THE CHIMPANZEE
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 about half-way across the continent. His range can be defined
with more precision, but its exact limits are not quite certain. Its
boundary on the north is defined by the Kameroon valley, slightly
curving to the north, but its extent eastward is not well known. He
does not appear to be found anywhere north of this 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, its
boundary starts from the coast, at a point near the fifth parallel,
curves northward, crossing the Congo near Stanley Pool, pursues a
north-east course, to the centre of the Congo State, again curves
southward, across the Upper Congo, towards the north end of Lake
Tanganyika. Its limits appear to conform more to isothermal lines, than
to the rigid lines of geometry.
Specimens are sometimes secured by collectors beyond the limits
mentioned, but so far as I can ascertain they appear to have been
captured within these limits. There are numerous centres of population.
This ape is not strictly confined to any definite topography, but
occupies the upland forests or the low basin lands.
In one section he is known to the natives by one name, and in another
by quite a different one. The name _chimpanzee_ is of native origin.
In the Fiot 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 Fiot word _tyi_, which white men erroneously
pronounce like "chee." It means "small," and is found in many of the
native compounds. The latter syllable is from _mpâ_, a bushman, hence
the word literally means, in the Fiot tongue, "a small bushman."
Among other tribes the common name of the ape is _ntyigo_. The two
names appear to come from the same ultimate source. The latter is
derived from the Mpongwe word _ntyia_, blood, hence breed, and the word
_iga_, the forest, and literally means the "breed of the forest." The
same idea is involved in the two names, and both convey the oblique
idea that the animal is something more like man than other animals are.
There are two distinct types of this ape, and 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, between
the second and fifth parallels, and west of the Congo. Both kinds are
found within these limits, but the variety which is confined to that
region is called, by the tribes that know the ape, the _kulu-kamba_, in
contradistinction to the other kind, known as _ntyigo_. This name is
derived from _kulu_, the onomotope 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 points the common variety differs from the _kulu-kamba_ in
a degree that would indicate that they belong to distinct species,
but the skulls and skeletons are so nearly the same, that no one can
identify them with certainty. 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 colour. He has a thin coat of short black hair, which is
often described as brown, but that effect is due to the colour of his
skin blending 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 him a dingy grey colour. The change is due to the same causes
that produce grey hairs on the human body. But there is one point in
which they differ. The entire hair of the human becomes white with age,
while only the end of it does so in the chimpanzee. In the human, one
hair becomes white, while another retains its natural colour, 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 colour, which is due to the want of vascular action
to supply the colour pigment, and the same effect is often seen in
preserved specimens, for the same reason that the hair of an Egyptian
mummy is brown, while in life it was 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 chin.
I have examined about sixty living specimens and I have never found
any other colour among them only from the cause mentioned. The normal
colour of both sexes is the same.
The _kulu_, as a rule, has but little hair on the top of its head, but
that on the back of it and on the neck is much longer than elsewhere on
the body, and longer on them than on other apes.
Much stress is laid by some writers on the bald head of one ape and the
parted hair on that 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 summit of its 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 the
same. Some of them have the hair growing almost down to the eyebrows,
and each hair appears to diverge from a common centre like the radii
of a sphere: another of the same species will have the hair parted in
the middle as neatly as if it had been combed, while 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 them
it signifies nothing. It may be remarked that as a whole the _kulu_ is
inclined to have little hair upon the crown of the head.
Between the two species there is a close alliance, but the males differ
more than the females. This is especially true in the structure of
certain organs.
The face in youth is quite free from hairs, but in the adult state
there is, in both sexes, a slight tendency to grow a light down over
the cheeks.
The colour of the skin is not uniform in all parts of the body,
especially on the face. Some specimens have patches of dark colour set
in a lighter ground. Sometimes certain parts of the face will be dark,
and other parts light. I have seen one specimen quite freckled.
It is said by some that the skin is light in colour when young, and
becomes darker with age, but such is not the case. It is true that
the skin darkens a few shades as the cuticle hardens, but there is no
transition from one colour to another, and this slight change of shade
is only on the exposed parts.
The _kulu_ has a short, round face, very 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 a heavy suit of hair on the body. It is
coarser than that of the _ntyigo_, longer, and inclined to wave, giving
it a fluffy aspect. The colour is jet black, except a small tuft of
white about the base of the spine.
The skin varies in colour less than in the _ntyigo_, and the darker
shades seldom appear. The eyes are a shade darker, and in both
species the parts of the eye which are white in man are brown in the
chimpanzee, gradually shading 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 apes differ is in the scope and
quality of voice. The _kulu_ makes a greater range of vocal sounds than
the other. Some of them are soft and musical, while those uttered by
the _ntyigo_ are fewer in number and more harsh in quality. One of them
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 this instinct. There are many traits in
which they differ, but human beings, of the same family, 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 the
same, except a slight structural variation in the genital organs of
the males, and the degree of mobility in certain facial muscles. The
character of their food, and the mode of eating it, are the same in
each. In captivity they appear to regard each other as one of their own
kind, but whether they mate or not remains to be learned.
Such is the sum of the likenesses and differences between the two
extreme types of this genus; but 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 marked
varieties of a common species. This doubt is further emphasised by the
fact that all the way between these two extremes are many gradations of
intermediate types, so that it is next to impossible to say where one
ends and the other 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 plebeian of one race, or the
nobility and yeomanry of one tribe. They are like different phases of
the same moon. The _kulu-kamba_ is simply a high order of chimpanzee.
[Illustration: IN THE JUNGLE]
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 favour 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 status.
Whether they be 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 in general. There are many incidents to be related elsewhere,
which apply to individuals of the special kinds mentioned, but for the
present the term chimpanzee is meant to include the whole group, except
where it may be otherwise specified.