RIVERSIDE, February 27, 2007  –  They’re so cute, so cuddly, so adorable.  But penguins can also be controversial.

Roy and Silo, two male penguins in New York’s Central Park Zoo, had an affair that sparked a hot debate over the nature vs. nurture theory of homosexuality as the pair became the world’s best known “gay” penguins.

It is a topic that evolutionary biologist and University of California, Riverside, Professor Marlene Zuk will discuss tomorrow (Wednesday) evening in a lecture Penguin Sexual Politics in San Bernardino.

Roy and Silo built a nest together, incubated a rock, and when provided with a real egg were able to raise a female chick, Tango.

Gay-rights activists used the pair as proof that homosexuality occurs in nature.

But Professor Zuk, whose work focuses on behavioural ecology, and more specifically sexual selection, says there is a larger point.

“If we use animals as poster children for ideology, we not only end up in meaningless arguments over whose examples are more significant, but we also risk losing sight of what is truly interesting and important about their behaviour,” the professor wrote in an essay for the February 2006 issue of Nature magazine.

The importance, she says, is not whether or not a family headed by two male penguins proves that homosexuality is natural, but rather whether it offers a larger view of the purpose of sex.

Bonobo chimpanzees use sex not just for procreation, but also to defuse tense situations, even with members of the same sex, says Professor Zuk.  “Sexuality is a lot broader than what people would like to think ”

In the popular documentary, March of the Penguins, the filmmakers follow the lives of emperor penguins as they travel 70 miles in subzero temperatures to get to their nesting grounds. Once there, they mate and raise their chicks.

Conservatives hailed the film for its strong family values, pointing to the male penguins’ fidelity and sacrifice to guard the chicks.

But Professor Zuk says that kind of sacrifice is the way penguins guarantee the survival of their own genetic code.

“The Penguins are perfect little Darwinians, selfish as can be,” she wrote in the Nature article.  “No one seemed to question why the birds took such pains on their return to the breeding grounds to find their own mate, their own chick, in a crowd of thousands of look-alikes.

“It seemed human, after all, like sailors returning from war eagerly seeking their families among the throng on shore.”

Professor Zuk is the author of Sexual Selections: What We Can and Can’t Learn about Sex from Animals (University of California Press, 2002). Her next book, due for release in April, is Riddled with Life: Friendly Worms, Ladybug Sex and the Parasites that Make Us Who We Are.

■ Penguin Sexual Politics.  A lecture by Professor Marlene Zuk.  San Bernardino County Museum, 2024 Orange Tree Lane, Redlands, at 7.30pm.  Open to the public.  Admission is free.

■  Roy and Silo split as ‘an item’ almost two years ago, after seven years together.  Silo took a shine to Scrappy, a female from California.  As for Tango, she has a girl-friend, Tazuni …

■  Today (February 27), Gay New Zealand reported that researchers at University of Queensland, Australia, have found that female koalas indulge in lesbian "sex sessions", rejecting male suitors and attempting to mate with each other, sometimes up to five at a time.