Zoos rethink matchmaking tactics for endangered species_美文

Zoos rethink matchmaking tactics for endangered species

Thousands have been bred in captivity. Some have already been reintroduced in Tunisia, and there are plans to release more soon, according to the Sahara Conservation Fund.

China's giant panda breeding program has also been "extraordinarily successful," Wildt said.

China maintains a core population of captive pandas and rents some out to mate in zoos around the world, with the caveat that the animals must eventually return home.

"They only have one shot per year," said Pierre Comizzoli, a research scientist who works with the solitary bears at the National Zoo.

The 100-114 kg pandas rarely manage the position needed to conceive naturally, so zoo experts resort to artificial insemination.

Most years, the attempts have failed. One panda cub born in 2005 at the National Zoo has survived to adulthood. This year, experts for the first time used samples from two different bears, including one from a San Diego zoo.

A so-far healthy, baby giant panda was born on Aug 23 though its paternity will remain a mystery until the DNA tests come back. A second cub emerged stillborn a day later.

For other species, like the critically endangered Sumatran rhinoceros, inbreeding is now the only option left, US zookeepers say.

In the wild, as few as 100 remain in Indonesia and Malaysia. The females ovulate only if a potential mate is nearby - which isn't always the case.

A Cincinnati Zoo team began working with Sumatran rhinos in the 1990s and finally succeeded in getting a pair to breed in 2001, producing the world's first calf born in captivity in 112 years.