Mountain Gorilla
Few animals have sparked the imagination of man
as much as the gorilla, the largest of the living primates and the
last member of the ape family known to science. Most gorillas live
in inaccessible regions in various dense forests in tropical Africa,
and only in the last 30 years have scientists learned details of their
life in the wild.
A chain of eight volcanoes known as the Virunga Volcanoes runs
through a western section of the Rift Valley, forming part of the
border between Uganda, Democratic Republic of Congo (formerly Zaire)
and Rwanda. These spectacular mountains and the nearby Bwindi Impenetrable
National Park in Uganda are the last refuges of the most endangered
of the gorilla subspecies, the mountain gorilla. Only about 672
of these individuals remain.
Physical Characteristic
The gorilla is massive, with a short, thick trunk and broad chest
and shoulders. Its eyes and ears are dwarfed by its large head and
hairless, shiny black muzzle. Older males develop a crown of muscle
and hair that makes the head look even longer. The arms are longer
than the stubby legs. The fully adult male mountain gorilla is twice
as large as the female.
Habitat
The most serious threat to gorillas is habitat loss.
The rich volcanic soil of the Virungas is as highly valued as farming
land. In Rwanda, Uganda and Congo, a regional conservation program
stressing the importance of maintaining the virgin forest watershed
and the need to habituate some groups of gorillas for tourist visits
has helped ease encroachment.
Behavior
The gorilla is shy and retiring rather than ferocious.
It usually seeks no trouble unless harassed. However, the dominant
male will valiantly defend its family group if threatened. Family
groups are close-knit and may have up to 30 members, but even if smaller,
the group usually consists of at least one older male, one or more
females and a few juveniles.
Gorillas have strong attachments to members of their own group.
Even when groups meet and mingle and then subsequently part, each
animal tends to remain with its respective unit. The silverback
(adult male gorillas) named for the silvery gray hairs on its back
normally leads each group, serving as its chief protector and defender.
Gorillas continually wander through their home ranges of 10 to 15
square miles, feeding and resting throughout the day. Because gorillas
are nomadic, they build new nests each day at dusk, constructing
them of bent branches in a tree or of grasses on the ground.
A group's hierarchy, ritualized behavior and bluff charges between
males prevents conflict among and between groups. Gorillas scream,
grab foliage and stuff it in their mouths, stand erect on their
hind legs, tear up and throw plants, drum on the chest with hands
or fists, stamp their feet, strike the ground with the palms of
their hands and gallop in a mock attack on all fours.
Diet
Animals of this size need a lot of food, and the
vegetarian gorilla is no exception. Although they eat a variety of
plants, favorites include wild celery, bamboo, thistles, stinging
nettles, bedstraw and certain fruit. These plants seem to provide
sufficient moisture so that gorillas do not need water.
Caring for the Young
Mountain gorillas have a slow rate of reproduction.
Females give birth for the first time at about age 10 and will have
more offspring every three or four years. A male reaches sexual maturity
between 12 and 15 years, when he is in charge of his own group. Able
to conceive for only about three days each month, the female produces
a single young and in rare cases twins.
Newborn gorillas are weak and tiny, weighing in at about 4 pounds.
Their movements are as awkward as those of human infants, but their
development is roughly twice as fast. At 3 or 4 months, the gorilla
infant can sit upright and can stand with support soon after. It
suckles regularly for about a year and is gradually weaned at about
31/2 years, when it becomes more independent.
Predators
The gorilla's only known enemies are leopards and
humans. Crocodiles are potentially dangerous to lowland gorillas.
In western Africa, gorillas are commonly hunted for meat or in retaliation
for crop raiding, but in eastern Africa they have been the victims
of snares and traps set for antelope and other animals. Poachers have
also destroyed entire family groups in their attempts to capture infant
gorillas for zoos, while others are killed to sell their heads and
hands as trophies.
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