If the Rev. Jerry Falwell were to give up on humanity and assemble a
congregation of creatures, the handful that would qualify as truly
blessed would include the black vulture, the California mouse, the sea
horse, some termites and a wingless cockroach. Of all God's creatures
great and small, these few make up most of those that can claim,
without fear of eternal damnation, to be monogamous.

"True monogamy is rare," Olivia Judson writes in her whimsical,
irreverent and illuminating book, "Dr. Tatiana's Sex Advice to All Creation."
"So rare that it is one of the most deviant behaviors in biology."
Judson is a British, Stanford-educated evolutionary biologist whose
lighthearted view of the natural world is not unlike that of Gary
Larson, the cartoonist who imagines an animal kingdom inhabited by
creatures that are self-aware. Judson's clever device is to pose as
Tatiana, a saucy "sexpert" who answers letters from concerned and
curious creatures.

One of the aforementioned monogamists, a black vulture from Louisiana,
pens this note: "My husband and I have been faithfully married for
years, and we are shocked by what we read in your columns. . . . We
suggest you champion fidelity or shut up."

Tatiana's tart retort: "Remember: revulsion is in the belly of the
beholder. And if I may say so, gorging on carrion is considered revolting in
some circles."

Tatiana's essential message is one of tolerance, of being open to all
the wonders of the natural world. "Beyond the basic fact that males
make sperm and females make eggs," she writes, "there are no rules,
not even in what appear to be the most stereotypical gender-related
areas."

Tatiana cites countless examples of how creatures reproduce, forming
what she calls a "fabulous diversity."

There is, for instance, the European giant garden slug. A pair mates
for hours while suspended upside down on a string of mucus. Male
marine iguanas, to reduce the time it takes to release sperm,
masturbate when a female passes by. (Unlike most male creatures, they have
the advantage of sporting two penises.) The female midge (a tiny fly)
punctures the male's head and drinks up his innards as an apres-sex
snack.

Such feasting isn't restricted to the sex act: A sand shark fetus, as
Tatiana puts it, "gobbles up its embryonic brothers and sisters while
they are in the womb." (The technical term, charming it is not, is
intrauterine cannibalism.)

With great ease, Tatiana jumps from creature to creature to illustrate
her points, which include succinct and fascinating observations on
pleasure, rape, incest, self-fertilization and homosexuality. Among
those creatures that don't discriminate by gender in their sexual habits
are bonobos (or pygmy chimps), dolphins, razorbills (similar to
puffins) and small penguins that live in Antarctica.

Judson's habit of having Tatiana address "girls" and "boys" wears a
little thin, and she's too quick to cart out cliches and puns that would
make any creature groan. What serves her best are her flashes of
British understatement and a writing peppered with decidedly
nonscientific terminology such as "jiggery-pokery," "argy-bargy" and,
perhaps least Darwinian of all, "wankers."

As a final treat, Judson includes dozens of pages of small-print notes
and a bibliography. These show the breadth and depth of her scientific
research and hint at a wild, little-known world that researchers like
her are trying to understand. Somewhere out there, someone is studying
"copulatory plugs and paternity assurance in the nematode
Caenorhabditis elegans."

It may not sound too sexy, but who's to judge?