A mature male gorilla can be over 6 feet tall and weigh 300 to 500 pounds. He can spread his arms 8 feet across and is as strong as 4 to 8 strong men. Adult female gorillas are about half the size of the males. Unlike us, their arms are longer and more muscular than their legs, and their big toes look like thumbs. Their bodies are covered by thick dark hair, except on the face, chest, underarms, palms of the hands and soles of the feet.
Gorillas normally walk by putting their feet flat and walking on the knuckles of their hands.
They can stand upright, but they don't do it very often. Gorillas do not beat their chests with their fists but with open cupped hands, making the familiar loud sound which can indicate aggression or excitement. Gorillas can live more than 50 years. They are helpless at birth and depend on their mothers for at least 3 years, and they usually stay in their family group as they grow up. Females mature at 10 to 12 years and males at 11 to 13 years.