Prized San Diego Zoo panda mom Bai Yun gave birth Wednesday to her fifth cub after a 130-day pregnancy that zookeepers said ended with an apparently pleasant labor.
The cub born to 17-year-old Bai Yun (White Cloud) became just the 14th panda in the United States.
Shortly before the birth, the mother licked herself, rolled on her back to grab her hind legs and stood on her head.
"We saw a contraction and then about five seconds later, we just heard a wailing cry of the cub. ... it was a very vocal cub, it was like whoa ... it's got a really good set of lungs," veterinarian Dr. Meg Sutherland-Smith said at a news conference.
"She really had, I think, a very pleasant labor, not that I would know, but she didn't have seemingly as much discomfort or moving about as what we've seen in the past," she said.
Bai Yun seemed comfortable with the cub and appeared to start nursing about 30 minutes after birth.
"She knows she's been there, done that," Sutherland-Smith said.
A second fetus had been detected, but Mehlow said it was probably absorbed in the mother's uterus.
The pink, nearly hairless panda newborn weighed about four ounces and is about the size of a stick of butter. Its gender won't be known for about a month, Mehlow said, and it won't get a name for 100 days, in line with Chinese tradition.
Mom and cub will lead private lives for the next four months or so, but they will appear on the zoo's live Panda Cam, which can be watched online.
Bai Yun, who weighs about 300 pounds, was born in a breeding center in China and arrived in San Diego in 1996.
The zoo announced just last week that Bai Yun was pregnant, based on ultrasound tests.
The father is longtime consort Gao Gao (Big Big), who has fathered three of Bai Yun's other cubs.
The number of cubs makes the pair one of the most reproductively successful panda couples ever in captivity.
Pandas are notoriously poor breeders — one reason their species is endangered — and females have only three days a year in which they can conceive. Only about 1,600 giant pandas remain in the wild, and around 200 live in captivity, the zoo's conservation program specialist, said Megan Owen, the zoo's conservation program specialist.
Bai Yun and Gao Gao come together only a couple days a year. When Bai Yun enters her fertile periods, zookeepers make sure Gao Gao is there, sniffing her through a perforated gate zookeepers call a "howdy door" until her chirps and bleats indicate she's ready to get down to business.
Zookeepers initially had little hope for the pair because Bai Yun is big for a female and Gao Gao is small for a male, said Owen.
"Watching them mate is kind of excruciating because it takes a long time for them to get the position right, but they always do," Owen said. "She is great at letting him know where she's at in terms of her cycle, and he is also very good at advertising his interest. ... Their model of communication is something that all couples could benefit from."
Gao Gao will not have any role in raising the cub.
Bai Yun gave birth to her first cub in 1999 through artificial insemination from her first arranged suitor, Shi Shi (Stone).
Hua Mei (China/U.S.A.) was the first giant panda cub born in the United States after a decade of failed breeding attempts. She has had three sets of twins since returning to China in 2003.
The Chinese government has a right to bring the new panda cub to China when it turns 4, said Carmi Penny, curator of mammals at the zoo.
Gao Gao, who was born in the wild, arrived in San Diego in 2003 after veterinarians gave up on Shi Shi, who turned out to be older and less virile than originally believed and was returned to China. Shi Shi died last year.
Some males never succeed at natural breeding, so artificial insemination has become common practice when breeding captive pandas.