The controversy came with the first daffodils in March, shortly after Peter Singer, the father of the animal rights movement, reviewed a reissue of the book ''Dearest Pet: On Bestiality'' (Verso), by the Dutch biologist Midas Dekkers, for Nerve, an online sex magazine. Three months have passed and still the sun has not set on the latest tempest surrounding Mr. Singer, the provocative author of ''Animal Liberation'' and a professor of bioethics at Princeton University's Center for Human Values.

Mr. Singer has received his share of human venom before this. Protesters have called him a Nazi for his view that in some cases infanticide and euthanasia are morally justifiable.

The furor this time concerns sex with animals.

In his review, titled ''Heavy Petting,'' Mr. Singer noted that almost all of the taboos on nonprocreative sex (taboos against homosexuality, oral sex, contraception and masturbation) have vanished. But one notable exception still stands: the taboo on sex with animals. ''Heard anyone chatting at parties lately about how good it is having sex with their dog?'' he asked. The persistence of the bestiality taboo, he wrote, reflects humans' ambivalence about animals. We know we are like them, but we think we are better, and so we want ''to differentiate ourselves, erotically and in every other way, from animals.''

Of course, the taboo does not prevent fantasies. Mr. Singer described the illustrations in Mr. Dekkers' book, including ''a 17th-century Indian miniature of a deer mounting a woman'' and a 19th-century Japanese drawing of a very busy giant octopus groping a woman. Nor is the taboo always effective in real life. Mr. Singer noted that some men have sex with hens, and certain people don't stop the family dog from making free with them, which occasionally leads to ''mutually satisfying activities.''