Gorillas have been caught on camera for the first time performing face-to-face intercourse. Humans and bonobos were the only primates thought to mate in this manner. And while researchers have observed wild gorillas engaged in such an act, it had never been photographed. "Our current knowledge of wild western gorillas is very limited, and this report provides information on various aspects of their sexual behavior," said Thomas Breuer of the Max Planck Institute for Evolutionary Anthropology. "It is fascinating to see similarities between gorilla and human sexual behavior demonstrated by our observation."