Not so long ago, any form of sexuality not leading to the conception of children was seen as, at best, wanton lust, or worse, a perversion. One by one, the taboos have fallen. The idea that it could be wrong to use contraception in order to separate sex from reproduction is now merely quaint. If some religions still teach that masturbation is "self-abuse," that just shows how out of touch they have become. Sodomy? That's all part of the joy of sex, recommended for couples seeking erotic variety. In many of the world's great cities, gays and lesbians can be open about their sexual preferences to an extent unimaginable a century ago. You can even do it in the U.S. Armed Forces, as long as you don't talk about it. Oral sex? Some objected to President Clinton' choice of place and partner, and others thought he should have been more honest about what he had done, but no one dared suggest that he was unfit to be President simply because he had taken part in a sexual activity that was, in many jurisdictions, a crime. But not every taboo has crumbled. Heard anyone chatting at parties lately about how good it is having sex with their dog? Probably not. Sex with animals is still definitely taboo. If Midas Dekkers, author of Dearest Pet, has got it right, this is not because of its rarity. Dekkers, a Dutch biologist and popular naturalist, has assembled a substantial body of evidence to show that humans have often thought of "love for animals" in ways that go beyond a pat and a hug, or a proper concern for the welfare of members of other species. His book has a wide range of illustrations, going back to a Swedish rock drawing from the Bronze Age of a man fucking a large quadruped of indeterminate species. There is a Greek vase from 520 BC showing a male figure having sex with a stag; a seventeenth-century Indian miniature of a deer mounting a woman; an eighteenth-century European engraving of an ecstatic nun coupling with a donkey, while other nuns look on, smiling; a nineteenth-century Persian painting of a soldier, also with a donkey; and, from the same period, a Japanese drawing of a woman enveloped by a giant octopus who appears to be sucking her cunt, as well as caressing her body with its many limbs. How much of this is fantasy, the King Kong-ish archetypes of an earlier age? In the 1940s, Kinsey asked twenty thousand Americans about their sexual behavior, and found that 8 percent of males and 3.5 percent of females stated that they had, at some time, had a sexual encounter with an animal. Among men living in rural areas, the figure shot up to 50 percent. Dekkers suggests that for young male farm hands, animals provided an outlet for sexual desires that could not be satisfied when girls were less willing to have sex before marriage. Based on twentieth-century court records in Austria where bestiality was regularly prosecuted, rural men are most likely to have vaginal intercourse with cows and calves, less frequently with mares, foals and goats and only rarely with sheep or pigs. They may also take advantage of the sucking reflex of calves to get them to do a blowjob. Women having sex with bulls or rams, on the other hand, seems to be more a matter of myth than reality. For three-quarters of the women who told Kinsey that they had had sexual contact with an animal, the animal involved was a dog, and actual sexual intercourse was rare. More commonly the woman limited themselves to touching and masturbating the animal, or having their genitals licked by it. Much depends, of course, on how the notion of a sexual relationship is defined. Zoologist Desmond Morris has carried out research confirming the commonplace observation that girls are far more likely to be attracted to horses than boys, and he has suggested that "sitting with legs astride a rhythmically moving horse undoubtedly has a sexual undertone." Dekkers agrees, adding that "the horse is the ideal consolation for the great injustice done to girls by nature, of awakening sexually years before the boys in their class, who are still playing with their train sets . . . " The existence of sexual contact between humans and animals, and the potency of the taboo against it, displays the ambivalence of our relationship with animals. On the one hand, especially in the Judeo-Christian tradition — less so in the East — we have always seen ourselves as distinct from animals, and imagined that a wide, unbridgeable gulf separates us from them. Humans alone are made in the image of God. Only human beings have an immortal soul. In Genesis, God gives humans dominion over the animals. In the Renaissance idea of the Great Chain of Being, humans are halfway between the beasts and the angels. We are spiritual beings as well as physical beings. For Kant, humans have an inherent dignity that makes them ends in themselves, whereas animals are mere means to our ends. Today the language of human rights — rights that we attribute to all human beings but deny to all nonhuman animals — maintains this separation. On the other hand there are many ways in which we cannot help behaving just as animals do — or mammals, anyway — and sex is one of the most obvious ones. We copulate, as they do. They have penises and vaginas, as we do, and the fact that the vagina of a calf can be sexually satisfying to a man shows how similar these organs are. The taboo on sex with animals may, as I have already suggested, have originated as part of a broader rejection of non-reproductive sex. But the vehemence with which this prohibition continues to be held, its persistence while other non-reproductive sexual acts have become acceptable, suggests that there is another powerful force at work: our desire to differentiate ourselves, erotically and in every other way, from animals. Almost a century ago, when Freud had just published his groundbreaking Three Essays on Sexuality, the Viennese writer Otto Soyka published a fiery little volume called Beyond the Boundary of Morals. Never widely known, and now entirely forgotten, it was a polemic directed against the prohibition of "unnatural" sex like bestiality, homosexuality, fetishism and other non-reproductive acts. Soyka saw these prohibitions as futile and misguided attempts to limit the inexhaustible variety of human sexual desire. Only bestiality, he argued, should be illegal, and even then, only in so far as it shows cruelty towards an animal. Soyka's suggestion indicates one good reason why some of the acts described in Dekkers book are clearly wrong, and should remain crimes. Some men use hens as a sexual object, inserting their penis into the cloaca, an all-purpose channel for wastes and for the passage of the egg. This is usually fatal to the hen, and in some cases she will be deliberately decapitated just before ejaculation in order to intensify the convulsions of its sphincter. This is cruelty, clear and simple. (But is it worse for the hen than living for a year or more crowded with four or five other hens in barren wire cage so small that they can never stretch their wings, and then being stuffed into crates to be taken to the slaughterhouse, strung upside down on a conveyor belt and killed? If not, then it is no worse than what egg producers do to their hens all the time.) But sex with animals does not always involve cruelty. Who has not been at a social occasion disrupted by the household dog gripping the legs of a visitor and vigorously rubbing its penis against them? The host usually discourages such activities, but in private not everyone objects to being used by her or his dog in this way, and occasionally mutually satisfying activities may develop. Soyka would presumably have thought this within the range of human sexual variety. At a conference on great apes a few years ago, I spoke to a woman who had visited Camp Leakey, a rehabilitation center for captured orangutans in Borneo run by Birute Galdikas, sometimes referred to as "the Jane Goodall of orangutans" and the world's foremost authority on these great apes. At Camp Leakey, the orangutans are gradually acclimatised to the jungle, and as they get closer to complete independence, they are able to come and go as they please. While walking through the camp with Galdikas, my informant was suddenly seized by a large male orangutan, his intentions made obvious by his erect penis. Fighting off so powerful an animal was not an option, but Galdikas called to her companion not to be concerned, because the orangutan would not harm her, and adding, as further reassurance, that "they have a very small penis." As it happened, the orangutan lost interest before penetration took place, but the aspect of the story that struck me most forcefully was that in the eyes of someone who has lived much of her life with orangutans, to be seen by one of them as an object of sexual interest is not a cause for shock or horror. The potential violence of the orangutan's come-on may have been disturbing, but the fact that it was an orangutan making the advances was not. That may be because Galdikas understands very well that we are animals, indeed more specifically, we are great apes. This does not make sex across the species barrier normal, or natural, whatever those much-misused words may mean, but it does imply that it ceases to be an offence to our status and dignity as human beings.