Gorillas, the largest living primates, stand up to 1.75 meters (68.8 in) tall on two feet, and have arm spans up to 2.75 meters (108 in). Adult male gorillas weigh between 135-275 kg (297-605 lb) and females, 70-140 kg (154-308 lb). In captivity, gorillas can weigh as much as 350 kg (770 lb). There are three subspecies within the genus, Gorilla gorilla, the western lowland gorilla; G. gorilla graueri, the eastern lowland gorilla; and G. gorilla beringei, the mountain gorilla.
Humans are unique among primates in that they alone practice obligatory bipedalism and their skeletons show distinctive adaptations for this form of locomotion. Humans' ability to regulate their body heat over long periods of heavy activity is also unique, as are their large brains that are highly developed organs that allow for technology, and diversity of culture and language. These qualities enable humans to travel over water, in the air, and into space.