Imperial Valley News

San Diego, California - The 24-hour birth watch at the San Diego Zoo came to an end today when giant panda Bai Yun gave birth to her fifth cub. The birth was witnessed at 4:58 a.m. by the giant panda team watching the Zoo's closed-circuit camera placed in the birthing den.

The sex of the mostly hairless, pink newborn, which is about the size of a stick of butter, will not be known for some time, and it will be approximately one month before the iconic black-and-white coloration of a giant panda becomes visible.

"The birth of our fifth cub is just as exciting as our first," said Meg Sutherland-Smith, San Diego Zoo veterinarian. "With every pregnancy and birth we're learning more about the reproductive process of the giant panda. Now that she's given birth, we're just watching Bai Yun to make sure that she continues to care for this cub as well as she's cared for all the others."

Bai Yun will care for the cub, which is estimated to weigh about four ounces, unless there are complications and the giant panda team will need to intervene. In the past, Bai Yun has been a careful, attentive mother and there has been no need for human involvement. The Zoo's panda team does not expect to examine the cub until the mother begins to regularly leave the den. This usually happens after three weeks.

Bai Yun gave birth in an off-exhibit den used during her previous pregnancies. Bai Yun and the cub will remain in the den for four to five months. The father, Gao Gao, has no role in raising the cub.

During the denning period, the only way to see the panda cub and mother will be through the San Diego Zoo's live Panda Cam, available at www.sandiegozoo.org/pandacam

A second fetus was detected during an ultrasound in July, but the giant panda team believes it was resorbed in the uterus, leaving only one cub to be born. A similar situation happened during Bai Yun's pregnancy in 2005.

A panda's fertilized egg remains suspended in the uterus until a prompt in the environment causes it to implant. Scientists do not know what prompts the implantation. Implantation of the fetus can be delayed as much as two to three months after fertilization. After implantation, the fertilized egg begins to develop. Impending birth is predicted on the basis of behavioral, hormonal and anatomical changes that are documented by scientists at the San Diego Zoo's Institute for Conservation Research.

In 1999, Bai Yun's first cub, Hua Mei, became the first giant panda conceived by artificial insemination in the Western Hemisphere and the first in the United States to survive to adulthood. Hua Mei is now in a breeding program in the People's Republic of China along with her brother, Mei Sheng, Bai Yun's second cub that was born at the Zoo in 2003. Mei Sheng, as well as Bai Yun's daughters, Su Lin and Zhen Zhen, were conceived through natural breeding. Their father is Gao Gao.

Bai Yun was born at the China Center for Research and Conservation of the Giant Panda in the Wolong Nature Reserve on Sept. 7, 1991. She was the first panda to be born and survive at the breeding center. Bai Yun, whose name means "white cloud" in Chinese, arrived at the San Diego Zoo in September 1996 on a research loan.

Gao Gao is a wild-born giant panda that arrived at the San Diego Zoo in 2003 from the Wolong Nature Reserve. He is the sire of four of the five cubs born to Bai Yun. Gao Gao was found in the wild dehydrated and suffering from a nutritional deficiency when he was about 6 months old. He also suffered a wound to his left ear, possibly from another animal.

The 100-acre San Diego Zoo is dedicated to the conservation of endangered species and their habitats. The organization focuses on conservation and research work around the globe, educates millions of individuals a year about wildlife and maintains accredited horticultural, animal, library and photo collections. The Zoo also manages the 1,800-acre San Diego Zoo's Wild Animal Park, which includes a 900-acre native species reserve, and the San Diego Zoo's Institute for Conservation Research. The important conservation and science work of these entities is supported in part by The Foundation of the Zoological Society of San Diego.