Biological Exuberance: Animal Homosexuality and Natural Diversity.

Bruce Bagemihl talks about his new book--Biological Exuberance--and how it proves that sexuality in nature is "gay," "straight," and everything in between

"It's not natural!" That time-worn argument against homosexuality has been all but impossible to refute-until now. In his new book, Biological Exuberance: Animal Homosexuality and Natural Diversity (St. Martin's, $40), author Bruce Bagemihl portrays an animal kingdom that embraces a whole spectrum of sexual orientations. From female grizzly bears cooperating their cubs to trysting male lions fending off other envious males, the book paints a complex mosaic that resembles humanity.

"I'm not just a mirror of myself," says bagemihl, 36, a gay biologist who lives in Seattle. "I'm finding a mirror of the larger diversity that exists among animals and people."

Animals are not only capable of homosexuality and bisexuality, as many owners of domestic pets can verify. They are also capable, according to Bagemihl, of rape, "divorce," cannibalism, child abuse, "cross-dressing," and infidelity. "It's an expanded vision of what the natural world is all about," he says. "We're not alone in having a range of sexual behaviors. This is something that is all-encompassing."

Bagemihl says he didn't write the book because of his own sexual identity. "I'm a scientist who is gay," he says. "I can't separate the two. I wrote this as a scientist, but the implications for humans are enormous." Surprisingly, many of these findings existed when he began to research the book ten years ago. Bagemihl pored over arcane publications from around the world, some dating back to the mid 18th century. "I was surprised at the sheer number of species involved. The range of behavior, from same-sex cooperating to pair bonding [a couple-like arrangement] among some animals, including cheetahs, bottlenose dolphins, and silver gulls, can last temporarily or a lifetime."

The rather unscientific homophobia of scientists is largely what kept the data buried, Bagemihl says. "Over the years, some scientists have used double standards when observing sexual behavior in animals," he says. "If they couldn't tell the gender or genders of the animals involved, they would assume the pair were of opposite sexes. When observed, homosexuality has been dismissed as aberrant, unnatural, even criminal."

Homosexuality in nature was excused in many ways. "They said the animals were just practicing," Bagemihl says. "Or that [oral-genital stimulation] was for nutritional value. Or that they were only doing so because of the absence of the opposite sex in captivity."

At 751 pages and with photos and documentation of homosexual behavior in more than 450 species of mammals, birds, reptiles, and insects, Biological Exuberance brings the dusty facts to light as Bagemihl deconstructs the all-heterosexual Noah's Ark we've been sold.

"Courtship, sex, affection, gathering food, finding a home--they have all been observed among a range of partners, from heterosexual to homosexual to somewhere in between," Bagemihl says. "And there are some animals who don't have sex at all." Although he doesn't claim to know the motivations of animals, Bagemihl says he does know procreation is not always the driving force: "Same-sex couplings occur in the presence of the opposite sex, in and out of captivity, and in and out of mating season."

The more complicated the animal, the more sexually erratic--and less monogamous-it is likely to be. Mammals, for instance, may pair off but are more likely to have a range of mates. In what can be called a kind of genetic cross-dressing, the markings of some birds are distinctly close to the markings of the opposite sex of the species. "It's too simplistic to say they are taking on gender roles," the author says. "It's really much more complex. They alternate behavior. They are sharing."

Bagemihl says his own relationship has been influenced by his findings. "It's at the partnership end of the continuum," he says, chuckling. He's aware that the chaotic system in his book flies in the face of Darwin's neat and ordered food chain. "There's a lot of mystery. But we don't need to know why it all happens," Bagemihl says. "Just that it does and that it contributes to the whole."

Harrold is a Los Angeles-based freelance writer.