Liver Problem Killed Baby Panda: Zoo Mother Mei Xiang reportedly improving By Newser Editors and Wire Services Posted Oct 11, 2012 10:03 AM CDT 5 comments Comments In this Dec. 19, 2011 file photo, Mei Xiang, the female giant panda at the Smithsonian's National Zoo in Washington, eats breakfast. (AP Photo/Susan Walsh) (Newser) – A National Zoo veterinarian says a liver problem was indeed to blame for the death last month of a 6-day-old giant panda cub. Chief veterinarian Suzan Murray told a news conference today that the cub's cause of death was liver necrosis, or the death of liver cells. Murray says the cub's lungs were also underdeveloped and likely didn't provide enough oxygen to the liver. The zoo also offered a glimpse of panda mother Mei Xiang in her yard today. Her behavior has slowly returned to normal since the cub's death. The cub, believed to be female, was born Sept. 16. Zoo officials and panda fans were devastated by its death less than a week later. The birth was a surprise because it hadn't been clear whether Mei Xiang was still fertile.