The cubs are the first giant-panda twins born in the U.S. since 1987. They have no names as yet, and their gender hasn't been determined.


ATLANTA - Two giant-panda cubs are being rotated between their mother and an incubator to ensure the newborn twins are fed properly and receive equal doses of maternal nurturing, officials at an Atlanta zoo said Tuesday.

A 15-year-old giant panda named Lun Lun gave birth to the cubs Monday evening at Zoo Atlanta. An ultrasound confirmed Lun Lun's pregnancy in June, but officials say they were unaware she was having twins until the second cub emerged minutes after the first.

"Lun did not really comply with the ultrasound all that well. This pregnancy she slept most of the time," said Zoo Atlanta's deputy director, Dwight Lawson.

He said the mother's long bouts of sleep during pregnancy didn't leave veterinarians much time to check her thoroughly via ultrasound.

Lun Lun was artificially inseminated in March and has been under 24-hour observation by a camera providing a live Internet video feed from her den. The father is another giant panda at the zoo, Yang Yang.

The cubs are the first giant-panda twins born in the U.S. since 1987. Each came into the world hairless and taking on a pinkish color. Lawson said one weighed about 3.5 ounces at birth and the other just over 5 ounces. Lawson said both cubs appear healthy, but zookeepers are taking precautions because of a high infant-mortality rate among pandas.

The cubs are tiny, undeveloped and able to nearly fit in the palm of a hand. They were born with their eyes closed like many mammals, and they're unable to regulate their own body temperature. Zookeepers say rotating the cubs between incubator and the mother is key to their survival.

"They're doing well. The trick with panda twins is that the female typically only cares for one and abandons the other. … They're just not able to raise twins on their own," Lawson said.

Rebecca Snyder, curator of mammals, said Lun Lun is a "good mom" but is reluctant to give up whichever cub she has at any time.

"We have not been able to swap the cubs as frequently as we would like. Because of that, both have been supplemented with some formula. Both are doing well with this," she added.

The cubs won't be named until they are 100 days old, in keeping with a Chinese tradition, Lawson said. Zoo Atlanta officials said they'll likely learn the gender of the cubs in the coming week.