WASHINGTON -- National Zoo scientists have determined a 6-day-old giant panda cub's death last month wasn't momma bear's fault, and life was returning to normal Thursday for giant panda Mei Xiang.
The panda mom has stopped cradling a toy and left her den to spend more time in her yard. On Thursday morning, she strolled outside, found a frozen, fruity popsicle and turned her back to a gathering crowd to enjoy breakfast.
Mei Xiang's cub, born Sept. 16, died of liver trouble and signs of lung disease, said Chief Veterinarian Suzan Murray. After a full necropsy, scientists found the tiny female cub's lungs hadn't fully developed and likely weren't sending enough oxygen to the liver.
The cub was possibly born prematurely.
Zoo scientists are trying to learn more about how common liver and lung defects are in newborn pandas.
"As unfortunate as this was, this baby and studies of this baby post mortem are contributing to our knowledge of panda reproductive science," said Donald Moore, the zoo's associate director for animal sciences.
Zoo keepers have said Mei Xiang took careful care of the cub. It weighed only about 4 ounces when it died. The tiny hairless, helpless creatures can be easily crushed, but the cub had no sign of injury. A small amount of milk in the digestive system suggested she had nursed.
Panda fans keeping tabs online were devastated by the death.
Mei Xiang's appetite is slowly returning to normal. She stopped eating and stayed in her den for nearly a month to give birth and care for the cub. Now she's eating about 80 percent of her bamboo, fruits, vegetables and biscuits. She's still about 20 pounds under her normal weight of 240.