The pair are the first twin panda cubs born anywhere in the world this year.
Li Li gave birth to the twins on Thursday after a 113-day pregnancy. The nine-year-old mother, mated with a 16-year-old male panda, named Ha Lan, earlier this year.
"We were very careful with Li Li as this was her first birth," said base director Li Guanghan.
Due to the high summer temperatures being experienced in Chengdu, the base moved Li Li and all its other pregnant pandas into a new, air-conditioned delivery room early last week.
Soon after being transferred, Li Li became restless and began eating less - signs of an imminent birth. Li Guanghan and other researchers then kept a round-the-clock watch on her.
When Li Li's water broke at 9 am on Thursday, it became apparent she was having a breech birth.
As with humans, most panda cubs are born head first, so the base's veterinarian team treated this as a rare and dangerous case.
At 10:20 am, just as the medical group was about to assist the delivery, Li Li stunned the group members by grasping the cub with her mouth and delivering it unaided. Such a delivery had never happened in the base before.
Immediately after the cub was born, Li Li embraced and licked the 160-gram newborn.
At 11:35 am, the second cub was born normally.
To protect the endangered species, the Sichuan provincial government has built Wolong, Tangjiahe and Fengtongzhai giant panda nature reserves.
Any one with suggested names for the twin cubs could call the base at 028-3510022 or 028-3510033.
(Xinhua News Agency 07/17/2001)
