Birds do it, bees do it, even educated fleas do it. So go the lyrics penned by U.S. songwriter Cole Porter. Porter, who first hit it big in the 1920s, wouldn't risk parading his homosexuality in public. In his day "the birds and the bees" generally meant only one thing—sex between a male and female. But, actually, some same-sex birds do do it. So do beetles, sheep, fruit bats, dolphins, and orangutans. Zoologists are discovering that homosexual and bisexual activity is not unknown within the animal kingdom. Roy and Silo, two male chinstrap penguins at New York's Central Park Zoo...