The
Circle of Life...
A great
deal of time and energy is invested in each offspring of the Western
Gorilla. Like humans, females ovulate throughout the year in
a monthly cycle. The dominant silverback in a troop mates with the
adult females, who reach sexual maturity between the ages of 9 and 12
years. Males reach sexual maturity between the ages of 10 and 13, but
females prefer to mate with older males. Mating usually occurs
dorsoventrally, but some cases of face-to-face mating have been seen
both in capitivity and, recently, in the wild. 4,7,15
After
a female gorilla becomes pregnant, the gestation period lasts
for about 8.5 months. Twins are a rare occurrence in Western Gorillas,
and females typically wait four years between births, so they can
properly care for each offspring while it grows and develops. About
half of gorilla infants will die before they become adults. Because of
these factors, the Western Gorilla experiences a very low rate of
population increase, if it increases at all. 9,18
A newborn weighs from 4 to 5 pounds and clings to
its mother constantly. The mother will nurse it for the firs
t 3 to 4
years of its life and, along with other adults in the group, teach it
what foods to eat, how to behave, and how to care for its own
offspring. Female gorillas show extreme affection with their young.
Mature males will fiercely protect the babies in their own groups,
since lone outside males have a tendency to commit infanticide when
attempting to take over another silverback's troop; however, males are
not affectionate and cuddly with their young. 3,4,7,15
After the
offspring reach sexual maturity, they will usually leave the group.
This helps increase genetic variation and decrease inbreeding. Females
will join another established group, while young males may attempt to
start their own group or will form a "bachelor group." As males mature,
they develop a silvery "saddle" across their back and upper thighs,
which distinguishes them as "silverbacks." In the wild, Western
Gorillas have a life span of 30 to 40 years, while they frequently live
up to 50 years in captivity. 3,4,7,15
However, there are currently many outside factors detrimentally
affecting the life spans within Africa's wild populations of Western
Gorillas. Learn more about these threats
here.
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designed by Arika Wussow, Last updated April 2008.
MultipleOrganisms.net
University
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t 3 to 4
years of its life and, along with other adults in the group, teach it
what foods to eat, how to behave, and how to care for its own
offspring. Female gorillas show extreme affection with their young.
Mature males will fiercely protect the babies in their own groups,
since lone outside males have a tendency to commit infanticide when
attempting to take over another silverback's troop; however, males are
not affectionate and cuddly with their young. 3,4,7,15