observing and imitating their elders. The same is certainly the case among the apes.

We may reasonably ask what there is in the life and character of the apes to give them this mental superiority over the remaining lower animals. It is certainly not due to the arboreal life and powers of grasp of these animals, for in those respects they resemble the lemurs, which are greatly lacking in intelligence. Whether the monkeys emerged from the lemurs or the two groups developed side by side is a question as yet unsettled; at all events they are closely similar in conditions of existence. Yet while the monkeys are the most intelligent and teachable of animals, the lemurs are among the least intelligent of the mammalia. There is here a marked distinction which is evidently not due to difference of structure or habitat, and must have its origin in some other characteristic, such as difference in life habits.

There is certainly nothing in the diet of the ape to develop intelligence. The frugivorous and herbivorous animals do not need cunning and shrewdness to anything like the extent necessary in carnivorous animals. They do not need to pursue or lie in wait for prey; and they escape from their enemies mainly through strength, speed, concealment, or other physical powers or methods. Escape may occasionally develop mental alertness, but does not usually do so. Certainly if the alert, watchful, suspicious habits of the apes are due to the requisite of avoiding dangerous enemies, we might naturally look for similar habits in the lemurs, which are similarly situated. And if we consider the wide distribution of the apes throughout the tropics of both hemispheres, and their great diversity in species and condition, it seems very unlikely that in all these localities their relations with other animals would be such as to develop the mental alertness which they so generally display. The fact appears to be that, while this may be a cause, it is not a leading cause, of mental development in animals, and that we must seek elsewhere for the origin of animal intelligence.

Research, indeed, leads us to examples of intelligence where we should least expect to find it. Among the mammalia we perceive one marked example in the beavers, the only one in the great class of the rodents, with their nine hundred or more of species. But we must go still lower, to the insects, for the most striking examples, finding them alone in the ants, the bees, and the termites, among the vast multitude of insect forms. Less marked instances appear in the elephants, in some of the birds, and in certain other gregarious animals.

From these examples, and what is elsewhere known of animal intelligence, one broad conclusion may be drawn, that all the strikingly intelligent animals are strongly social in their habits, and that no decided display of intelligence is to be found among solitary species. This conclusion becomes almost a demonstration in the case of the ants and bees. The ants, for instance, comprise hundreds of species, spread over most of the world, mainly social, but occasionally solitary. The social species, while varying greatly in habit, all display powers of intelligence, and these so diversified as to indicate many separate lines of evolution. The solitary ants, on the contrary, manifest no special intelligence, and do not rise above the general insect level. The same may be said of the bees. The hive bee, the most communal in habit, shows the highest traits of intelligent activity. The bees which form smaller groups and the social wasps stand at a lower level, and the solitary bees and wasps sink to the ordinary insect plane. We arrive at like conclusions from observation of the social termites, or white ants, some species of which are remarkable for their intelligent cooeperation and division of duties.

Examples similar in kind may be drawn from the vertebrates. Among the birds there are none more quick-witted than the social crows, none with less display of intelligence than the solitary carnivorous species. Birds are rather gregarious than social. There are few species whose association is above that of mere aggregation in flight. Those more distinctively social usually have special habits which indicate intelligence--as in the often cited instances of their seemingly trying and executing delinquents. Among the carnivorous mammals the social dog or wolf tribe displays the intelligent habit of mutual aid. The horses, oxen, deer, and other gregarious hoofed animals have a degree of division of duties, but their intelligence is of a lower grade than that of the dogs and the elephants. On the whole, it may be affirmed that the social habit is frequently accompanied by instances of special intelligence to which we find no counterpart among the solitary forms, and that the highest manifestations of intelligence in the lower animals are found in those forms which possess communal habits, as the ants, bees, termites, and beavers.

One important characteristic of the communal animals is that they become mentally specialized. They round up their powers, build barriers of habit over which they cannot pass, perform the same acts with such interminable iteration that what began as intellect sinks back into instinct. Each individual has fixed duties and is confined within a limited circle of acts, whose scope it cannot pass, or only to the minutest extent.

The non-communal social animals, on the contrary, are not thus restricted. Their intelligence is of a generalized character, and is capable of developing in new channels. None are tied down to special duties, each possesses the full powers of all, and they are thus more open to a continued growth of the intellect than the communal forms. To this class belongs the ape. Its intelligence is general, not special; broadly capable of development, not narrowed and bound in by the limitation of certain fixed and special duties.

The suggestions above offered point to three grades of community among animals, which may be designated the communal, the social, and the solitary. Among these there are, of course, many stages of transition from one to the other. The specially communal, including the ants, bees, termites, and beavers, are those in which there is almost a total loss of individuality, each member working for the good of the community as a unit, not for its personal advantage. The result consists in organized industries, division and specialization of duties, a common home, food stock, etc. At a lower level in animal life, that of the hydroid polyps, communism has become so complete that the community has grown into an actual individual, the members not being free, but acting as organs of an aggregate mass, in which each performs some special duty for the good of the community.

The social animals differ from the communal in that the individuality of the members is fully preserved. There is some measure of work for the group, some degree of mutual aid, some evidence of leadership and subordination, but these are confined to a few exigencies of life, while in most of the details of existence each member of the group acts for itself. The solitary animals are those which do not form groups larger than that of the family, and into whose life the principle of mutual aid, outside the immediate family relations, does not enter. Each acts for itself alone, and intercourse between the individuals of the species is greatly restricted.

The advantages of social habits among animals are evident. There is excellent reason to believe that all animals, and especially such advanced forms as the vertebrates and the higher arthropods, have some power of mental development, some facility in devising new methods of action to meet new situations. Though their reasoning power may be small, it is not quite lacking, and many examples of the exercise of the faculty of thought could be cited if necessary.

What we are here concerned with, is the final result of such exercises of individual thought powers. In the case of the solitary forms, such new conceptions die with the individual. Though they may exert an influence on the development of the nervous system, and aid in the hereditary transmission of more active brain powers, they are lost as special ideas, fail to be taken up and repeated by other members of the species. This is not the case with the social animals. Each of these has some faculty of observation and some tendency to imitation, and useful steps of advance made by individuals are likely to be observed and retained as general habits of the community. Anything of importance that is gained may be preserved by educative influences. The facility of mental communication between these creatures is perhaps much greater than is generally supposed, and acts of importance which are not directly observed might in many cases be transmitted through repetition for the benefit of the group. We know this to be the main agency in human progress. New ideas are of rare occurrence with man. Ideas of permanent value do not occur to one per cent., perhaps not to one hundredth of one per cent., of civilized mankind, yet few of such ideas are lost, and that which has proved of advantage to an individual soon becomes the common possession of a community.