UPDATE 1-Giant panda cub died of liver necrosis, Washington zoo says


(Adds details about panda cub)

WASHINGTON, Oct 11 (Reuters) - The giant panda cub that diedat the National Zoo in Washington last month succumbed to liverdisease caused by inadequately formed lungs, officials said onThursday, releasing findings they hope will help them learn moreabout breeding the endangered black and white bears.

The cub, born on Sept. 16, died when it was six days old inan agonizing blow to wildlife conservation efforts.

Veterinarian Suzan Murray of the National Zoo said officialswere unsure why the cub's lungs failed to form properly, butsaid the scientific community hopes to learn more about thecauses of death in giant panda cubs.

Murray said the cub's mother, Mei Xiang, who gave birthafter years of failed efforts at conception, at age 14 could benearing the end of her cub-bearing years. But Murray did notwrite off the possibility Mei Xiang could again give birth.

"We're hopeful that she would be able to again in thefuture," she said at a news conference.

The cub was never given a name, in line with a Chinesetradition that pandas are not named for 100 days. The arrivalwas cause for celebration among zoo officials and wildlifeconservationists around the world given the daunting odds forthe endangered species reproducing in captivity.

Fewer than 1,600 giant pandas are known to exist in the wildin China, and about 300 live in zoos and wildlife centers aroundthe world. Breeding is a critical challenge. One in five cubsborn in captivity die in their first year of life, the NationalZoo said on its website.

The cub's death on Sept. 23 was discovered after pandakeepers and zoo volunteers heard a distress sound from MeiXiang. The zoo's staff failed to revive the cub with lifesavingmeasures, including CPR.

Since then, zoo officials have been closely monitoring MeiXiang, who spent a couple of weeks cradling a rubber toy as ifit were a cub.

Don Moore, an animal behaviorist at the National Zoo, saidthe mother had recently set aside the toy and her behavior wasslowly returning to normal. He said she was still down about 20pounds (9 kilograms) from her usual 240 pound (109 kg) weight.

He said the zoo had received a flood of support for MeiXiang.

"We did get a lot of cards and letters and even stuffedanimals," he said.

(Writing by Paul Thomasch and Dan Burns; Editing by VickiAllen)