Lung, liver damage caused baby panda's death

WASHINGTON (CBS) -- We now know what caused the death of a 6-day-old panda cub at Washington's National Zoo. Officials blame her death on liver and lung problems.

Giant panda Mei Xiang sits in her yard at Washington's National Zoo without her baby cub. Zoo scientists revealed what killed the 6-day-old cub last month. Chief veterinarian Dr. Suzan Murray says, "The immediate cause of death was liver, liver necrosis or nepatic necrosis which means death of liver cells. There was also evidence of lung disease; the lungs were not fully formed."

The female cub was born September 16th and appeared healthy. A week later, distress calls from her mother alerted zoo officials that something was wrong.

The death devastated the staff at the zoo as well as panda fans. So much time and energy is spent trying to breed this endangered species.

Mei Xiang, 14, had five failed pregnancies before becoming pregnant this time through artificial insemination.

Zoo officials say Mei Xiang's behavior is slowly returning to normal after the cub's death. National Zoo Associate Director of Animal Care Services Dr. Don Moore says, "She started eating 80% of her bamboo and the same in her biscuits and her fruits and vegetables. She has been choosing for awhile now to go out of the den."

But her future and the future of her partner Tein Tein are uncertain. Zoo officials will have discussions later this fall with their colleagues in china whether to keep the pandas in the breeding program.

As few as 1,600 giant pandas survive in the wild in China. More than 300 pandas live in zoos and breeding centers around the world.