Like humans, female gorillas are pregnant for nine months and usually give birth to only one infant at a time. Newborn gorillas weigh about 4 lbs. (1.8 kg). From the time they're about 4 months to 2 or 3 years old, young gorillas ride on their mothers' backs as a form of transportation. At around 7 to 10 years, the young gorilla will become mature enough to have its own offspring. At this point, the gorilla will leave its mother's group to find a mate. Gorillas can live around 35 years in the wild and more than 50 years in zoos, according to the WWF. Classification/taxonomy