for National Geographic News
A rare panda cub met a not-so-rare panda fate yesterday.
The animal's motherwhich hadn't slept in two daysfell asleep and crushed the tiny two-day-old cub as it nursed, China's state media reported.
Ya Ya, a resident of China's Chongqing Zoo, had given birth to twins on Tuesday.
One sibling was transferred to the Wolong Giant Panda Research Center, because panda mothers are typically unable to raise twins. The second cub remained with her mother.
(Related: China map, facts, video, and music.)
Newborn giant panda cubs weigh just 1/900 of their mother's weight (3 to 5 ounces, or 85 to 142 grams) and resemble a pale pink stick of butter.
When she rolled onto her cub, 16-year-old Ya Ya fatally damaged the newborn's heart, liver, and other internal organs.
Handlers were alerted to the tragedy when the cub fell motionless from her mother's nipple.
Carmi Penny, curator of mammals at the San Diego Zoo, explained that tragedies like Ya Ya's are not uncommon among pandas or other speciesincluding domestic dogs.
"The size differential between [panda] mother and cub is really extreme. The only smaller baby-to-mother [comparison] would be a marsupial," such as a kangaroo, Penny said.
"There's a level of risk in the early hours and early days after a birth. And with a first-time or inexperienced mother, the risk is much higher."
SOURCES AND RELATED WEB SITES