A giant panda at a zoo in China's Chongqing municipality is inconsolable after she nodded off and crushed one of her two-day-old twin cubs to death.

A zoo official told Chongqing Morning Post: "She had been devoting all of her attention to the baby for about 56 hours since its birth without any rest."

An autopsy revealed the 90g cub died of a ruptured heart and liver. Adult panda females average around 80kg, about the same as a large man.

One of the many reasons for the troubles besetting giant panda conservation efforts is the vulnerability of their cubs. With mothers' nutrient-poor bamboo diet, newborns are very weak and small, and require near-constant nursing.

The zoo said: "Yaya appeared to be so sad when she couldn't find her baby after she woke up just 10 minutes later. She looked as though she had known what was going on. Tears could be seen in her eyes."

Giant panda chief Guo Wei said: "Pandas who lose their young tend to be depressed for a month or so." He added that the zoo would give Yaya extra care and provide special food to improve her mood. ®

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