Western Lowland Gorilla (male/silverback) at the Artis Royal Zoo (also known as Natura Artis Magistra), Amsterdam (Holland)
The Western Lowland Gorilla is one of two subspecies of the western gorilla that lives in montane, primary, and secondary forests and lowland swamps in central Africa in Angola, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Equatorial Guinea and Gabon. It is the gorilla usually found in Zoos. The Western Lowland Gorilla is the smallest subspecies of gorilla but nevertheless still a primate of exceptional size and strength. This species of gorillas exhibits pronounced sexual dimorphism. They possess no tails and have jet black skin along with coarse black hair that covers their entire body except for the face, ears, hands, and feet. The hair on the back and rump of males takes on a grey colouration and is also lost as they get progressively older. This colouration is the reason why older males are known as "silverbacks". Their hands are proportionately large with nails on all digits, similar to that of a humans, and very large thumbs. They have short muzzles, a prominent brow ridge, large nostrils, and small eyes and ears. Other features are large muscles in the jaw region along with broad and strong teeth. Western gorillas frequently stand upright, but walk in a hunched, quadrupedal fashion, with hands curled and knuckles touching the ground. This style of movement requires long arms, which works for western gorillas because the armspan of gorillas is larger than their standing height.