CAPUCHINS (SUBFAMILY CEBINAE)
From Grzimek's Encyclopedia, Vol. 3
The true capuchin monkeys, the sixth subfamily (Cebinae) of the capuchin-like New World
monkeys, have a curling tail, but its use as a fifth hand is quite limited. They are indeed able to
hang by it and pick up sticks or food with it, but they use it mostly as an anchor in traveling
through their habitat. Quadruped running, climbing, and leaping as well as biped running and
hopping can be observed. The animals are impressive as acrobats. Capuchins live in all forest
regions of South America; they are the most robust of the monkeys to be found there, and
therefore they have been seen for many years in the menageries and zoological gardens of Europa.
Because of their liveliness, their intelligence, and agility, they best typify the popular conception of
a monkey.
Capuchins live in large social groups. Usually the number of females is greater than the number of
males, and half the group will comprise juveniles of various ages. Capuchin groups are cohesive;
males will change groups occasionally, but basically the entire group is defended, the males
fighting with the males of other groups. Capuchins are active throughout the day. In the morning
twilight, the young are the first to leave the sleeping trees; until evening, all are busy foraging --
with the interruption of a good midday nap. Capuchins find food in every corner of their habitat,
and so are to be found on the forest floor as well as in the highest crowns of the trees. In the search
for food, the group spreads out -- especially in pursuit of insects -- within a radius 320 ft 100 m,
often separating some individuals from the group entirely.
Representatives of different species meet in this way, and may associate with other temporarily.
Capuchins are encountered in the company of squirrel monkeys, howler monkeys, spider monkeys,
and woolly monkeys. Social contacts between the various species are observed regularly.
Sometimes, however, individuals of different species will quarrel. Like the squirrell monkeys,
capuchins also wash with urine and erect the penis or clitoris when excited, though the case would
not seem to be one of intimidating display.
A large colony of the Hooded, or Brown Capuchin (Cebus apella) has been kept at our primate
center for about a decade. Since our largest social group of more than 30 individuals is not only
the largest group of capuchins ever kept in captivity, but also the only social group of cebine New
World monkeys that has been under regular (daily) and uninterrupted observation for years, we
should like to give some further account of their social life.
Our first four capuchin monkeeys were received in 1974. In 1975, we acquired Bubi, then 17 years
old, and imported eleven more animals, of whom one female, Teufel, was clearly dominant. At first
we kept all the capuchins in one group, but we soon found that this was not feasible. Repeatedly,
certain individuals would get bitten and be driven off, so that it seemed impossible to maintain a
single large group. Six capuchins acquired in 1977 did not get along either, and could not be kept
together. We observed, however, that the quarreling animals would help each other, and were loud
in support of each other even though screen partitions, when the adversary was a newly introduced
animal - or in the case of the newly introduced, if the adversary was an already acclimated
individual. Apparently the capuchins in their own shipment were more familiar to them than the
others.
We utilized this situation to construct a large capuchin group. We put two displaced newly
imported animals with a female of the original group. Then, as the balance of social relations
seemed to dictate, we would add either settled or newly imported individuals, and were thus able to
maintain a more or less stable group.
Before we discuss our own research finding in detail, it should be emphasized that even today, a
preference for individuals of the same transport class is still perceptible, though less pronounced
than formerly. Likewise, our procedure of constructing balanced groups is still the same. Any
rejected individuals are placed in association with others that are less familiar, common with still
other familiar ones. On the basis of experiments of recent years, we can now predict with fair
confidence what will happen in the new combination.
It is a conspicuous trait of our capuchin monkeys that the females court the males. They approach
the selected male with eyebrows raised high and beckon him to follow them with gestures and
typical sounds. This is often a dubious enterprise, as the males may not be interested in the
courting females. But when it is successful,the males will respond with the same mime and gesture,
following the females and mating with them. Mating is commonly preceded by prolonged mutual
handling.
Newborn capuchins are quite helpless and for the first three weeks they remain more or less
motionless, crosswise on their mother's back. Their only activities are nursing, looking around,
scratching, climbing on the mother, and standing up on her. Nevertheless, capuchins only three
weeks old will climb on the backs of conspecifics resting together with the mother, but these others
will not yet carry them.
From the second month of life -- the young are now mostly borne lengthwise to the body, and are
themselves more active -- we regularly see them carried by other individuals, "friends" of the
mother (elder siblings, female or male). In the second month of life, the young begin to sit beside
the mother. By the end of this month they are alone regularly. Independent climbing and eating of
solid food are now seen for the first time. The juveniles actively begin to make contact with other
conspecifics in the third month. The close bond with the mother continues, independenly of
increasing maturity, until the end of six months of life; for sleeping and for safety, the young keep
returning to the mother's back. They are also occasionally nursed as late as the eleventh month.
Now if we consider the relations of to the young with other group members, we find that owing to
their helplessness and constant dependance on the mother, as we might except, capuchin babies are
at first merely "recipients" of social contacts. In the first months, siblings, especially sisters, are
particularly interested in the little capuchin. In the third month, the youngsters themselves seek
contact with their siblings. At four months, they become attractive to other young ones, whose
company they themselves will seek out deliberately in the fifth month. From that point on, even
adult males will take an interest in the adolescents. As a rule, one particular male will take up
relations with a particular youngster. This male need not be the father; as a rule, according to our
observations, it will be the mother's " friend." then, in the sixth month of life, the youngster will
seek contact with just this male. In this same month, for the first time, the young capuchins
themselves will find additional social partners, who will be group members a year older, and not
related.
An especially remarkable feature of capuchin groups is that there are no rankings such as we find
among many Old World primates. As we have noted before, the group depends entirely on a
balance of social relationships. In each capuchin group, there is one dominant male and one
dominant female. The dominant male isolates himself from the rest of the group. Nonetheless, all
other group members are especially interested in contact with him. The dominant female also seeks
to maintain distance from the others. Her object is to build up special relationships with the
dominant male and disperse any others who approach him.
The dominant capuchin male, however, does not police or "supervise" the group; unlike the alpha
(highest-ranking) male of the macaques, who exerts an influence on all relationships, and
composes differences, he has little influence over group events. However, duties definitely devolve
upon him in defending the group against conspecifics. Accordingly, the respective dominant males
will sit on the outskirts of the group. The criteron of superiority is obviously not physical strength;
rather, what is important is feeling superior and "being regarded as" superior. Dominant males go
about with no fears of others, do not give ground in danger, and do not respond to threatening by
others.
The dominant female has no such paramount position. She is the female who decides all disputes
in her favor. In contradistinction to the great popularity of the dominant male, other animals tend
to avoid her. Our observations indicate that females too must feel superior in order to dominate.
Each dominant female seeks to secure the dominant male to herself alone. She will threaten
females who court "her" male. Only when the courting female has succeeded in getting the
dominant male to pursue her will this threatening begin. It is our impression that dominant
females seek to build up a mating relationship, but, because of the indifference of the dominant
male, they do not succeed.
Besides the presence of the two dominant individuals, we soon noticed that a capuchin group is
divided into several subgroups. In our colony, at first we observed only subgroups based on
one-to-one relationships. These were and are still today very stable. If an individual enters into
several one-to-one relationships at the same time, larger subgroups grow up. Eventually, one
individual comes to be so esteemed as a social partner that several partners are recruited through
one-to-one relationships. We have been able to observe several forms of such relationships in the
past. One-to-one relationships may be based on common social experience (pursuing or being
pursued) or on real friendships. These alone are highly stable.
Augmentation of the groups by additional births has shown us that young grow into their mother's
subgroup and become members of that subgroup. Kinship thus has special importance. Examining
individual social partners more closely, we find that females are prone to maintain contact with
females and males with males. These preferences become more pronounced with advancing age.
However, they can be detected even at the age of six months. Social contacts among males and
among juveniles, or between males and juveniles, are primarily play contacts. Males and juveniles
will also play with males and juveniles of other subgroups. Fighting games between males are
based on one-to-one relationships, where one individual can play with two others at the same time.
When two individuals exhibit the same behavior and play with different partners at a given time,
larger play groups may be formed.
In addition to this form of play, we also find what we call the "free-for-all," sometimes organized
in the evening hours by our strongest male, Don. He will hop about on the floor with outstretched
arms and be attacked by more or less all of the juveniles, or he will attack them himself. When he,
a heavy, full-grown capuchin male, jumps up and down on a one-year-old several times, the
observer may get the impression that the youngster is being abused. The young capuchin himself
appears to think otherwise. Once he has managed with difficulty to escape from Don, he will spring
at Don once more as if to recommence the game. The evening "free-for-all," with often more than
ten participants, is one of the most impressive shows put on by the capuchins.
Whereas males, then, mostly engage in play, females engage in other social contacts. They prefer
mutual grooming and close seated contact with other females. Grooming between females of
different subgroups is very rarely observed. We have learned repeatedly that even small capuchin
females are more inclined to sit together and groom each other than are young males. They do
indeed often play, but the sex differences are apparent by the end of the first six months of life.
According to our observations so far, kinship relationships are maintained throughout life. As a
result, even the newborn capuchin has a special built-in relationship not only with its siblings but
also with its grandmothers, its uncles, and its aunts.
The newborn is in their company more often than in that of other group membersof the same age.
Kinship, age, and sex determine the network of relationships of the individual capuchin. We are
indebted to our male capuchins, especially Bubi, for the interpretation of a cry seldom heard in
everyday capuchin experience. We have referred to it as the cry of greeting. Both Angelo Nolte's
famous Pablo and our Bubi use it especially in greeting familiar or attractive persons. We now
know what this utterance means. It is commmonly heard when, after some separation, males have
their first opportunity for physical contact.
Simultaneously with the loud cry of greeting, we observed that they touch each other's bodies and
erect sex organs. Females too may participate in this greeting. We can induce such an outcry
artificially by giving two groups with no screen contact access to neighboring cages. Evidently mere
visual contact has a very special quality.
Capuchins exhibit certain innate behavior patterns that were observed thirty years ago by the
above mentioned Munster zoologist Angela Nolte, again in the case of Pablo. In eating, they will
perform the maneuver of "making a table"; that is, they place their lower arms close together to
intercept any morsels that may be dropped. They crack nuts by impact, lay the head back when
squeezing fruits, and will rub fragrances all over the body. Their handling of tools has also been
described by her in detail. The capuchins in our colony daily confirm Angela Nolte's
interpretations of the behavior patterns she first observed and described . She is rightly considered
the pioneer in laboratory researches on South American monkeys.