PHYSICAL, SOCIAL, AND MENTAL QUALITIES
Physically, the chimpanzee, as we have seen, closely resembles man,
but there are certain points that have not been mentioned in which he
differs from him, also from other apes. We may here take note of a few
of those points.
The model and structure of the ear of this ape are somewhat the same
as those of man, but the organ is larger in size, and thinner in
proportion. It is very sensitive to sound, but dull to the touch,
indicating that the surface is not well provided with nerves. He cannot
move it as other animals move theirs by the use of the muscles at its
base, but, like the human ear, it is quite fixed and helpless in this
respect.
The hand of the chimpanzee is long and narrow. The finger bones are
longer, in proportion to their size, than those of the human hand, and
slightly more curved in the plane of the digits. One thing peculiar in
the hand of the chimpanzee, is that the tendons inside of the hand,
which are called the flexors, and designed to close the fingers, are
shorter than the line of the bones, and on this account the fingers
of the ape are always held in a curve, so that he cannot possibly
straighten them into a line. This is probably due to the habit of
climbing in which he indulges to a great extent; also to the practice
of hanging by the hands. In making his way through the bush, he often
swings from bough to bough by the arms alone, and sometimes suspends
himself by one arm, while he uses the other to pluck and eat fruit.
This characteristic is transmitted to the young, and is found in the
first stages of infancy. The thumb is not truly opposable, but is
inclined to close towards the palm of the hand. It is of little use to
him. His nails are thick, dark in colour, and not so flat as those of
man.
Instead of having the great toe in line with the others, it projects
at an angle from the side of the foot, something after the manner of
the human thumb. The foot itself is flexible, and has great prehensile
power. In climbing, and in many other ways, it is used as a hand. The
tendons in the sole of the foot are equal in length to the line of the
bones, and the digits of the foot can be straightened, but both members
are inclined to curve into an arch in the line of the first and second
digits.
His habit of walking is peculiar. The greater part of the weight is
borne upon the legs. The sole of the foot is placed almost flat on the
ground, but the pressure is greatest along the outer edge of it, in the
line of the last digit. This is easily noticed where he walks through
plastic ground. In the act of walking he always uses the hands, but
does not place the palm on the ground; he uses the backs of the fingers
instead, sometimes only the first joints are placed on the ground,
resting on the nails; at other times the first and second joints are
used, while at others the backs of all the fingers from the knuckles to
the nails serve as a base for the arm. The integument on these parts is
not callous, like that of the palm; the colour pigment is distributed
the same as on other exposed parts of the body, which shows that the
weight of the body is not borne on the fore limbs, as it is in the
case of a true quadruped, but indicates that the hand is only used to
balance the body and shift the weight from foot to foot, while in the
act of walking. The weight is not equally distributed between the hands
and the feet.
His waddling gait is caused by his short legs, stooping habit and heavy
body. All bipeds with stout bodies and short legs are predisposed to a
waddling motion, which is due to the wide angle between the weight and
the changing centre of gravity.
The chimpanzee is neither a true quadruped, nor a true biped, but
combines the habits of both. It appears to be a transition state from
the former to the latter, and a vestige of this habit is still to be
found in man, whose arms alternate in motion with his legs in the act
of walking, which suggests the idea that he may, at some time, have had
a similar habit of locomotion. Such a fact does not show that he was
ever an ape, but it does point to the belief that he has once occupied
a like horizon in nature to that now occupied by the ape, and that
having emerged from it, he still retains traces of the habit.
This peculiarity is still more easily observed in children than in
adults. In early infancy all children are inclined to be bow-legged,
and in their first efforts at walking, invariably press most of their
weight on the outer edge of the foot, and curve the toes inward, as
if to grasp the surface on which the foot is placed. The instinct to
prehension cannot be mistaken; it differs in degree in different races,
and is vastly more pronounced in negro than in white infants.
There is another peculiar feature in the walk of the chimpanzee. The
motion of the arms and legs do not alternate with the same degree of
regularity that they do in man or quadrupeds. This ape uses his arms
more like crutches. They are moved forward, not quite, but almost at
the same instant, and the motion of the legs is not at equal intervals.
To be more explicit: the hands are placed almost opposite each other;
the right foot is advanced about three times its length; the left foot
placed about one length in front of it; the arms are again moved; the
right foot again advanced about three lengths forward of the left; and
the left again brought about one length in front of it. The same animal
does not always use the same foot to make the long stride. It will be
seen by this that each foot moves through the same space, and that in
a line, the tracks of either foot are the same distance apart, but the
distance from the track of the right foot to that of the left is about
three times as great as the distance from the track of the left foot to
that of the right; or the reverse may be the case. The distance from
the track of either foot to the succeeding track of the other, is never
the same between the right and left tracks, except where the animal is
walking at great leisure.
There is, perhaps, no animal more awkward than the chimpanzee, when
he attempts to run. He sometimes swings his body with such force
between his arms as to lose his balance, and falls backward on the
ground. I have often seen him do this, and when he would right himself
again, would be half his length farther backward than forward of his
starting-point.
The chimpanzee is doubtless a better climber than the gorilla. He finds
much of his food in trees, but is not arboreal in habit in the proper
sense of that term. To be arboreal, the animal must sleep in trees or
on a perch, but the chimpanzee cannot do so. He sleeps the same as a
human being does. He lies down on the back or side, and, as a rule,
uses his arms for a pillow. I do not believe it possible for him to
sleep on a perch. He may sometimes doze in that way, but the grasp of
his foot is only brought into use when he is conscious of it. I have
often known Moses to climb down from the trees and lie upon the ground
to take a nap. I never even saw him so much as doze in any other
position.
I may here call attention to one fact concerning the arboreal habit.
There appears to be a rule to which this habit conforms. Among apes
and monkeys the habit is in keeping with the size of the animal. The
largest monkeys, as a rule, are only found among the lowest trees, and
the smaller monkeys among the taller trees. It is a rare thing ever
to see a large monkey in the top of a tall tree. He may venture there
for food or to make his escape, but it is not his proper element. This
same rule appears to hold good among the apes themselves. The gibbon
has this habit in a more pronounced degree than any other true ape.
The orang appears to be next; the chimpanzee then comes in for a third
place, and the gorilla last. It must not be understood that all of
these apes do not frequently climb, even to the tops of the highest
trees; but that is not their normal mode of life any more than the top
of a mast is the proper place on a ship for a sailor.
The chimpanzee is nomadic in habit, and, like the gorilla, seldom or
never passes two nights in the same spot. As to his building huts or
nests in trees or elsewhere, I am not prepared to believe that he ever
does so. I hunted in vain, for months, and made diligent inquiry in
several tribes, but failed to find a specimen of any kind of shelter
built by an ape. I do not assert that it is absolutely untrue, but I
have never been able to obtain any evidence, except the statement of
the natives that it was true. On the contrary, certain facts point to
the opposite belief. If the ape built him a permanent home the natives
would soon discover it, and there would be no difficulty in having
it pointed out. If he built a new one every night, however rude and
primitive it might be there would be so many of them in the forest that
there would be no difficulty in finding them. The nomadic habit plainly
shows that he does not build the former kind, and the utter absence of
them shows that he does not build the latter kind, and the whole story
appears to be without foundation.
In addition to these facts, one thing to be noticed is that few or
none of the mammals of the tropics ever build any kind of a home. Even
the animals that have the habit of burrowing in other climates, do not
appear to do so in the tropics. This is due, no doubt, to the warm
climate, in which they are not in need of shelter. Of course birds, and
other oviperous animals, build nests, as they do elsewhere.
The longevity of these apes is largely a matter of conjecture, but
from a cursory study of their dentition and other factors of their
development, it appears that the male reaches the adult stage at an age
ranging from nine to eleven years, while the female matures at six or
seven. These appear to be the periods at which they pass from the state
of adolescence. Some of them live to be perhaps forty years of age, or
upwards, but the average of life is doubtless not more than twenty-two
or twenty-three years. The average of life is more uniform with them
than with man. These figures are not mere guesswork, but are deduced
from reliable data.
The period of gestation in both these apes is a matter that cannot
be stated with certainty. Some of the natives say that it is nine
months, while others believe that it is seven months or less, and there
are some facts to support both of these claims, but nothing quite
conclusive. The sum of the evidence that I could find rather pointed to
a term of three months or thereabouts as the true period. During the
months of February and March the male gorillas are vociferous in their
screaming, the young adults separate from the families, and some other
things indicate that this is the season of pairing and breeding. Such
may not be the case, but the inference is well-founded. It is quite
certain that the season of bearing the young is from the beginning
of May to the end of June. It is about this time that the dry season
begins and continues for four months. It would appear that nature has
selected this period of the year because it is more favourable for
rearing the young. During this season food is more abundant and can be
secured with less effort. The lowlands are drier, and this enables the
mother to retire to the dense jungle with her young, where she is less
exposed to danger than she would be in the more open forest.
It is not certain whether the periods are the same with both apes or
not, and native reports differ on this point, but it is probable that
they are the same.
From a social point of view, the chimpanzee appears to be of a little
higher caste than other animals. In his marital ideas he is polygamous,
but is, in a certain degree, loyal to his family. The paternal instinct
is a trifle more refined in him than in most other animals. He seems
to appreciate the relationship of parent and child more, and retain
it longer than others do. Most male animals discard their young, and
become estranged to them at a very early age; but the chimpanzee keeps
his children with him until they are old enough to go away and rear a
family of their own.
The family of the chimpanzee frequently consists of three or four
wives and ten or twelve children, with one adult male; but there are
cases known in which two or three elderly males have been seen in the
same family, but they appear to have their own wives and children.
In such an event, however, there seems to be one who is supreme.
This fact suggests the idea that among them a form of patriarchal
government prevails. The wives and children do not appear to question
the authority of the patriarch, or to rebel against it. The male parent
often plays with his children, and appears to be fond of them.
[Illustration: A STROLL IN THE JUNGLE]
There is one universal error that I desire here to correct. It is the
common idea that animals are so strongly possessed of the parental
instinct that they nobly sacrifice their own lives in defence of
their young. I do not wish to dispel any belief that tends to dignify
or ennoble animals, for I am their special friend and champion; but
truth demands that we qualify this statement. It is quite true that
many have lost their lives in such acts of defence, but it was not a
voluntary sacrifice. It was not alone in the defence of their young,
but in many cases it was in self-defence. In others, it was from a lack
of judgment. These apes have often been frightened away from their
young, and the latter captured while the parents were fleeing from
the scene. This may have been the result of sagacity rather than of
depravity, but the parental instinct in both sexes, in many instances,
has failed to restrain them from flight. If it be a foe that appears
to come within the measure of their own power, they will certainly
defend their young, and this sometimes results in the loss of their own
lives; but if it be one of such formidable aspect as to appear quite
invincible, the parents leave the young to their fate. This is true of
many other animals, including man.
I have no desire to detract from the heroic quality of this instinct,
or to dim the glory it sheds upon noble deeds ascribed to it; but the
fact that a parent incurs the risk of its own life in the defence of
its young, is not a true test of its strength or quality. It is only
in the few isolated cases of a voluntary sacrifice of the parent,
foreknowing the result, that it can be said the act was due to the
instinct. In most cases it is under the belief in its ability to
rescue the one in danger, but the parent is not wholly aware of its own
danger.
I doubt if any animal except man ever deliberately offered its own life
as a ransom for that of another, and such instances in human history
are so rare as to immortalise the actor.
To whatever extent the instinct may be found, it is much stronger in
the female than in the male, and it appears to be stronger in domestic
animals than in wild ones. To what extent this is due to their contact
with man, it is difficult to say. The germ may be inherent, but it
certainly yields to culture.
The fact of the ape deserting its offspring under certain conditions,
may be taken as an evidence of its superior intelligence and its
appreciation of life and danger, rather than a low, brutish impulse. It
is the exercise of superior judgment that causes man to act with more
prudence than other animals. It does not detract from his nobleness.
Within the family circle of the chimpanzee the father is supreme;
but he does not degrade his royalty by being a tyrant. Each member
of the family seems to have certain rights that are not impugned by
others. For example, possession is the right of ownership. When one ape
procures a certain article of food, the others do not try to dispossess
it. It is from this source, doubtless, that man inherits the idea of
private ownership. It is the same principle amplified by which nations
hold the right of territory, but nations often violate this right, and
so do chimpanzees when not held in check by something more potent than
a sense of justice. With all due respect, I do not think the ape abuses
the right by urging his claim beyond his real needs, while nations
sometimes do.
When a member of a family of apes is ill, the others are quite
conscious of it, and evince a certain amount of solicitude. Their
conduct indicates that they have, in a small degree, the passion of
sympathy, but the emotion is feeble and wavering. So far as I know,
they do not essay any treatment, except to soothe and comfort the
sufferer. They surely have some definite idea of what death is, and
I have reason to believe that they have a name for it. They do not
readily abandon their sick, but when one of them is unable to travel
with the band, the others rove about for some days, within call of it,
but do not minister to its wants.
It is said, if one of them is wounded, the others will rescue it if
possible, and convey it to a place of safety; but I cannot vouch for
this, as such an incident has never come within my own experience.
One of the most remarkable of all the social habits of the chimpanzee,
is the _kanjo_, as it is called in the native tongue. The word does not
mean "dance" in the sense of saltatory gyrations, but implies more the
idea of "carnival." It is believed that more than one family takes part
in these festivities.
Here and there in the jungle is found a small spot of sonorous earth.
It is irregular in shape, but is about two feet across. The surface
is of clay, and is artificial. It is superimposed upon a kind of
peat bed, which, being very porous, acts as a resonance cavity, and
intensifies the sound. This constitutes a kind of drum. It yields
rather a dead sound, but of considerable volume.
This queer drum is made by chimpanzees, who secure the clay along the
bank of some stream in the vicinity. They carry it by hand, and deposit
it while in a plastic state, spread it over the place selected, and let
it dry. I have, in my possession, a part of one that I brought home
with me from the Nkami forest. It shows the finger-prints of the apes,
which were impressed in it while the mud was yet soft.
After the drum is quite dry, the chimpanzees assemble by night in great
numbers, and the carnival begins. One or two will beat violently on
this dry clay, while others jump up and down in a wild and grotesque
manner. Some of them utter long, rolling sounds, as if trying to sing.
When one tires of beating the drum, another relieves him, and the
festivities continue in this fashion for hours.
I know of nothing like this in the social economy of any other animal,
but what it signifies, or what its origin was, is quite beyond my
knowledge. It appears probable that they do not indulge in this _kanjo_
in all parts of their domain, nor do they occur at regular intervals.
The chimpanzee is averse to solitude. He is fond of the society of
man, and is easily domesticated. If allowed to go at liberty, he is
well-disposed, and is strongly attached to man, but if confined, he
becomes vicious and ill-tempered. All animals, including man, have the
same tendency.
Mentally the chimpanzee occupies a high plane within his own sphere of
life, but within those limits the faculties of the mind are not called
into frequent exercise, and therefore they are not so active as they
are in man.
It is difficult to compare the mental status of the ape to that of
man, because there is no common basis upon which the two rest. Their
modes of life are so unlike, as to afford no common unit of measure.
Their faculties are developed along different lines. The two have but
few problems in common to solve. While the scope of the human mind
is vastly wider than that of the ape, it does not follow that it can
act with more precision in all things. There are, perhaps, instances
in which the mind of the ape excels that of man, by reason of its
adaptation to certain conditions. It is not a safe and infallible guide
to measure all things by the standard of man's opinion of himself. It
is quite true that, by such a unit of measure, the comparison is much
in favour of the man, but the conclusion is neither just nor adequate.
It is a problem of great interest, however, to compare them in this
manner, and the result would indicate that a fair specimen of the ape
is in about the same mental horizon as a child of one year old. But
if the operation were reversed, and man were placed under the natural
conditions of the ape, the comparison would be much less in his
favour. There is no common mental unit between them.
The chimpanzee exercises the faculty of reason with a fair degree of
precision, on problems that concern his own comfort or safety. He is
quick to interpret motives, to discern intents, and is a rare judge
of character. He is inquisitive, but not so imitative as monkeys are.
He is more observant of the relations of cause and effect, and in his
actions he is controlled by more definite motives. He is docile, and
quickly learns anything that lies within the range of his own mental
plane.
The opinion has long prevailed that these apes subsist upon a vegetable
diet, but such is not in anywise the case. In this respect their habits
are the same as those of man, except that the latter has learned to
cook his food, while the former eats his raw.
Their natural tastes are much diversified, and they are not all equally
fond of the same articles of food. Most of them are partial to the wild
mango, which grows in abundance in certain localities in the forest,
and is often available when other kinds of food are scarce. It thus
becomes, as it were, a staple article of food. There are many kinds of
nuts to be found in their domain, but the oil palm nut appears to be a
favourite. They also eat the kola nut, when it is to be had. Several
kinds of small fruits and berries also form a part of their diet. They
eat the stalks of some plants, the tender buds of others, and the
tendrils of certain vines, the names of which I do not know.
Most of the fruits and plants that are relished by them are either
acidulous or bitter in taste, and they are not especially fond of sweet
fruits, if they can get those having the flavours mentioned. They eat
bananas, pine-apples, and other sweet fruits, but not from choice. Most
of them appear to prefer a lime to an orange, a plantain to a banana,
or a kola nut to a sweet mango, but in captivity they acquire a taste
for sweet foods of all kinds.
In addition to these articles they devour birds, lizards, and small
rodents. They rob the birds of their eggs and their young. They make
havoc on many kinds of large insects. Those that I have owned were fond
of cooked meats and salt fish, either raw or cooked.