Pleasant Ways in Science

by Richard A. Proctor

It may be well, in the first place, to point out that the terms “ape,” “baboon,” and “monkey” are no longer used as they were by the older naturalists. Formerly the term “ape” was limited to tailless simians having no cheek-pouches, and the same number of teeth as man; the term “baboon” to short-tailed simians with dog-shaped heads; and the term “monkey,” unless used generically, to the long-tailed species. This was the usage suggested by Ray, and adopted systematically thirty or forty years ago. But it is no longer followed, though no uniform classification has been substituted for the old arrangement. Thus Mivart divides the apes into two classes—calling the first the Simiadæ, or Old World apes; and the second the Cebidæ, or New World apes. He subdivides the Simiadæ into (1) the Siminæ, including the gorilla, chimpanzee, orang, and gibbon; (2) the Semnopithecinæ; and (3) the Cynopithecinæ; neither of which subdivisions will occupy much of our attention here, save as respects the third subdivision of the Cynopithecinæ, viz., the Cynocephali, which includes the baboons. The other great division, the Cebidæ, or New World apes, are for the most part very unlike the Old World apes. None of them approach the gorilla or orang-outang in size; most of them are long-tailed; and the number and arrangement of the teeth is different. The feature, however, which most naturalists have selected as the characteristic distinction between the apes of the Old World and of the New World is the position of the nostrils. The former are called Catarhine, a word signifying that the nostrils are directed downwards; the latter are called Platyrhine, or broad-nosed. The nostrils of all the Old World apes are separated by a narrow cartilaginous plate or septum, whereas the septum of the New World apes is broad. After the apes come, according to Mivart’s classification, the half-apes or lemuroids.

I ought, perhaps, to have mentioned that Mivart, in describing the lemuroids as the second sub-order of a great order of animals, the Primates, speaks of a man as (zoologically speaking) belonging to the first sub-order. So that, in point of fact, the two sub-orders are the Anthropoids, including the Anthropos (man) and the Lemuroids, including the lemur.

The classification here indicated will serve our present purpose very well. But the reader is reminded that, as already mentioned, naturalists do not adopt at present any uniform system of classification. Moreover, the term Simiadæ is usually employed—and will be employed here—to represent the entire simian race, i.e., both the Simiadæ and the Cebidæ of Mivart’s classification.

And now, turning to the Anthropoid apes, we find ourselves at the outset confronted by the question, Which of the four apes, the gorilla, the orang-outang, the chimpanzee, or the gibbon, is to be regarded as nearest to man in intelligence? So far as bodily configuration is concerned, our opinion would vary according to the particular feature which we selected for consideration. But it will probably be admitted that intelligence should be the characteristic by which our opinions should be guided.

The gibbon may be dismissed at once, though, as will presently appear, there are some features in which this ape resembles man more closely than either the gorilla, the orang-outang, or the chimpanzee.

The gorilla must, I fear, be summarily ejected from the position of honour to which he has been raised by many naturalists. Though the gorilla is a much larger animal than the chimpanzee, his brain barely equals the chimpanzee’s in mass. It is also less fully developed in front. In fact Gratiolet asserts that of all the broad-chested apes, the gorilla is—so far as brain character is concerned—the lowest and most degraded. He regards the gorilla’s brain as only a more advanced form of that of the brutal baboons, while the orang’s brain is the culminating form of the gibbon type, and the chimpanzee’s the culminating form of the macaque type. This does not dispose of the difficulty very satisfactorily, however, because it remains to be shown whether the gibbon type and the macaque type are superior as types to the baboon types. But it may suffice to remark that the baboons are all brutal and ferocious, whereas the gibbons are comparatively gentle animals, and the macaques docile and even playful. It may be questioned whether brutality and ferocity should be regarded as necessarily removing the gorilla further from man; because it is certain that the races of man which approach nearest to the anthropoid apes, with which races the comparison should assuredly be made, are characterized by these very qualities, brutality and ferocity. Intelligence must be otherwise gauged. Probably the average proportion of the brain’s weight to that of the entire body, and the complexity of the structure of the brain, would afford the best means of deciding the question. But, unfortunately, we have very unsatisfactory evidence on these points. The naturalists who have based opinions on such evidence as has been obtained, seem to overlook the poverty of the evidence. Knowing as we do how greatly the human brain varies in size and complexity, not only in different races, but in different individuals of the same race, it appears unsatisfactory in the extreme to regard the average of the brains of each simian species hitherto examined as presenting the true average cerebral capacity for each species.

Still it seems tolerably clear that the choice as to the race of apes which must be regarded as first in intelligence, and therefore as on the whole the most manlike, rests between the orang-outang and the chimpanzee. “In the world of science, as in that of politics,” said Professor Rolleston in 1862, “France and England have occasionally differed as to their choice between rival candidates for royalty. If either hereditary claims or personal merits affect at all the right of succession, beyond a question the gorilla is but a pretender, and one or other of the two (other) candidates the true prince. There is a graceful as well as an ungraceful way of withdrawing from a false position, and the British public will adopt the graceful course by accepting forthwith and henceforth the French candidate”—the orang-outang. If this were intended as prophecy, it has not been fulfilled by the event, for the gorilla is still regarded by most British naturalists as the ape which comes on the whole nearest to man; but probably, in saying “the British public will adopt the graceful course” in accepting the orang-outang as “the king of the Simiadæ,” Professor Rolleston meant only that that course would be graceful if adopted.

Before the discovery of the gorilla, the chimpanzee was usually regarded as next to man in the scale of the animal creation. It was Cuvier who first maintained the claim of the orang-outang to this position. Cuvier’s opinion was based on the greater development of the orang-outang’s brain, and the height of its forehead. But these marks of superiority belong to the orang only when young. The adult orang seems to be inferior, or at least not superior, to the chimpanzee as respects cerebral formation, and in other respects seems less to resemble man. The proportions of his body, his long arms, high shoulders, deformed neck, and imperfect ears are opposed to its claims to be regarded as manlike. In all these respects, save one, the chimpanzee seems to be greatly its superior. (The ear of the chimpanzee is large, and not placed as with us: that of the gorilla is much more like man’s.)

As to the intelligence exhibited in the conduct of the chimpanzee and orang-outang, various opinions may be formed according to the various circumstances under which the animals are observed. The following has been quoted in evidence of the superiority of the chimpanzee in this respect:—“About fifty years ago, a young chimpanzee and an orang-outang of about the same age were exhibited together at the Egyptian Hall. The chimpanzee, though in a declining state of health, and rendered peevish and irritable by bodily suffering, exhibited much superior marks of intelligence to his companion; he was active, quick, and observant of everything that passed around him; no new visitor entered the apartment in which he was kept, and no one left it, without attracting his attention. The orang-outang, on the contrary, exhibited a melancholy and a disregard of passing occurrences almost amounting to apathy; and though in the enjoyment of better health, was evidently much inferior to his companion in quickness and observation. On one occasion, when the animals were dining on potatoes and boiled chicken, and surrounded as usual with a large party of visitors, the orang-outang allowed her plate to be taken without exhibiting the least apparent concern. Not so, however, the chimpanzee. We took advantage of an opportunity when his head was turned (to observe a person coming in) to secrete his plate also. For a few seconds he looked round to see what had become of it, but, not finding it, began to pout and fret exactly like a spoiled child, and perceiving a young lady, who happened to be standing near him, laughing, perhaps suspecting her to be the delinquent, he flew at her in the greatest rage, and would probably have bitten her had she not got beyond his reach. Upon having his plate restored, he took care to prevent the repetition of the joke by holding it firmly with one hand, while he fed himself with the other.”

This story can hardly be regarded as deciding the question in favour of the chimpanzee. Many animals, admittedly far inferior to the lowest order of monkeys in intelligence, show watchfulness over their food, and as much ill-temper when deprived of it, and as much anxiety to recover it, as this chimpanzee did. A hundred cases in point might readily be cited.[36]