Video of a gorilla in a zoo who prefers to walk upright.

Click this link to see the video - National Geographic - Gorilla walking upright at Philadelphia Zoo

The male, originally born in St. Louis, has been in captivity for his entire life. Few remain in the wild, where the species is critically endangered. Stern says his walking style is more likely a personality quirk than a byproduct of life spent inside a zoo. More commonly, gorillas walk on all fours, using their knuckles to help support their weight.