Summary
The
colobus monkey cannot be easily put into any one category when describing
its social system and social relationships. The reason for this is
the great variety of environments that they inhabit and the different pressures
that result from this. The following pressures seem to be most important
and determine what type of organization they exhibit:
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Food
Distribution--Food that is superabundant and unpredictable cannot be
defended. Consequently, colobus monkeys living in areas with this
type of food distribution live in home ranges. Colobus monkeys living
in areas with predictable, defensible food sources tend to be territorial.
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Predation
Pressure--Those colobus monkeys suffering from high predation pressure,
particularly the red colobus, need to live in large groups to protect themselves
from attack. Those living in the absence of predation pressure tend
toward smaller groups, sometimes one male units.
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Type
of Kin Group--Colobus monkeys organized in matrilineal kin groups often
are territorial and polygynous, because it is easier for a male to maintain
a territory and a harem when the females are closely bonded. Patrilineal
kin groups show no territories or harems, because it would be too difficult
to defend females who are not bonded and who will not necessarily stay
in a territory. These types of kin groups may be the result of the
specific environmental pressures, rather than the cause of social spacing
or mating systems.