Penguins Come Out in Central Park

As gays go, Roy and Silo are not unusual. They cohabit, are affectionate in public and have been inseparable for years. Only their species marks them out. The New York pair are chinstrap penguins.

Every day at Manhattan's Central Park Zoo the two males entwine necks, vocalise to each other and have, er, sex. When offered female companionship, they decline.

Roy and Silo have even displayed urges to procreate, and once tried to hatch a rock. Finally their keeper, Rob Gramzay, gave them a fertile egg from another brood. Tango, their chick, was born later. The pair raised it lovingly. 'They did a great job,' admits Gramzay.

According to a study of the penguins released this weekend in the New York Times, Milou and Squawk - another pair of Central Park's male chinstraps - have started hanging out together, billing and bowing. At the New York Aquarium on Coney Island, Wendell and Cass - male blackfoot penguins - are a devoted couple.

But being gay is not just a New York penguin thing. In fact, scientists are discovering homosexuality everywhere they look. The lessons for humans are profound, say scientists.

Bruce Bagemihl, author of Biological Exuberance: Animal Homosexuality and Natural Diversity, says homosexual behaviour has been noted in more than 450 species and more often in wild animals than captive ones. The question is: why? Some researchers say it helps a species' survival. By not producing offspring, homosexuals can help to support relatives' young. 'That's a contribution to the gene pool,' says Professor Marlene Zuk of University of California, Riverside.

Sexuality means more than just procreation, says Zuk. 'In animals like the bonobo, you see expressions of sex outside the period when females are fertile. It means more than making babies.

'And why should we be surprised? People are animals.'