ALMOST HUMAN
THE BRAIN OF THE GORILLA
The largest member of the ape world is the gorilla. There is much
dispute to-day concerning the place he occupies in relation to man,
and also as to what rating his intelligence deserves. Neither of these
questions can be settled at present. His case, in fact, requires much
more study than has yet been given to it. Recently the gorilla has
been befriended by several famous African explorers like the Bradleys
and the late Mr. Carl Akeley. They have given him a rather favourable
recommendation as an inoffensive and retiring animal. In spite of this
vindication, however, most persons who have any acquaintance with him
regard the gorilla as a dangerous, savage brute. Standing upright, he
is nearly as tall as the average man. Sometimes his height reaches six
feet, and often the adult male attains the great weight of nearly four
hundred pounds.
_A Superlative Fighting Machine_
The body of the gorilla is stout and large. His legs are short but
his arms are extremely long. When standing erect the tips of his
fingers reach to about the middle of the leg below the knee. His huge
and grizzly head, flat, broad nose, prominent muzzle, large mouth,
very large canine teeth, and protruding ears all give the animal a
terrifying appearance.
The manner in which he rises on his hind legs and makes the forest
reverberate with his roars when attacked is one reason why the gorilla
is considered the most savage of all beasts. His hands are large and
thickly covered with black hair on the back. The palms of the hands
have no hair. They possess many grooves and markings with strong human
resemblances. The thumb is somewhat short for the size of the hand,
but is thick and bears a broad nail. The animal’s body as well as the
head up to the brow line is covered with thick, black, shaggy hair. The
skull is massive and heavy. The eyes are surmounted by a heavy ridge
of bone, and a thick bony crest extends from the bridge of the nose to
the back of the skull along the middle of the head. All of these bony
structures provide the gorilla with a most effective fighting helmet.
The massive head, the short neck, the powerful arms, and the savage
teeth create the impression of a superlative fighting machine--a sort
of dreadnaught. But this machine has one inherent weakness. The feet
and legs are inadequate for a finished fighter. The gorilla is able
to assume the upright position and walks thus in an awkward manner,
using the arms in balancing. In the main, however, he goes on all
fours, especially when making speed through the underbrush or climbing
among the trees. He rises upon his hind legs largely for purposes of
inspection in order to make a survey of the surrounding territory.
Many species have been identified. They all live in Africa. One variety
inhabits the Gaboon in West Africa. It also extends into regions of
southern and northern Cameroon, near the border of the French Congo.
This variety of gorilla is especially adapted for forest life. Another
type, sometimes spoken of as the mountain gorilla, inhabits mountainous
localities in the Belgian Congo.
_The Gorilla’s Ancient Disrepute_
The gorilla has been long and unfavourably known to mankind. Ancient
rumour of him spread abroad many unsavoury reports about his savage
disposition. In the Fifth Century B. C. gorillas were first spoken of
as wild, hairy men living in Africa. The Carthaginian Admiral Hanno,
in his famous voyage to the Pillars of Hercules, appears to have been
the first white man to encounter them. He and his comrades unexpectedly
came upon a group of these wild people. All of the men fought so
savagely that they made their escape, but Hanno and his friends were
able to capture three of the women. These females were so ferocious
and unfriendly that it was necessary to kill them. Their skins were
preserved, taken to Carthage, and there placed in the Temple of Juno,
where they were held sacred until that city was destroyed.
The famous explorer, Paul Du Chaillu, in his _Explorations and
Adventures in Equatorial Africa_ describes the gorilla as gregarious.
He found them going about in companies of eight or ten. Sometimes the
older males become superannuated. Then they live solitary lives apart
from these small communities. When grown old they appear actually
grizzled with age, and the hair, which in youth is black, becomes
almost white. Du Chaillu was probably the first European to kill a
gorilla in its native forest. His description of their habits was
thought to be an exaggeration, but later information largely upholds
his opinion. He believed that the gorilla did not, as often claimed,
lurk in the trees just above the roadside in order to reach down with
his great arms and snatch up the unsuspecting passer-by. He discredited
the ancient story that these animals attack elephants and beat them
to death with sticks, and that they carry off native women to devour
them in the depths of the forest. He did not even believe that the
gorilla built itself houses or nests from twigs among the trees, or
that large bands of them made attacks upon men whose homes were in the
neighbourhood of the forest. Du Chaillu reported that the gorilla lives
in the loneliest portions of the dense African jungle. It is seldom
found in the same place two days in succession. It prefers deep wooded
valleys or rugged heights and roams about over a large area in search
of food. It consumes a large amount of food, such as pineapple leaves,
berries, wild sugar cane, and other vegetable matter. The animal sleeps
sitting on the ground with its back against the trunk of a tree, and
when full-grown seldom ascends high among the branches. The young sleep
in the trees, and possibly the females may occasionally do so.
_Like Some Monster of a Nightmare_
In spite of their reputation to the contrary, the gorillas are in
reality shy. The female will run to shelter at the first sound of
alarm, carrying her young one with her. The male, however, is less
hurried in his retreat. In fact, he seems to act upon the theory that
the best defense is an attack. He rises up on his hind legs for a
moment, showing his savage face among the underbrush. Then, glaring at
the intruder, he begins to beat his chest with his closed fists, at
the same time uttering a deep, terrifying roar. This sound begins at
first as several loud barks like those of a dog and then changes to a
deep-throated growl, which is emitted with redoubled force, causing
echoes in the forest like distant thunder. Du Chaillu said that the
horror of the animal’s appearance at this time is beyond description.
It seems like some monster of a nightmare, an indescribable piece of
hideousness.
In walking, the gorilla waddles from side to side as he proceeds upon
his hind legs. Meanwhile, in order to balance himself, he swings his
great arms at his sides, which makes him appear more determined and
awe-inspiring. When attacking, his features are distorted by hideous
wrinkles, and his lips are drawn back revealing long fangs in the
powerful jaws by which a human limb could easily be crushed.
The celebrated African explorer, Mr. Akeley, has pointed out that there
is no difficulty in shooting the gorilla. In fact, against modern
firearms this animal is as defenseless as a crippled woman. Such
hunting is thoroughly distasteful and seems to be an atrocity closely
akin to murder. It was due to Mr. Akeley’s efforts that the King of
Belgium recently set aside a large territory in the Congo as a gorilla
sanctuary, in which all hunting of this animal is prohibited. Here, in
the vicinity of the three extinct volcanoes, Mt. Keno, Mt. Karissimbi,
and Mt. Visake, Mr. Akeley hoped that a biological station might be
established for the further study of the gorilla’s behaviour. In this
sanctuary, now known as Albert National Park, he believed it would
be possible to gain a footing on close and intimate terms with this
gigantic ape. Mr. Akeley was convinced that the gorilla’s reputation
for ferocity was greatly exaggerated, and that the animal was actually
a timid and retiring beast. This new estimate of the gorilla’s
disposition gives encouragement to the expectation that in time this
fast-disappearing offshoot of the prehuman stock may furnish its full
testimony concerning the evolutionary process.
_Training the Young Gorilla_
In adult life the gorilla is untamable. If captured young, as much may
be done with it as with many other apes in captivity. The following
account of a gorilla’s life in civilization, given by Miss Alyse
Cunningham, of London, testifies to this fact. It is the story of the
young gorilla called “John Daniel the First.” The record was made by
Miss Cunningham herself. At first she had no fancy for this animal; in
fact, she felt rather a dislike for anything in the shape of a monkey
or an ape, but she soon became interested in the young gorilla and took
his education seriously in hand. The animal was presented to her by her
nephew, Major Penny, shortly after the end of the Great War. He was
much interested in apes and bought the gorilla with the idea of seeing
how much mentality it possessed and how much it could be developed.
John Daniel was captured when very young in the French Gaboon country
and came to England when he was about three years of age. Major Penny
first saw the young gorilla on exhibition, during the Christmas
holidays, in a large show window of a well-known shop in London. The
animal attracted much attention and large crowds gathered daily to
watch him. As a dry-goods advertisement he was a splendid investment,
but unfortunately at that time he was suffering from rickets. With
the severe changes of weather in the Christmas season he contracted
an attack of influenza. On this account his owners were compelled to
retire him from his advertising post and found themselves at their
wit’s end to know what to do with this sick infant gorilla. When he was
finally sold to Major Penny his original owners did not think he would
survive for very long. In this respect their calculations went astray.
Miss Cunningham took the sickly gorilla, nursed him as she would a
child, brought him through his influenza, and so successfully cared
for him that during the next three years he reached the weight of 112
pounds and the height of three feet four and a half inches. Meanwhile,
he acquired many of the habits and adjustments necessary to fit him as
an interesting if somewhat unusual member of the household.
_John Daniel the First_
We are indebted to Miss Cunningham for the excellent account of his
life, which indicates the extent to which this great ape may be
trained and educated. Little John, immediately after his recovery from
influenza, began to show some singularly childlike emotions. He was
gentle and affectionate in response to the tender care he received. But
he became too much attached to his new and kind friends. His devotion
in this respect created some difficult situations in the household.
If he were left by himself at night he would shriek from fear and
loneliness. Perhaps he remembered the long and cheerless nights when
he was a Christmas exhibit in the department store. In any event,
Miss Cunningham was forced to treat him just as she would any little
child. She coaxed and soothed and petted him until she had allayed his
fears. Then he would become quiet and fall asleep. But even this was
not sufficient. It soon became necessary to place her nephew’s bed
in the room adjoining the cage of the gorilla. Apparently he craved
companionship of some kind and at length became quite happy under this
new arrangement.
John soon began to grow and to put on weight. He gradually got over his
rickets. At first he was taught to be clean in his habits by a system
of rewards and punishments. At the end of six weeks he was thoroughly
housebroken. At this time he was taken out of his cage and allowed the
freedom of the house. Thereafter, John would always run upstairs to the
bathroom of his own accord. He would turn the knob of a door and took
pains to see that he always left it closed behind him. He showed strong
likes and dislikes in the matter of food. There was one feature that
always puzzled Miss Cunningham in this respect. Generally speaking,
John was not a thief. He manifested average honesty, but when it came
to food he much preferred to steal it than have it given to him. It
was difficult to understand the motive underlying this course of
action. There were some things about it that seemed to indicate a real
satisfaction derived from stealing, due, perhaps, to an outcropping of
his native cunning. Perhaps it was the consequence of a well-recognized
quality of natural aloofness characteristic of the gorilla in general
that made John Daniel averse to receiving favours from others. He would
always avoid any food that had been exposed to the air for long. He
was particularly fond of oranges and apples, but would never eat them
if they had been cut a few hours. John had what almost amounted to a
passion for eating roses. The more beautiful they were, the more he
seemed to like them, but nothing would induce him to eat faded roses.
Nuts he did not much care for, although at times he showed a liking for
walnuts. A cocoanut was always a problem to him. It was most amusing to
see how he went about this problem. He understood that it was necessary
to break the cocoanut. First he would throw it upon the floor, but
failing to break it this way he would finally bring it to one of the
members of the family with an appealing look for help. If given a
hammer he would use it viciously on the nut, but never effectively.
After several failures John would take the nut and the hammer to
someone, indicating what he wanted.
_John’s Social Behaviour_
John had a good understanding of tools, almost too good, in fact. In
consequence, hammers, chisels, and saws were kept in hiding, and if
John happened to find them he was apt to indulge in a somewhat ruthless
carpentry on the household furniture. From his babyhood, and while he
was growing up, he was always fond of people. He liked to have them
come to visit him at his home. Far from being timid and shy, he was
quite the reverse. Whenever there were visitors he always liked to show
off, just like a child. He would take the visitor by the hand and lead
him round and round the room. This amused John greatly, and if his
guest responded playfully all went well, but if there was any sign of
nervousness or fear John took an impish delight and would run by the
visitor, giving him a smack on the leg. Then, perching himself on a
chair, he would grin foolishly at his own mischief. This was the only
blemish on his company manners, and he always appeared a bit shamefaced
when rebuked for such misbehaviour. He did not, however, go the length
of making apologetic overtures to his offended visitor, but kept
himself aloof with an air of injured innocence.
Miss Cunningham had few misgivings about John when she had company in
the home. He was always very obedient to her and seemed to recognize
that her wishes were law. It hurt him apparently to be guilty of
any act which caused her displeasure, and while sometimes he would
perpetrate some mischief on the sly he would always be on his best
behaviour when he felt Miss Cunningham’s eye upon him. His table
manners were rather good. He always sat at the table, and when the
meal was ready would pull up his chair to the designated place. He
never cared for great quantities of food, and his actions at table
required little, if any, more reproval than did an ordinary child. He
was especially fond of drinking water from a tumbler. He always took
afternoon tea with the family. He had a particular liking for this
beverage and with it would eat a thin slice of bread with plenty of
jam. He also liked his demi-tasse of coffee after dinner. The family
estimate of him was generally high. He was regarded as the least greedy
of all the animals that had ever come under the observation of his
owners. He would never snatch for anything at the table, and he always
ate slowly. He was accustomed to drink large quantities of water,
which he got for himself whenever he wanted it by turning on the tap.
Strangely enough, he always turned off the water when he had finished
drinking.
_A Gorilla with a Sense of Humour_
John Daniel had a very good opinion of himself. He was quite well
poised and self-contained. Nothing seemed to ruffle him, and he could
amuse himself in simple ways by the hour. He seemed to believe that his
own estimate of himself was shared by others and appeared confident
that everyone was delighted to see him. Often he would stand on the
window sill and throw up the shade. In a short time a large crowd
would collect on the street below to watch this unusual sight at the
window. He enjoyed such publicity immensely and would stand watching
the people for a long time. Once in a while, if the crowd grew very
large, he would pull the shade down deliberately in their faces and run
away shrieking with laughter, in a way which seemed to indicate that
he was conscious of having perpetrated a huge joke upon his audience
outside. Of course, this entire reaction and the motives underlying it
are open to several interpretations. Skeptics will say that the version
here given endows the gorilla with attributes more human than he could
possibly possess. However that may be, those who actually observed
these performances were impressed by the fact that John Daniel did act
in a seemingly human manner.
_Fondness for Little Children_
John was especially attached to Miss Cunningham’s three-year-old
niece, who often came with her mother to stay at the house. They
would play together by the hour. The gorilla seemed to know just what
this little girl wanted him to do. If she cried for any reason, when
her mother came to pick her up, John would give the mother’s hand a
nip with his teeth or slap her with the full weight of his palm,
apparently thinking that she was the cause of the child’s grief. One
day Miss Cunningham was dressed for going out, and John Daniel wished
to sit on her lap to bid her good-bye. It chanced that her gown was a
light-coloured one, and she pushed him away, saying that she feared he
might soil her dress. Poor John was deeply distressed. At once he lay
down on the floor and cried like a baby for a moment. Then he looked
around the room, found a newspaper, laid it on Miss Cunningham’s lap,
and climbed up on it. This was the cleverest thing he had ever done.
Those who saw it said they would not have believed it had they not
themselves been present.
_Like a Child in Play_
John Daniel apparently could stand a good deal of cold weather. He
would often climb out on the roof when the thermometer was below the
freezing point. He did not seem to mind how cold it was so long as he
could come back into a warm room when he wanted to. Then he would go
directly to the fire, rub his chest, and sit down with his feet cocked
up on the fender. Exercise was necessary to keep him in good health,
and John got much of this by playing hide-and-seek with Major Penny.
In the morning before breakfast and in the evening before dinner the
Major would run up and down stairs, in and out of all the rooms. The
game appeared to delight the gorilla, who would giggle and laugh while
being chased. He never took any chances about going into a dark room,
however. Invariably he would make sure to turn on the light first.
It was his habit to retire each night at eight o’clock, and it was not
necessary to tell him to do so more than once. He had his own little
room adjoining that of Miss Cunningham’s nephew, in which he had a
spring bed of his own, with blankets and pillows. At night he would
get up out of bed by himself, go back to bed, and pull the blankets
up over himself quite neatly. One of John’s greatest pleasures was to
stand on the top rail at the foot of the bed and jump on the springs,
just like a little child. He was never taught any tricks, but simply
acquired knowledge by himself. In the summer time John was taken by
train to the family’s cottage in the country. He occupied his seat in
the railway coach like any other passenger, without so much as a chain
around his neck. When out of doors the broad fields and open country
seemed to terrify him, but he was singularly happy and contented in the
quiet garden or in the woods. He seemed to fear full-grown sheep, cows,
and horses, but colts, calves, and lambs attracted and amused him. It
seemed to those who cared for him that he recognized youth and was
sympathetically drawn to it.
_John Becomes Famous_
As the years passed he became more devotedly attached to the family.
If left alone he would make a great noise, shrieking and crying. This
tendency increased, so that after three years it was necessary to make
some other arrangement for him. Through a misunderstanding which his
owners have always regretted, John was sold to a circus. He was taken
across the Atlantic to New York. Here, after a month’s separation from
his devoted friends during which time he refused to take food and
showed every sign of real homesickness, he died in the tower of the old
Madison Square Garden, in April, 1921.
Many of the New York daily papers published a notice of this remarkable
ape’s death, telling how the gorilla, John Daniel, homesick and
disconsolate without those who had befriended him, died of a broken
heart. The skeleton and taxidermic preparation of this gorilla, who has
contributed so much to our knowledge and understanding of the great
apes, may be seen in the anthropoid collection in the American Museum
of Natural History, bearing the label “John Daniel.”
_A Gorilla at Afternoon Tea_
As an interesting sequel to this history of what appears to be the
first gorilla raised under the conditions of such intimate domestic
life, it may be added that Miss Cunningham secured another gorilla,
which she called “John Daniel the Second.” John Daniel the First was
a little over six years old when he died and was then less than half
grown. These two great apes resembled each other closely in their
emotional reactions and in their responses to training. Both were about
of the same age. John the Second was perhaps a less likable individual
and had a disposition more in keeping with the ancient reputation
of gorillas. Several years ago, while he was visiting in New York, a
number of scientists were invited to have afternoon tea with him at a
certain fashionable hotel. On this occasion the troglodyte host was
found seated in a comfortable chair. He displayed much gravity and
apparent enjoyment as he drank from a cup of tea. During the course of
conversation John the Second was for a moment not the actual centre
of attention. Suddenly he dashed across the room with unbelievable
swiftness and attacked one of his visitors with repeated rapid blows of
both fists in the neighbourhood of the solar plexus. Just as quickly
he hopped over the foot of the bed and from this point of vantage
watched the discomfiture of his guest. A moment later, when less
sharply watched, he hurled his full weight in most approved football
style against a distinguished professor of zoölogy, who, as a result,
was thrown from his chair. In the intervals between these presumably
playful diversions this powerful gorilla sat quietly. Yet, in spite
of his innocent demeanour, one was suspicious that he was casting
about for the next piece of mischief that he might perpetrate. There
was a degree of roughness and sudden strength in the playfulness of
this young gorilla that afforded some idea of the terrific power these
animals must possess when full grown.
The attractive prospect of a biological station in Africa, as
suggested by the late Carl E. Akeley, for the study of the gorilla is
inspiring. It should be possible under these circumstances for one
scientifically inclined to saunter into the jungle of a morning, call
to some particularly promising gorilla, and with the troglodyte spend
many profitable hours in biological study. If the full-grown gorilla,
however, is anything like John Daniel the Second, this studious
occupation might not prove so simple. Indeed, it seems probable that
only the most hardy of human adventurers will ever enjoy the privileges
of anything approaching a familiar acquaintance with these giant apes.
Such adventurers may live to report that the great brutes have acquired
no marked degree of gentleness even in their own gorilla sanctuary.
_The Art of Capturing Young Gorillas_
On a number of occasions young gorillas have been captured alive. Mr.
Ben Burbridge, using some clever tactics, has succeeded in capturing
several small gorillas. The approved style of such hunting is to lure
the young animal away from the older gorillas; then, grasping the
throat, force it to the ground until helpers arrive to slip a stout
bag over its head. On one occasion Mr. Burbridge succeeded in artfully
luring a gorilla from the rest of his family. He at once proceeded to
seize him in the usual manner. Immediately he realized that he had
caught a tartar. The young gorilla was much stronger than any man, and
grasping both of Mr. Burbridge’s hands he forced them into his savage
mouth. Nothing but iron nerve and quickness of wit would have saved a
man under these circumstances. Realizing his inability to overpower the
gorilla or free himself from its vise-like grip, Mr. Burbridge did the
only thing left for him to do. He thrust his hands down the animal’s
throat as far as they would go. Several natives finally succeeded in
overpowering and binding the young giant. The first burlap bag put
over his head he split asunder like a piece of gauze. At length he was
bound and carried off to camp. But this young monarch of the volcanic
mountain sides would not accept captivity. He was unapproachable and so
actively hostile that he soon died. Later, Mr. Burbridge succeeded in
capturing and bringing home to Florida a small female gorilla, weighing
sixty-five pounds, which he called “Congo the Second.”
_Professor Yerkes Studies “Congo the Second”_
We are extremely fortunate that this gorilla has been studied by
Professor Yerkes, who in a book recently published, called _The Mind
of a Gorilla_, has given us another of his brilliant works on animal
behaviour. This is a most readable account of Congo’s actions, and
those who wish further information will derive much pleasure from
Professor Yerkes’s story. All of his observations are illuminating and
helpful in understanding the brain of this great troglodyte.
The mountain gorilla, as Professor Yerkes points out, is built for
strength rather than speed. Congo, although still in her childhood,
and weighing only sixty-five pounds, was amazingly strong. She could
lift weights and overcome resistances that required the full strength
of a grown man. In her play with a young Airedale terrier she became
so rough that the dog finally avoided her. Her climbing among the
trees, about which she seemed eager, was scarcely any better than that
of an active small boy. It was easy to outrun her and throw her off
her balance. The tremendous strength of the gorilla must, therefore,
be looked upon as the real secret of his success in life. Without this
strength he probably would not have survived, since he has neither the
skill in climbing nor the speed upon the ground to escape his deadly
enemies. His deadliest foe is the leopard. This stealthy and powerful
cat often steals up to a gorilla family and snatches away the little
ones. The gorilla’s sole defense against the leopard is his gigantic
strength. If at present this great ape is threatened with extinction it
is because his natural enemies are increasing in number. Man with his
modern equipments must be listed among these hostile contemporaries.
For ages the struggle between the gorilla and his enemies in the jungle
has been going on relentlessly. The great ape has been able to maintain
that margin of superiority which permitted his kind to come down into
modern times.
Professor Yerkes devised a series of tests for determining the mental
capacity of the young gorilla, Congo the Second. These were arranged in
several groups such as the following:
1. The use of the stick as an implement.
2. The use of simple mechanisms showing adaptive ability.
3. The uses of boxes and piling boxes.
4. Tests for memory.
5. Observations of social relations.
6. Study of emotions and incentives to action.
_The Mind of a Gorilla_
In all, twenty-four tests were employed in the experiments to fathom
Congo’s mind. Among them were the stick used as an implement, a
buried jar of food, food suspended and made accessible by using the
stick, food suspended and made accessible by piling boxes one on top
of another, the use of hammer and nail in imitation of a man using
the same implements, the mirror test and the animal’s reaction to
the looking-glass. Professor Yerkes carried on his studies through
a number of weeks on two different occasions. The first series was
conducted in January, 1926, and the second series, largely repeating
the conditions of the first, in January, 1927. During this time the
little gorilla had grown and prospered. She had doubled her weight in
twelve months and she manifested many changes in her behaviour. In
the first place, she had become somewhat destructive, although when
she first came to Shady Nook in Florida this was not the case. Her
curiosity had increased as had also her powers of imitation and her
emotional expressions. She was much more self-reliant and likewise more
coöperative. She showed a very considerable improvement in her ability
to solve the problems of the several tests given to her. In using
the stick she manifested greater cleverness and adaptability, with
some indications of real insight into the situations that confronted
her. There were signs also that she had gained a greater degree of
adaptability in the use of simple mechanisms. These appliances in her
earlier tests baffled Congo, but upon repetition a year later she not
only gave evidence of memory concerning the tests but also had more
ability in solving the problems which she had previously failed to
master. She showed much improvement, particularly in piling boxes one
upon another. Certain memory tests, which were unsuccessful in January,
1926, were quite successfully performed in January, 1927. Heretofore,
no animal except man has been capable of correct response in these
particular memory tests. Congo’s success possibly demonstrates the
existence of a mechanism in the gorilla brain that is possessed by the
most highly organized animals only. It is this mechanism, doubtless,
which distinguishes man and the great apes from all other mammals.
Buried food tests also demonstrated an ability to remember after
intervals of one or two days. Congo’s emotions likewise had changed.
At first she appeared aloof, independent, and inexpressive. She still
remained reserved, and although playful she was highly self-controlled.
Her emotional expression by voice, face, and attitude was rare, and
seldom appeared in response to definite provocation. Her incentives
and motives seemed much more complex than in lower animals, like rats
and guinea pigs. Congo was moody, having her good days and bad days in
doing the tests. The inducements offered her to perform certain acts
did not have the same certainty that they have with lower animals. In
her social relations she was extremely simple. She apparently gained
an increased interest in those with whom she was familiar and also with
strangers. She enjoyed visitors and acted in a limited way to entertain
them. Seeing herself in the looking-glass, she had a marked interest
in her image. In the second series of tests her interest in the mirror
seemed more intelligent than the first. In sexual interest Congo showed
a marked development. At first she manifested nothing resembling
sex play, but in the course of the year this became evident in her
relations with her dog companions and other objects. Ultimately she had
a decided preference for the male dog.
_Mental Comparisons of the Great Manlike Apes_
Professor Yerkes’s comparison of the behaviour of the three great apes,
the orang, the chimpanzee, and the gorilla, is particularly interesting
and important. He carefully guards his statement by acknowledging that
these are rough comparisons based on the intimate study of only a few
individual apes. The physical differences between these anthropoids may
have a definite bearing upon their mental characters. The chimpanzee
is well but lightly built. The orang, in contrast, is loosely built,
with arms that seem much too long and liable to be in the way. The
gorilla is stocky, somewhat clumsy, but of impressively strong build.
The general disposition of these three apes varies somewhat according
to their physiques. The chimpanzee is sanguine, buoyant, alert, and
snappy. The orang-outang is melancholy and taciturn. The gorilla is
reserved and aloof almost to the point of manifesting a superiority
complex. In their attitude toward others and things in general this
same difference is observed. The chimpanzee is preëminently a leader
in playfulness and invention of ways to amuse himself. He is quick,
impulsive, energetic, and comical. He has much enthusiasm and optimism,
all of which makes him the showman’s prize. The orang is more slow
and cautious, with little impulsiveness and no show of optimism. He
seems more stable and dependable than the chimpanzee. He is certainly
more readily depressed and discouraged than his livelier cousin. The
gorilla is calm, reserved, cool, and calculating. His disposition
is quite the opposite of that of the chimpanzee. The terms sullen,
morose, ferocious, and unrelenting did not, however, apply to Congo,
who was placid, self-dependent, and usually superior to the incidents
of her artificial life in captivity. In curiosity the chimpanzee heads
the list. The orang is a close second. The gorilla may be stirred to
curiosity, but under such circumstances usually acts as though he
considered himself superior to such childish indulgence. The manner
and methods of learning in these three great apes are remarkably
interesting. In learning by imitation from man, the chimpanzee has
a long lead. The orang is not entirely unsuccessful in this matter,
but the gorilla, especially as typified by Congo, shows an actual
resistance to learning by imitation of man. The ability to acquire
new habits and adjustments to life by means of trial and error
shows that the great apes rank as follows: Chimpanzee first, orang
second, gorilla third. Learning by ideas, experience, insight, and
understanding seems to reverse this order and puts the gorilla at the
head of the list.
Professor Yerkes appears to think that, as compared with chimpanzees
and orangs of like age, Congo was remarkably slow in adapting herself
and was more limited in initiative, originality, and insight. He
concludes that the general tendency to rate the gorilla in a mentally
higher class than the chimpanzee or orang finds no support from his
study of Congo. He also believes that conclusions based on a single
specimen of this great ape are not sufficient to determine the mental
rating of the gorilla. This animal, like the chimpanzee and the orang,
indeed like man himself, has great individual variations in mental
development.
Such records as those of John Daniel, First and Second, made by
observers little trained in the technical methods of behavioural study,
must of course be accepted with some reservations. Viewed in the light
of Professor Yerkes’s studies on Congo, they do afford an illuminating
picture of the gorilla’s mental capacity, disposition, and ability to
learn. To say the least, in all of these qualifications the largest
of the great apes is strikingly human. Its brain, which weighs and
measures more than that of other apes, is in many respects nearer to
the brain of man. In the gorilla’s brain it is possible to discern
the process by which the progressive development of this organ has
made great strides. All of the landmarks of the superbrain are more
distinctly human in their arrangement and disposition than in the
chimpanzee or orang. If the chimpanzee’s brain is a human miniature,
the resemblance to man in gorilla has become still more striking. The
position of the Sylvian groove and of the ape groove marks the boundary
of the two great departments of sight and hearing. In the gorilla
both of these have increased the area for radiating brain power. The
convolutions in both of these regions bear a close resemblance to those
of the human brain. This similarity is likewise true in the department
for body and contact sense, where the convolutions have increased in
complexity as well as in relative size. The central groove forms the
boundary for a well-defined frontal lobe. If it were possible to make
a measurable contrast of this permanent headquarters for the higher
faculties in gorilla to that of chimpanzee, it seems fair to say that
the gorilla would show some slight advantage. This advantage may
account for the gorilla’s greater reserve, which in some ways indicates
a more mature attitude toward life, especially when compared to the
restless and more childlike behaviour of the chimpanzee.
_Secret of the Gorilla’s Survival_
Professor Yerkes would perhaps be unwilling on the strength of his
studies to admit any measurable degree of superiority on the part of
the gorilla’s mentality over the chimpanzee. Unquestionably this is a
proper point of view in the light of those great apes which have been
available for experiment and investigation. In the main, such gorillas
have been both too young and too few in number to permit any just
estimate of their real ability. One fact in their history does speak
forcibly in behalf of their mental superiority over all other apes. In
form and physique the gorilla occupies an intermediate position. He is
not well adapted for great successes living upon the ground. He is too
heavy to capitalize the full advantages of living in the trees. Added
to this is the fact that he is both slow and clumsy. His one physical
asset in the struggle for life is his gigantic strength. By means of
this advantage he has been able to meet all comers of the wild, to
contend with such deadly enemies as the leopards and other members
of the great cat family. He has eked out an existence in a territory
filled with all manner of hazards. Yet in spite of his handicaps he has
not only held his place in nature but he has kept his line a vital and
going concern with all the increasing odds against him. This success
in adjustment must depend upon something more than mere chance. We are
perhaps fair in assuming that added to his chief asset of brute-like
strength there have been certain superior mental qualities derived from
a superbrain and particularly from a frontal lobe which surpassed that
of all his animal competitors.
The index of his powers to adjust himself to a strenuous life is shown
by his bridge (_pons_). This gives him a rating of .480, which is
still higher than in the case of the chimpanzee. Most interesting in
this connection is the fact that the pyramid in the gorilla is .161,
which is considerably less than in the chimpanzee. The pyramid, as
will be recalled, indicates the degree of skill that an animal has in
controlling its voluntary movements; that is, in making its muscles act
in many and varied ways according to the dictates of the will. That the
agile, speedy, and acrobatic chimpanzee should surpass the clumsy and
slow-moving gorilla in this particular might be expected. In almost
every other detail of its development the brain of the gorilla is
nearer to man than is the brain of any other ape, great or small. Those
who have studied this question are fully convinced of the near approach
in brain structure which all three of the great manlike apes make to
the human brain. If any final estimation is justified at the present
time, the gorilla’s brain appears to be the most advanced of all the
apes and is, in fact, almost human.