SAN FRANCISCO — Giraffes like to neck. Lions can mate 50 times a day. Hornbills practice their own kind of bondage. And how do spiny African hedgehogs do it? Very carefully.
It's Valentine's Day at the San Francisco Zoo and the keepers are conducting their fifth annual Sex Tour. Sometimes romantic, often scientific, the tour is rated X--adults only, please.
"Animals do everything," says penguin keeper Jane Tollini, who first conceived of the tour for animal voyeurs. "Please don't go home and try some of these things. You may hurt yourself."
The Valentine tours, held over the weekend and today, are so popular they quickly sell out. Over the years, the idea has been copied by dozens of other zoos around the country, including the Los Angeles Zoo.
Riding around the San Francisco Zoo on the "Zebra Train," visitors learn about the reproductive behavior of various species, covering such themes as courtship, foreplay, domination, polygamy, monogamy and homosexuality.
By human standards, the penguin is the most romantic animal in the zoo, the tour guides say.
The male digs a burrow and decorates it with whatever he can find--even the bones of dead penguins. The female, not easily impressed, drags everything outside. The male brings items back in and the female takes them back out until the two are finally satisfied with the decor.
"They only breed once a year so they have to make the most of it," Tollini says. "It's always boy on top. And they may spend a while before they get it right."
At the other end of the spectrum are the lions, who can mate more than twice an hour, every hour in the day.
"Anybody raise your hand who can beat that record," quips zoo veterinarian Freeland Dunker, another tour guide.
The male bald eagle courts his mate by bringing her offerings of food. Once the female has agreed on a match, the endangered birds mate in flight. As the female soars overhead, the male flies underneath her upside down. The birds lock talons and plummet toward earth.
Orangutans also are anything but passive. "Their sex is quite imaginative," says Dunker. "They can do it swinging from trees. They can do it from all angles and directions."
Flamingos, on the other hand, like an audience--as many as 14 to 20 of the long-legged birds gathered around. "It's a group thing that gets them going," Dunker says.
The little-known tapir, a tropical hog-like animal, has "the most awesome appendage in the zoo," Tollini says. "It bounces on the ground and he steps on it."
Such messages apparently are not lost on the humans on tour. As the trip through the zoo continues, some of the couples become more romantic, holding hands and kissing.
"It can be very educational learning about all the different, imaginative ways it can be done," Shuba Iyengar, 21, a UC Berkeley science major, says after a Saturday tour.
"People could probably learn a lot from the animals and add some variety to their practices," agrees her friend, Rex Winterbottom, 20, a UC Berkeley computer sciences major.
Some of the behavior described by the keepers occurs only in the wild. In fact, much of the animals' sexual activity at the zoo is controlled by humans, who want to breed some species but curb the population of others.
After the populous penguins lay their eggs, for example, keepers replace them with fakes. With other zoo animals, hormone-dispensing devices similar to the kind used in humans to prevent conception, are implanted. Some practice abstinence--involuntarily.
"All of us like to see babies, but we have to be responsible," Dunker says.
If an animal belongs to a rare or endangered species, keepers attempt to breed it with a mate selected to diversify the gene pool. Often, that means using artificial insemination to mate animals from different zoos.
So, how \o7 do\f7 you get sperm from a chimpanzee? With a little encouragement from the zoo workers, it turns out. One keeper in particular is very successful in coaxing samples from the zoo's male chimp. "He has a girl keeper he likes a lot," Dunker says. "When she comes in, boom."
An animal's sexual practices often are influenced by its position in the food chain. Animals with few natural enemies can take their time, performing more elaborate courtship rituals.
Rhinoceroses, for example, engage in foreplay that can last for a month, with mutual affectionate displays that often turn rough. When they finally mate, they can stay together an hour. As the male hops along behind, "she'll walk around, she'll eat grass, she'll have a cigarette," Tollini jokes.
Prey species, however, must mate in a hurry, sometimes almost on the run. Their offspring, too, must be ready to move almost as soon as they are born. "They've got to get in and get out and get a baby on the ground," Dunker explains.