Pandas are notoriously poor breeders, and often have false pregnancies.
WASHINGTON -- Mei Xiang, the giant panda at the National Zoo, gave birth early Saturday to a baby the size of a stick of butter.
Time of birth was 3:41 a.m. Gender and weight are unknown as nobody dares go near the mother and cub at this extremely delicate time. Mei Xiang weighs more than 250 pounds. Both are being closely monitored and are doing well, according to Zoo spokeswoman Peper Long.
"Giant panda cubs are very fragile and small. We will intervene only if we need to do so," said Long.
National Zoo pandas have had five births over the years but only one baby lived for any amount of time -- a few days.
"The cub came out squealing," according to Lisa Stevens, associate curator for pandas and primates at the National Zoo. "We knew right away we had a healthy cub from that squeal."
Pandas are notoriously poor breeders. Females come into heat for two or three days a year, false pregnancies are common, and cubs are so small that sometimes their mother accidentally crushes them. This worsens their chances of survival in the wild, where only about 1,600 are left in the shrinking bamboo forests of China.
The round-the-clock pregnancy watch was down to its last few days, but National Zoo keepers still did not know whether their nest-building, apple-cuddling, sleepy female giant panda would, in fact, become a mother.
On Friday, a hormone test of Mei Xiang's urine kept their hopes alive, but pandas also have false pregnancies that mimic real ones. Scientists had hoped to detect a fetus, which weighs a quarter-pound, by means of a sonogram, but Mei Xiang has refused to sit still for an ultrasound since June 20.
The hormone readings, though, told them that the waiting should be over -- one way or the other -- by the middle of next week.
The panda house will be closed to the public for at least three months, but the outdoor yard is open and visitors can sometimes see the male panda Tian Tian there. It may be weeks before the female panda leaves her den and it could be weeks or months before zoo officials will be able to get close enough to determine if the cub is a male or female.
Mei Xiang was artificially inseminated March 11. She will be 7 years old this month -- prime breeding age.
Mei Xiang and her mate arrived in 2000 on a 10-year loan from China.