G. C. LEAVITT
assume that the closeness of inbreeding in a population gener-
ally declines with greater social complexity, the increasing size
of the breeding populations, and with geographical and social
mobility. On the other hand, we can observe inbreeding in-
duced by social class, religion, ethnicity and race in the sense
that these groupings tend to be exclusive.
A more exacting ecology of breeding patterns is offered by
Caldecott (1984, 1986a, 1986b) in his study of macaque mon-
keys. Dividing macaques species into two groups, Caldecott
(1986a) found that the availability of food in the environment is
related to the degree of inbreeding. Where food is scarce in the
environment females compete with males for limited food re-
sources. Consequently, the female foraging group will keep the
male population at a distance by encouraging males to compete
with one another for breeding females. The result is that fe-
males will share sex and food with only one dominant male.
The female competition with males is further reduced because
rivalry among males leads to a high male mortality. The re-
maining males will seek mates outside of their foraging group
of origin thus encouraging outbreeding.
Where food is abundant in the macaque environment males
are not compelled by females to compete for mates and they
remain part of the foraging group in more or less equal numbers
with females. During estrous, females in these groups mate
promiscuously engaging most, if not all of the adult males in
the group. Because there is no competition among males for
mates, males do not leave the group, which results in an inbred
population. Keeping males in the foraging group also provides
greater protection against predators and increases what Calde-
cott (1986a, 1986b) calls “paternalism”—because all the males
of the group are highly related to all other members of the troop,
adult males spend a great deal of their time caring for the
young.
Darwinian evolutionists who deal with complex social and
cultural behaviors commonly underestimate the influence that
the environment has on explaining behavior. We are so accus-
tomed to thinking of ourselves as free agents that it seldom
occurs to us that much of our behavior is often unconsciously
molded by the context within which we live. It did not occur to
Paleolithic hunters and gatherers, as they made the slow change
to agriculture, that the changing environment was dictating a
new way of life that would engulf most humans (Harris, 1977).
Though nearly universal, we would not imagine that agriculture
is an expression of genes.
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