MonkeyPro Information Repository
Topic: Primate Social Systems
Richard Wrangham stated that social systems of non-human primates are best
classified by the amount of movement by females occurring between groups. He
proposed four categories:
- Female transfer systems – females move away from the group in which they
were born. Females of a group will not be closely related whereas males will
have remained with their natal groups, and this close association may be
influential in social behavior. The groups formed are generally quite small.
This organization can be seen in chimpanzees, where the males, who are
typically related, will cooperate in defense of the group's territory. Among
New World Monkeys, spider monkeys and muriquis use this system.
Japanese Macaques bathe together in Jigokudani Hot Spring
- Male transfer systems – while the females remain in their natal groups,
the males will emigrate as adolescents. Polygynous
and multi-male societies are classed in this category. Group sizes are
usually larger. This system is common among the
capuchin monkeys and
- Monogamous species – a male–female bond, sometimes accompanied by a
juvenile offspring. There is shared responsibility of parental care and
territorial defense. The offspring leaves the parents' territory during
Gibbons essentially use this system, although "monogamy" in this context
does not necessarily mean absolute sexual fidelity.
- Solitary species – often males who defend territories that include the
home ranges of several females. This type of organization is found in the
Orangutans/a> do not defend their territory but effectively have this
Other systems are known to occur as well. For example, with
howler monkeys both the males and females typically transfer from their
natal group on reaching sexual maturity, resulting in groups in which neither
the males nor females are typically related. Some prosimians, colobine
callitrichid monkeys use this system.
Chimpanzees are social animals.
Primatologist Jane Goodall, who studied in the Gombe Stream National Park,
noted fission-fusion societies in chimpanzees. There is
fission where the main group splits up to forage during the day,
then fusion when the group returns at night to sleep as a group. This
social structure can also be observed in the Hamadryas Baboon, spider monkeys
and the Bonobo. The Gelada has a similar social structure in which many smaller
groups come together to form temporary herds of up to 600 monkeys.
These social systems are affected by three main ecological factors:
distribution of resources, group size and predation.Within a social group there
is a balance between cooperation and competition. Cooperative behaviors include
social grooming (removing skin parasites and cleaning wounds), food sharing, and
collective defense against predators or of a territory. Aggressive behaviors
often signal competition for availability of food, sleeping sites or mates.
Aggression is also used in establishing dominance hierarchies.