Chimpanzees, gorillas, and orangutans are all considered great apes. Of the three, chimpanzees are the most closely related to humans. Chimpanzees and humans share 98 percent of the same genetic makeup.
In addition, the two groups share many social and psychological traits. Researchers have documented chimpanzees making and using tools, expressing complex emotions, forming bonds and friendships, and communicating using sign language.
An average chimpanzee stands 5 feet (1.5 meters) tall and weighs about 150 pounds (68 kilograms). Since its arms are longer than its legs, a chimpanzee walks on the ground using the soles of its feet and the knuckles of its hands.