Anyone who doesn't realize that the intimate details of penguin family life are a hot political topic must have spent the last couple of years on an ice floe. First was the proliferation of same-sex penguin couples, most notably in Manhattan's Central Park Zoo. Roy and Silo, male chinstrap penguins, attracted international attention when they paid no attention to females in their enclosure, instead building a nest together and attempting to incubate a rock. After a sympathetic keeper gave the pair an egg, a chick called Tango emerged, who became the star of a children's book And Tango Makes Three.

The book — and the story — was embraced by gay-rights activists, who claim it illustrates the normalcy of homosexual families, an assertion hotly contested by conservatives. When, in a dramatic turn, the dapper couple split, with Silo taking up with Scrappy, a female from (where else?) California, right-wing website WorldNetDaily gloated over the break-up. The site predicted that the subject would be “dropped from the media ‘A list’ faster than you can swallow a smelt”.

On the contrary, last summer, the French documentary March of the Penguins became an unexpected box-office hit, and the penguin wars heated up. The film depicts the travails of emperor penguins as they migrate in subzero temperatures from the Antarctic ocean to their breeding grounds 70 miles away, mate, raise their impossibly adorable chicks, and return to sea. Perhaps because father penguins take a major role in child-rearing, spending weeks without food while guarding the egg and chick, the film also became a flashpoint for debates about family values. Conservative columnists praised the penguins' fidelity and sacrifice. Some went further and claimed the birds' behaviour upheld ideas about ‘intelligent design’. Meanwhile, liberals scoffed at the idea that the penguins’ lives of arduous deprivation represented the work of a creator; columnist Ellen Goodman observed, “if that is intelligent design, the big guy has quite the sense of humour”.

Penguin behaviour is fuelling debates about monogamy. Credit: © WARNER BROS. PICTURES 2005

Yet in the zeal for snappy headlines, some important points were overlooked. First, Roy and Silo are hardly the only same-sex couple either among penguins or in the animal kingdom; scientists are increasingly recognizing such behaviour in a wide range of species, from sheep to gulls. Its significance lies not in its ability to answer the question of whether homosexuality is natural, much less whether gay marriage or adoption should be legal, but in the insight it offers into what sex means. Those unfamiliar with the lives of animals in the wild often assume that sex occurs in a brisk businesslike fashion, solely for procreation. In fact, sex often achieves much more; in bonobos, highly social relatives of the chimpanzee, sex can defuse tense situations, and it occurs between members of the same sex, between adults and juveniles, and when conception is highly unlikely.

A far more interesting question than whether Roy and Silo vindicated the right or left wing is why we see pairings such as theirs in some species and not in others. Why in penguins and not in peacocks? Selection for pair bonds between males and females is likely to be the key starting point. Penguins as a group are monogamous, because it takes both parents to rear the chick, so the evolutionary seeds for seeking out a single mate are far more likely to take root in them than in the flamboyant peafowl, where a single mother can raise a brood alone.

Moreover, mate fidelity varies among penguins, with the emperors, rather ironically, showing high rates of partner switching between seasons (something the film notes but religious commentators conveniently ignore). Scientists speculate that the environmental constraints on breeding are so severe for the emperor penguins that they cannot afford the luxury of searching out the same partner they had the year before.

Conservative journalist Warren Throckmorton commented, “About the only thing we can say from the Roy, Silo and Scrappy love triangle is that sexuality in animals is flexible, context-driven and influenced by factors we do not fully understand”. But this is actually a rather profound conclusion, suggesting that animal sex could be far more complicated than a quick instinct-driven coupling. In other words, animal sex can be a lot like human sex, which may not be what Throckmorton intended to say.

Tom Turnipseed, writing for the website Zmag.org, suggested that the real message lies in the penguins' “cooperating with one another and sacrificing their own lives and individual gain for the common good and survival of their own kind” — behaviour that executives at Enron, the US energy company involved in an infamous corruption scandal, should have emulated. Other reviews also allude to this supposedly altruistic behaviour and the “inexplicable love” shown.

Were we watching the same film? In fact, the penguins are perfect little darwinians, selfish as can be. 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.

But if the penguins simply needed to save the species, surely any chick would do, and feeding the nearest hungry beak would save all that tramping through the snow searching for one's special little one. Why bother? Evolution supplies the answer: only scrupulous discrimination of your own kin will perpetuate one's genes. How the penguins manage such sophisticated feats is a fascinating area of study, one that will yield much more than a consideration of whether they are good role models for monogamy.

If we use animals as poster children for ideology, we not only end up in meaningless arguments over whose examples are more significant (cannibalistic mantids or promiscuous bonobos?), we risk losing sight of what is truly interesting and important about their behaviour. What the executives at Enron are supposed to learn is another story.