There is a group of primates called the great apes. Great apes can stand on their hind legs. They are also very good with their hands and can use wooden sticks like tools. Great apes do not have tails. Gorillas are the largest of the great apes. Gorillas can weigh as much as 650 lb. (300kg). They live in groups of up to 20 animals. They eat in the trees and on the ground.