Mountain Gorilla
Ecology
Mountain gorilla eating by stem peeling, a popular technique.
© Martin HARVEY / WWF-Canon
Physical Description
Gorillas are stocky animals with characteristically large hands, forearms that are much shorter than the upper arm, broad chests and shoulders and black, hairless faces. Their eyes are small and close together while the nostrils are large and prominent. The mountain gorilla has longer hair than the lowland subspecies, but slightly shorter arms. Adult males grow a patch of silver hair on their back and hips which has earned them the name 'silverback'. Mountain gorillas are generally larger than other subspecies. On average, adult males weigh 350 pounds and adult females weigh 216 pounds.
Diet
Gorillas are mainly herbivorous; their staple foods are pith, shoots and leaves. Fruits are also an important component of their diet based on seasonal availability. In drier months, when fruits are scarcer, gorillas supplement their diet with leaves, bark and rotten wood. The consumption of invertebrates, mainly termites and weaver ants is frequent, although it varies significantly across sites.
Reproduction
Females become sexually mature at seven or eight years old but do not start breeding until several years later. Males mature later than females and few before the age of 15.
High infant mortality, a long gestation (eight and a half months), a tendency to single births and a prolonged period of maternal care mean that, on average, only one baby is reared in a four to six year period. Females generally give birth to only three or four surviving young during their reproductive life.
Social Structure
A group of mountain gorillas usually consists of a single dominant silverback male, three adult females and four or five offspring. There is an overlap in group territories and the silverback generally defends his group rather than his territory.
Mountain gorillas are found at high altitudes (2,500-4,000 m) in montane forests, as well as bamboo forests. They have thicker and more fur than other great apes because of their unique mountain habitat where temperatures drop below freezing and there is frequent rain. Mountain gorillas climb to the tops of the mountains for a few days, but are forced to return to the bottom as a result of the freezing temperatures. As their habitat is cultivated mountain gorillas are being forced to stay at the tops of the mountains for longer than they can withstand the cold air.
