WASHINGTON -- A giant panda at the Washington Zoo surprised zookeepers by becoming a mom again after years of failed pregnancies.
Zoo scientists had all but given up on 14-year-old Mei Xiang's chances of conceiving, but they were watching for a possible cub nonetheless, as she was artificially inseminated earlier this year. She gave birth late Sunday, her first cub since 2005.
Like all newborn pandas, the cub is pink, hairless and about the size of a stick of butter. Following Chinese custom, it will be given a name after 100 days.
Four American zoos have pandas, but Washington's have special significance. The zoo was given its first set of pandas in 1972 as a gift to commemorate President Richard Nixon's historic visit to China.
Mei Xiang and her mate Tian Tian, born in China, are the second pair of pandas at the zoo. They're treated like royalty, and any offspring gets immediate star status.
"There's something very special here with our pandas," said giant panda curator Brandie Smith. "Everyone is part of our family. We, Washington, D.C., have had a baby panda cub."
Mei Xiang delivered her first and only other cub, a male, Tai Shan, in 2005. Since 2007, there had been five unsuccessful attempts with artificial insemination. Each time, she went through a "pseudopregnancy," building a nest and experiencing high hormone levels. But each time there was no cub.
Scientists worried she had become infertile and believed there the chance she would become pregnant after so many failed attempts was less than 10 percent. They had considered replacing Mei Xiang or 15-year-old Tian Tian with other pandas.
Still, there was hope.
Laurie Thompson, one of the about half a dozen panda keepers at the zoo, said each keeper gave Mei Xiang a pep talk.
"I know you can do this. You need to prove them wrong. You need to have a baby this year," she said she told Mei Xiang, with whom she has worked since 2000.
Thompson got a phone call Sunday from another keeper, who said, "I think I hear a panda cub." Keepers watched the zoo's panda cam on their computers. Sure enough, there was the unmistakable bird-like screech of a cub.