Ken Allen, an orangutan of the San Diego Zoo, became world famous in the 1980s for multiple escapes from his enclosures. He was nicknamed "the hairy Houdini" and was the subject of a fan club, T-shirts, bumper stickers and a song titled "The Ballad of Ken Allen". Galdikas reported that her cook was sexually assaulted by a captive male orangutan. The ape may have suffered from a skewed species identity and forced copulation is a standard mating strategy for low-ranking male orangutans.