CHAPTER X
The Chimpanzee—The Name—Two Species—The Kulu-Kamba Distribution—Color and Complexion
Next to man the chimpanzee occupies the highest plane in the scale of nature. His mental and social traits, together with his physical type, assign him to this place.
In his distribution he is confined to equatorial Africa. His habitat, roughly outlined, is from the fourth parallel north of the equator to the fifth parallel south of it, along the west coast, and extends eastward a little more than halfway across the continent. His range cannot be defined with precision, for its exact limits are not yet known. Its boundary on the north is defined by the Cameroon valley, slightly curving towards the north; but its extent eastward is a matter of some doubt. He does not appear to be found anywhere north of that river, and it is quite certain that the few specimens attributed to the north coast of the Gulf of Guinea do not belong to that territory. On the south the boundary of his habitat starts from the coast, at a point near the fifth parallel, curves slightly northward, crosses the Congo near Stanley Pool, pursues a northeasterly course to about the middle of the Congo State, and again curves southward across the Upper Congo, not far from the north end of Lake Tanganyika. Its limits appear to conform more to isothermal lines than to the rigid lines of geography. Specimens are sometimes secured by collectors beyond these limits, but, so far as I have been able to ascertain, they have been captured within the territory thus bounded. There are several centers of population. This ape is not strictly confined to any definite topography, but occupies alike the upland forests or the low basin lands.
In one section he is known to the natives by one name, and in another by a name entirely different. The name chimpanzee is of native origin. In the Fiote tongue the name of the ape is chimpan, which is a slight corruption of the true name. It is properly a compound word. The first syllable is from the Fiote word tyi, which white men erroneously pronounce like “chee.” It means “small,” or inferior, and it is found in many of the native compounds. The last syllable is from mpa, a bushman; hence the word literally means, in the Fiote tongue, “a small bushman,” or inferior race. The name really implies the idea of a lower order of human being. Among other tribes a common name of the ape is ntyigo. The latter is derived from the Mpongwe word ntyia, blood, race, or breed, and the word iga, the forest. It literally means the “breed of the forest.” The same idea of its being a low type of humanity is involved in the two names. Both convey the oblique suggestion that the animal is more nearly allied to man than other animals are.
There are two distinct types of this ape. They are now regarded as two species. One of them is distributed throughout the entire habitat described, while the other is only known south of the equator and between the second and fifth parallels north of the Congo and west of Stanley Pool. Both kinds are found within this district, but the variety which is confined to that region is called, by the tribes that know the ape, the kulu-kamba, in contradistinction from the other kind known as ntyigo. This name is derived from kulu, the onomatope of the sound made by the animal and the native verb, kamba, to speak; hence the name literally means “the thing that speaks kulu.”
In certain respects the common variety differs from the kulu-kamba in a degree that would indicate that they belong to distinct species; but the skulls and the skeletons are so nearly alike that no one can identify them from the skeletons alone. In life, however, it is not difficult to distinguish them. The ntyigo has a longer face and more prominent nose than the kulu. His complexion is of all shades of brown, from a light tan to a dark, dingy, mummy color. He has a thin coat of short, black hair, which is often erroneously described as brown; but that effect is due to the blending of the color of his skin with that of his suit. In early life his hair is quite black, but in advanced age the ends are tipped with a dull white, giving them a dingy gray color. The change is due to the same causes that produce gray hairs on the human body. But there is one point in which they greatly differ. The entire hair of the human becomes white with age, while only the outer end of it does so in the chimpanzee. In the human one hair becomes white, while others retain their natural color; but in this ape all the hairs appear to undergo the same change. In very aged specimens the outer part of the hair often assumes a dirty, brownish color. This is due to the want of vascular action to supply the color pigment. The same effect is often seen in preserved specimens, for the same reason that the hair of an Egyptian mummy is brown, though in life it had been, doubtless, a jet black. In this ape the hair is uniformly black, except the small tuft of white at the base of the spinal column and a few white hairs on the lower lip and the chin. I have examined about sixty living specimens, and I have never found any other color among them, except from the cause mentioned. The normal color of both sexes is the same. The kulu has, as a rule, but little hair on the top of the head; but that on the back of it and on the neck is much longer than elsewhere on the body, and on these parts it is longer than that on other apes.
Much stress is laid by some writers on the bald head of one ape and the parted hair on the head of another. These features cannot be relied upon as having any specific meaning, unless there are as many species as there are apes. Sometimes a specimen has no hair on the crown of the head, while another differs from it in this respect alone by having a suit of hair more or less dense; and yet in every other respect they are alike. Some of them have their hair growing almost down to the eyebrows, and all hairs appear to diverge from a common center, like the radii of a sphere; another of the same species may have the hair parted in the middle as neatly as if it had been combed; another may have it in wild disorder. The same thing is noticed in certain monkeys, and it is equally true of the human being. As a factor in classifying, it signifies nothing. It may be remarked that the kulu is inclined to have but little hair upon the crown of the head.
Between the two species there is a close alliance. The males differ more than the females. This is especially true in the structure of certain organs. The face of the young ntyigo is free from hairs, but in the adult state there is in both sexes a tendency to the growth of a light down upon the cheeks. The color of the skin is not uniform in all parts of the body. This is especially true of the face. Some specimens have patches of dark color set in a lighter ground. Sometimes certain parts of the face are dark and other parts light. I have seen one specimen quite freckled. It is said by some that the skin is light in color when young, and becomes darker with age; but I find no reason to believe that such is the case. It is true that the skin darkens a few shades as the cuticle hardens, but there is no transition from one color to another, and this slight change of shade is chiefly on the exposed parts.
The kulu has a short, round face, much like that of a human. In early life it is quite free from hairs, but, like the other, a slight down appears with age. He has on his body a heavy suit of black hair. It is coarser and longer than that of the ntyigo. It is also inclined to wave, thus having a fluffy aspect. The color is jet black, except a small tuft of white about the base of the spine. I have seen two in which this tuft was perfectly black. The skin varies in color less than in the ntyigo, and the darker shades are seldom found. The eyes are a shade darker, and in both species the parts of the eye which are white in man are brown in them. But this gradually shades off into a yellow near the base of the optic nerve. As a rule, the kulu has a clear, open visage, with a kindly expression. It is confiding and affectionate to a degree beyond any other animal. It is more intelligent than its confrère, and displays the faculty of reason almost like a human being.
One important point in which these two types of ape differ is in the scope and quality of their voices. The kulu makes a greater range of vocal sounds. Some of them are soft and musical; but those uttered by the ntyigo are fewer in number and harsher in quality. One of these sounds resembles the bark of a dog, and another is a sharp, screaming sound. The kulu evinces a certain sense of gratitude, while the ntyigo appears to be almost devoid of that sentiment. There are many traits in which they differ, but human beings, even within the same family circle, also differ in these qualities. The points in which they coincide are many, and, after a brief review of them, we may consider the question of making two species of them or assigning them to the same.
The skeletons—as we have noted—are the same in form, size, and proportion. Their muscular, nervous, and veinous systems are for the most part the same. The character of their food and the mode of eating are the same in each. In captivity they appear to regard each other as one of their own kind; but whether they inter-cross or not remains to be learned.
Such is the sum of the likenesses and the differences between the two extreme types of this genus. With so many points in common, and so few in which they differ, it is a matter of serious doubt whether they can be said to constitute two distinct species or only two varieties of a common species. This doubt is further emphasized by the fact that all the way between these two extremes are gradations of intermediate types, so that it is next to impossible to say where one ends and another begins.
In view of all these facts, I believe them to be two well-defined varieties of the same species. They are the white man and the negro of a common stock. They are the patrician and the plebeian of one race, or the nobility and the yeomanry of one tribe. They are like different phases of the same moon. The kulu-kamba is simply a high order of chimpanzee. It is quite true that two varieties of one species usually have the same vocal characteristics, and this appears to be the strongest point in favor of assigning them to separate species, but it is not impossible that even this may be waived. Leaving this question for others to decide as they find the evidence to sustain them, we shall for the present regard them as one kind, and consider their physical, social, and mental characteristics.
Whether they are all of one species, or divided into many, the same habits, traits, and modes of life prevail throughout the entire group, so that one description will apply to all, so far as we have to deal with them as a whole. Elsewhere will be related certain incidents which apply to individuals of the two kinds mentioned; but in treating of them collectively the term chimpanzee is meant to include the whole group, except where it is otherwise specified.