Gorillas are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. The eponymous genus Gorilla is divided into two species: the eastern gorillas and the western gorillas (both critically endangered), and either four or five subspecies. They are the largest living primates. The DNA of gorillas is highly similar to that of humans, from 95–99% depending on what is counted, and they are the next closest living relatives to humans after the chimpanzees and bonobos.
A baby gorilla is called an infant, just like a human newborn. When gorillas are born, they weigh about 4 1/2 pounds. They develop quickly and are walking within six months. Gorillas remain with their mothers until they are between 4 and 6 years old. Because of these dependent youngsters, females give birth only once or twice a decade. Gorillas are not fully adult until they are about 10 years old. At this age, a gorilla is ready to reproduce, so it seeks a mate. Several females and their offspring live in groups led by one protective adult male, the silverback. Gorillas have a life span of about 50 years.