Basic Facts About Gorillas
Closely linked by DNA, gorillas (family Hominidae) are one
of the four species of great apes that are the closest living relatives of
humans – the other three are chimpanzees, bonobos and orangutans. Great apes
are different from monkeys for a variety of reasons: they are larger, walk
upright for a longer period of time, don’t have tails and have much larger,
more developed brains.
There are four subspecies of gorillas: the eastern lowland
or Grauer’s gorilla (Gorilla beringei graueri); the mountain gorilla (Gorilla
beringei beringei); the western lowland gorilla (Gorilla gorilla gorilla); and
the Cross River gorilla (Gorilla gorilla diehl).
Like all great apes, gorillas have arms that are longer than
their legs and tend to walk on all four limbs at certain times – a movement
that is called knuckle walking. Adult males are known as 'silverbacks' due to
the distinctive silver-colored hair on their backs.
Gorillas' appearances can vary based on sub-species, but for
the most part, the western subspecies tend to be brownish gray in color, while
the eastern and mountain gorillas tend to have a more blackish coat. Mountain
gorillas also have longer and thicker fur which is adapted to their colder
mountainous habitat. The three lowland subspecies of gorillas sport short, fine
hair. Eastern lowland gorillas are the largest of the four subspecies.
Diet
Gorillas are herbivores and eat leaves, shoots, roots, vines
and fruits.
Population
Eastern lowland gorilla numbers have rapidly declined to
below 5,000 today. Critically endangered, there are fewer than 300 Cross River
gorillas. Mountain gorillas, another endangered subspecies, number at around
700. A recent survey has shown that there are around 150,000-200,000 western
lowland gorillas.
Range
Eastern lowland gorillas are found in part of the eastern
Democratic Republic of Congo (DRC), Uganda and Rwanda, while mountain gorillas
are only found within the Virunga mountain region straddling the DRC, Rwanda
and Uganda borders, as well as the Bwindi Impenetrable National Park in Uganda.
Western lowland gorillas inhabit Cameroon, Nigeria, the Central African
Republic, the Republic of Congo, eastern DRC, Equatorial Guinea, Gabon and
Angola. Cross River gorillas are confined to a small region in Nigeria and
Cameroon.
Behavior
Gorillas are ground-dwelling and live in groups of 6-12 with
the oldest and largest silverback leading a family of females, their young and
younger males called blackbacks. The silverback makes the decisions on when his
group wakes up, eats, moves and rests for the night. Because he must protect his
family at all times, the silverback tends to be the most aggressive. In such
situations, he will beat his chest and charge at the perceived threat.
Gorillas are shy animals that are most active during the
day. At dusk, each gorilla constructs a ‘nest’ of leaves and plant material in
which it will sleep. Mothers usually share their nests with nursing infants.
Young males may leave their family groups as they become
older and either live as solitary silverbacks or create their own family
groups. The silverback has the exclusive rights to mate with the females in his
group.
Reproduction
Mating Season: Throughout the year.
Gestation: 8.5 months.
Litter size: 1 baby.
Gorilla infants are helpless at birth and weigh about 3-4
lbs. They learn to crawl at about 2 months and are walking by the time they are
around 8 or 9 months. Mother gorillas nurse their babies for about 3 years,
following which the young become more independent.
Threats
Gorillas are threatened by habitat loss due to increasing
human populations, poaching for the bushmeat trade and diseases like ebola.
Species that live in higher elevations, like mountain gorillas, are also
affected by climate change, which has the potential to impact gorillas directly
by altering their habitat, and indirectly by affecting agriculture yields in
nearby communities, which in turn puts more pressure on remaining habitat.
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