An uneasy mix of personal prejudice and intellectual anxiety has allowed science to be misused to justify a philosophy of prejudice towards the gay and lesbian communities around the globe.   The reasoning is that from a Darwinian perspective homosexuality seems to be a clear non-starter.  Only heterosexual relationships can be successful in evolutionary terms.  Anything else means that the genes (the component parts of the DNA) of the parties involved do not survive their death.  They cannot therefore influence the course of future evolution. The antithesis of this untested notion is that since homosexuality patently does exist, it must have an evolutionary advantage.  This notion is seldom voiced by such social conservatives.  The modern development of Darwinian Theory lays in currently accepted and developing genetic theories.  These stress the existence of ‘the selfish gene’.  Thus genes only create the machines called living organisms so as to ensure their (the genes) survival into the future at all costs.

A new book by Bruce Bagemihl called “Animal Exuberance: Animal Homosexuality and Natural Diversity” is effectively a compendium of animal homosexuality which profiles over 450 species.  Bagemihl spent 10 years searching carefully through the scientific literature.  He was unearthing documented cases of same sex encounters with apparent sexual significance.  He contacted scores of researchers to add detail not included in published papers. “Most are mammals and birds” says Bagemihl, “but perhaps only because I didn’t have time to go further”.  Most scientific readers take exception to one chapter in which he presents his own highly speculative alternatives to Darwinian evolutionary theory.  But a growing band of scientific researchers are openly welcoming his work.  It’s scale and depth are apparently unassailable “The beauty of the book is all that data,” says one evolutionary biologist from Oxford University.

Bagemihl stresses that animal homosexuality is not a single, uniform phenomenon.  His mission is to document its sheer diversity: “same sex behaviour in animals exhibits every conceivable variation”.  He documents, in about a quarter of cases, signs of  “affectionate” behaviour.  These activities do not involve direct genital contact but “nevertheless have clear sexual or erotic overtones”.  Male giraffes for instance indulge in prolonged bouts of affectionate “necking”, often followed by mounting and culminating in apparent organism.

“Nearly every type of same-sex activity among humans has its counterpart in animals” he concludes.   What seems undeniable is that homosexual behaviour is as “natural” as heterosexual behaviour.  Yet despite being so common it is far from common knowledge, even among scientists.  “Although the first reports of homosexual behaviour were published 75 years ago,” says Paul Vassey of Concordia University in Montreal; “virtually every major introductory text in primatology (the study of primate monkeys such as our closest relatives; chimpanzees and bonobos) fails to even mention its existence”.  On the face of it, sociobiological theory says it can’t happen”.  However another primatologist, Robin Dunbar, says “If you are looking for homosexual activity in vast quantities, forget humans, its bonobos (or pygmy chimpanzees) you want.  It’s scandalous.” He chuckles. “They’ll have sex with anyone never mind the sex or age”.  An observer doesn’t have to wait long to notice females locked into a face to face embrace all the better to indulge in mutual genital rubbing, or spy males glued together via open-mouthed kisses with plentiful mutual tongue stimulation. 

All this may represent the tip of the iceberg as the truth is that even in long term field studies of many species, sexual behaviour is rarely observed.  Heterosexual mating between cheetahs, for instance, has been recorded only five times in the wild.  To compound the difficulties, in many species, males and females look alike, at least to the human eye.  King penguins in Edinburgh Zoo at the beginning of the 1900′s went through a number of embarrassing name changes as their keepers realised that sexual behaviour is no fool proof clue to biological sex.

Currently the new DNA testing technology is exposing unconventional social set-ups among other identical looking birds.  A study of Roseate Terns in the USA has found that 12% of nests are tended by lesbian terns, who share in the incubation of 3 or 4 eggs – two is the norm for heterosexual couples.  The females fertilise their eggs through a quick fling with paired and breeding males, but many have remained faithful to another female through the five years of the on going study.  However as only one chick usually survives to adulthood it seems that one of the lesbian partners seems to have zero success in genetic terms.  But what if the birds are related?  The researchers are now using DNA fingerprinting to discover whether the partners in female pairs are sometimes mothers, daughters, aunts or nieces or sisters.  Could it be that the lesbian strategy isn’t second best at all?  “There is certainly more going on here than meets the eye” says one of the researchers cautiously.

Mac McCorry (with respect and thanks to New Scientist)