Captive Breeding

In the end, Hannibal did not administer the fatal bite to his mate's neck. And Jao Chu did not immediately kill their offspring, as is often the case. And so, early Tuesday, despite murderous tendencies in the captive species, two newborn clouded leopard cubs were found alive, well and squealing at the National Zoo's Conservation and Research Center in Front Royal, Va.

Hidden by the darkness of a half-moon sky, nine students and their biologist mentor waded through waist-high brush one night last week, hunting for yellow-flowering deer weed to shelter one of the rarest butterflies in America. One student hugged a big, red cylindrical cooler. "I come bearing endangered species," she said. It was no joke. Inside the cooler fluttered dozens of Palos Verdes blues, thumbnail-sized butterflies, all bred in captivity, most just a few days old.

In the darkness of a new moon, a dozen black-crowned night herons landed on a San Pedro beach and stood like sentinels facing the open ocean. "That's a good sign," whispered marine biology researcher Jenn Corpuz, 26. "The herons know there is something coming." Suddenly, the surf shimmered with flashes of silver, and a few small, slender fish wriggled on shore, as if to size up the situation. Then thousands of fish began riding in on the swells and piling up on the beach in writhing clots.

It's rare for a zoo to get an animal from its native land; most animals on exhibit these days were born in zoos. This weekend, the Los Angeles Zoo takes the even more unusual step of sending an animal to its indigenous land. The zoo's male Sumatran rhino, one of the world's most endangered mammals, will return to his roots. Well, technically, his roots are in Cincinnati: He was born at the zoo there in September 2001.

The heat lamps have been blazing for half an hour in Jana Johnson's laboratory, orange light flooding over a sea of plastic cups. Johnson hovers, waiting for metamorphosis. She points at a brown pod in one of the cups. "Look at the seams. This one is ready to pop," she says. The seam widens. A sliver of gray wing appears. "Go. Go. Go," she cajoles. "You can do it. Go."

Stop the presses! Alert the bloggers! The two adult giant pandas at the San Diego Zoo mated Tuesday, zoo officials announced, raising hopes of an offspring this summer. So far, Bai Yun and Gao Gao are two for two during their stay at the zoo under a loan from the Chinese government. The pair mated in 2003 and the male Mei Sheng was born that August. They mated again in 2005 and female Su Lin was born that August.

PROMOTING the sex life of a stud Sumatran rhino from Los Angeles is an intricate affair involving mud, massages and frequent foot rubs. His species may be heading for extinction, but a male still has needs. So Andalas, who flew here from the Los Angeles Zoo in February, is getting the pampered treatment from his Indonesian keepers.

The first panda released into the wild after being bred in captivity has died in China, apparently from a fall. Officials said the body bore injuries inflicted by wild pandas, and the animal may have died trying to escape. The body of 5-year-old Xiang Xiang was found Feb. 19 in the forests of Sichuan province, the official New China News Agency said. He survived less than a year of freedom, despite nearly three years of training on surviving in the wild.

Bai Yun, the giant panda at the San Diego Zoo, is pregnant, zoo officials said Tuesday. The father is Gao Gao, also at the San Diego Zoo. Bai Yun, 16, has had three cubs at the zoo: Hua Mei in 1999, Mei Sheng in 2003 and Su Lin in 2005. Bai Yun has been taken off exhibit and is expected to give birth within weeks, officials said.

Papa salmon plus mama salmon equals. . . baby trout? Japanese scientists put a new spin on surrogate parenting as they engineered one fish species to produce another, in a quest to preserve endangered fish. Next month, Idaho scientists will try to produce sockeye salmon, highly endangered in that state, using more plentiful trout as surrogate parents.