Nigeria, Central African Republic, Equatorial Guinea, Gaboon, Republic of Congo, Angola, and Democratic Republic of Congo.
Western gorillas are exceptionally large and powerful primates. Gorillas have dark brown to black fur and black skin. Dominant adult males, called silverbacks, have a prominent sagittal crest and striking silver coloration from their shoulders to rump. Males and females are sexually dimorphic, with males weighing up to 181 kg (400 lb) in the wild and 227 kg (500 lb) in captivity and measuring, on average, 1700 mm, while females weigh between 72 and 98 kg (159 and 216 lb) and measure, on average, 1500 mm (4.92 ft). Hands are proportionately large with nails on all digits and very large thumbs. Limbs are plantigrade and pentadactyl. The main locomotion pattern of gorillas is quadrupedal knuckle-walking although they do climb and spend limited amounts of time standing bipedally.