Adult gorillas lack hair on the fingers, the soles of the hands and feet, and armpits. Hair is sparse on the upper chest, especially on older males. The skin of a gorilla is dark and covered with black to reddish-brown hair. As the animals mature, the hair turns gray. Males acquire silver-gray saddles across their backs and upper thighs at sexual maturity, earning them the name silverback.
Newborns initially have pinkish-gray skin which quickly darkens.
They frequently have a white rump patch until a few years old. E. Learning capacity. All great apes exhibit a capacity for complex learning. In behavioral research facilities, some gorillas have learned sign language and formed very simple sentences to communicate with people. Chimpanzees have been observed creating tools from their environment and then using them to accomplish certain tasks such as probing for termites with sticks or gathering water for drinking with crumpled leaves.