Museum 'Outs' Gay Animals

From male killer whales that ride the dorsal fin of another male to female bonobos that rub their genitals together, the animal kingdom tolerates all kinds of lifestyles, LiveScience.com reports.

A first-ever museum display, "Against Nature?," which opened last month at the University of Oslo's Natural History Museum in Norway, presents 51 species of animals exhibiting homosexuality.

"Homosexuality has been observed in more than 1,500 species, and the phenomenon has been well described for 500 of them," said Petter Bockman, project coordinator of the exhibition.

"I think to some extent people don't think it's important because we went through all this time period in sociobiology where everything had to be tied to reproduction and reproductive success," said Linda Wolfe, who heads the Department of Anthropology at East Carolina University. "If it doesn't have [something to do] with reproduction it's not important."

However, species continuation may not always be the ultimate goal, as many animals, including humans, engage in sexual activities more than is necessary for reproduction.

"You can make up all kinds of stories: Oh it's for dominance, it's for this, it's for that, but when it comes down to the bottom I think it's just for sexual pleasure," Wolfe told LiveScience.

Conversely, some argue that homosexual sex could have a bigger natural cause than just pure pleasure: namely evolutionary benefits.

Copulation could be used for alliance and protection among animals of the same sex. In situations when a species is mostly bisexual, homosexual relationships allow an animal to join a pack.

"In bonobos for instance, strict heterosexual individuals would not be able to make friends in the flock and thus never be able to breed," Bockman told LiveScience. "In some bird species that bond for life, homosexual pairs raise young. If they are females, a male may fertilize their eggs. If they are males, a solitary female may mate with them and deposit her eggs in their nest."