Smithsonian.com

Female Laysan albatrosses. Photo credit: Eric VanderWerf

Female Laysan albatrosses, like the ones above, can pair bond for life; about a third of all bonded pairs in Hawaii are actually same-sex female couples. This pairing helps chicks because coupled birds are better at rearing young than single females, and it may also help colony stability by reducing the likelihood that paired males will be lured away from their mates.

Homosexuality is common throughout the animal kingdom, though lumping it all together in one category is probably oversimplifying the matter, say University of California at Riverside biologists Nathan Bailey and Marlene Zuk, who recently published a review of this subject in Trends in Ecology & Evolution.

“For example, male fruit flies may court other males because they are lacking a genes that enables them to discriminate between the sexes,” Bailey said in a statement. “But that is very different from male bottlenose dolphins, who engage in same-sex interactions to facilitate group bonding,” or the Laysan albatrosses.