western lowland gorilla

Gorilla gorilla

Height:Males: 5'6"; Females: 4'6"
Weight:Males: up to 400 lbs; Females: up to 225 lbs
Geographic Distribution:Southeastern Nigeria, Cameroon, Gabon, Central African Republic, the Democratic Republic of the Congo and Equatorial Guinea
Habitat:Lowland tropical rainforests
Wild Diet:Leaves, herbs, shrubs, vines and other vegetation and fruits
Zoo Diet:Monkey chow, apples, oranges, bananas, grapes, sweet potatoes, carrots, celery, onions, green beans, spinach, kale, parsley and escarole or romaine lettuce
Status in the Wild:Gorillas are endangered in the wild and their range is shrinking, mainly due to degredation from agriculture, timber extraction, mining and climate change. There are also exceptionally high levels of hunting and disease-induced mortality.
Location:Tropic World: Africa

Gorillas are black to brown-gray in color and start to turn gray with age. They are sexually dimorphic (2 distinct gender forms): males weigh approximately twice as much as females. As they age, males get a broad silvery-white saddle on their back, from which the term "silverback" for dominant males was derived. Gorillas have large, muscular bodies and adult males are particularly massive in the chest and shoulders. Gorillas' arms are longer than their legs, a feature that enables them to walk comfortably on all fours. Although gorillas are well-adapted for ground dwelling, they have opposable thumbs and toes that allow them to grasp objects such as tree branches. Gorillas have prominent brown ridges and small ears. Their faces, feet, upper chest and the palms of their hands are hairless.

Gorillas are diurnal (active during the day), but typically rest during the hottest part of the day. The group is usually comprised of 1 silverback, or dominant male, adult females, maturing males, juveniles and infants; it is considered a polygynous society (1 male mates with multiple females in a single breeding season). Groups are called "troops." Troop sizes range from 2 - 35 members, averaging 10 - 20. The silverback male maintains the group's cohesion. Female gorillas leave their natal group at puberty to join other groups. Females are choosy about what troop to join. A powerful silverback who can effectively protect offspring from danger is preferred. The social ties between females are weak. Instead, the bond between each female and the silverback is what holds the group together. Aggression in gorillas is rare, and serious fights only occur when another silverback is encountered: then, the 2 males perform elaborate threat displays. These threats attempt to intimidate the rival male and possibly to attract some of the rival's females without having to engage in a physical confrontation. Displays include beating their chests and breaking vegetation as a defense against outsiders. They hoot to warn other troops to stay away. Grunts and barks keep the troop together, which is especially important during the troop's daily movements to new feeding sites. They may also communicate through facial expressions. When gorillas walk on all fours, they rest their weight on the knuckles of their hands, rather than putting their hands down flat on the ground. Gorillas will also climb around trees. At night they construct bowl-shaped nests out of leaves to sleep on. They are only shared by a mother and her nursing offspring. The number of nests in a given area are sometimes counted by scientists to estimate group populations.