Panda cubs are born at National Zoo

Tyler Pager | USA TODAY

Show Caption Hide Caption Twin panda cubs born at National Zoo The panda cubs were born more than four hours apart at the Smithsonian National Zoo in Washington. Panda fans raced to the zoo to witness the first delivery by mom Mei Xiang on live video.

The giant panda at the National Zoo gave birth to twins Saturday.

The Zoo tweeted that Mei Xiang gave birth to the first cub at 5:35 p.m and to the second cub at 10:07 p.m. The panda's water broke around 4 p.m., officials said. It could be months, however, before the new cubs makes a public appearance.

At a press conference Saturday evening, officials said they do not know the sex or the paternity of the cubs, but both will be determined.

“All of us are thrilled that Mei Xiang has given birth," said zoo director Dennis Kelly. “Thank you to all of our excellent keepers, veterinarians, researchers and Chinese colleagues who contributed and therefore deserve credit for this conservation success.”

Throughout the day Saturday, the panda was displaying behaviors consistent with being in labor, such as body-licking and being restless, said Annalisa Meyer, a spokeswoman for the National Zoo. The public can observe the giant panda on the Zoo's live panda camera.

Mei Xiang was artificially inseminated twice in April — once from the semen on Tian Tian, the giant male panda at the National Zoo, and once from the semen of a panda in China. On Aug. 19, officials at the zoo said they believed they spotted a fetus in Mei Xiang during an ultrasound test.

Mei Xiang and Tian Tian are the parents of Tai Shan, who was born in 2005, and Bao Bao, who was born in 2013. Bao Bao turns 2 on Sunday.