Birds do it and bees do it. But according to a new and exhaustively researched work from St. Martin's Press, the animal kingdom d s it with much greater sexual diversity -- including homosexual, bisexual and nonreproductive sex -- than the scientific community and society at large have previously been willing to accept.

In fact, the most revolutionary conclusion in the book may be that "animals do it because they like it," said St. Martin's editor Michael Denneny. Representing more than 10 years of research and writing Biological Exuberance: Animal Homosexuality and Natural Diversity by Bruce Bagemihl is the first work to bring together more than two centuries of observation and "documentation of homosexual behavior in the natural world" for general readers, according to the author.

The book, Bagemihl told PW, "challenges traditional ideas in biology -- not all animal sexual behavior revolves around reproduction and procreation." In fact, Bagemihl claims that for centuries scientists have looked for ways to "explain" animal homosexuality. The book presents what he hopes will be a new scientific paradigm for the field -- he calls it "biological exuberance" -- described as an acceptance of the "extravagant excess and multiplicity of animal sexual behaviors."

His theory and documentation encompasses a whole range of "animal sexual and gender variance," including same-sex courtship, sexual encounters and homosexual parenting in more than 300 bird and mammal species worldwide, with many never-before-published illustrations and photographs.

And yes, said Bagemihl, the book is also meant to address "homophobia and bias in the scientific community," as well as to challenge social critics who, he says, often base their antigay positions on claims that homosexuality d sn't appear in nature. Bagemihl points to one study among many referring to "a lowering of moral standards among butterflies" to buttress his claims of a homophobic bias in the scientific documentation of animal homosexuality over the centuries.

The book offers a general discussion of the forms and history of observation of animal homosexuality as well as a reference section that details specific sexual behaviors for a wide range of mammals and birds. Elephants, apparently, have very little heterosexual activity, and in some bird species, said Denneny, 80% to 90% of their sexual activity is homosexual.

Bagemihl, who is also a linguist, has done extensive research into native and indigenous cultures to document their observations and general acceptance of animal homosexual behavior. "Sexual variance is not seen as outside of the natural order in native cultures," noted the author.

The book took a while to reach publication, said Denneny, who was the founder of St. Martin's Stonewall Inn Edition trade paperback line, in 1987, and is credited with being a pioneer in gay and lesbian trade book publishing. The book was also one of the 106 titles abruptly cut from HarperCollins's list in 1997. Denneny says he first saw the manuscript in 1994, during his short stay at Crown. After the book was cut from HarperCollins, "the agent, Natasha Kern, remembered my earlier interest," explained Denneny, who returned to St. Martin's in 1996. He hopes the book will have a "major impact" on scientific thinking like such seminal works as Edward Wilson's Sociobiology or John Boswell's Christianity, Social Tolerance and Homosexuality.

St. Martin's publicist Patricia Clough told PW that the book should be "review driven," and the house has no plans for an author tour. The first printing is 15,000. She said the book has been "well reviewed in the trade, and we're getting a lot of interest from academic and mainstream publications," including feature articles scheduled for the Advocate and Gear magazine.

"There's an insanity about sexuality in the country right now," Denneny observed. "We think it's likely that the book will generate some intellectual controversy."