It's official: The National Zoo's new giant panda cub is a boy! Scientists at the Smithsonian Conservation Biology Institute's (SCBI) Center for Conservation and Evolutionary Genetics announced this morning at a press conference that the giant panda cub born last Saturday is male. His twin, also a male, died on Wednesday. Using a method developed by scientists at the SCBI, Zoo scientists determined the gender of the cub by sequencing a short fragment of the zinc finger protein gene.
A paternity test revealed that Tian Tian, the National Zoo's adult male giant panda, is the father of each cub. Mother Mei Xiang was artifically inseminated in April with sperm from Tian Tian and from Hui Hui, a giant panda in China. To determine paternity veterinarians used swabs on August 24 to collect cheek-cell samples from the cubs, which were then compared to those of the adult pandas.
Last night Mei Xiang finally attempted to put the cub down several times to exit the den. The cub squealed each time and she returned to him immediately. At 1:41 A.M. ET, she finally left him long enough to defecate and eat, giving the Zoo staff time to enter the den and weigh the cub. Now at 4.9 ounces grams, they are pleased with his weight gain—an almost one ounce gain in the last 72 hours.
The Rubenstein Family Giant Panda Habitat will remain closed to the public to provide quiet to Mei Xiang and the cub, but both are visible on the Zoo's panda cam. The cub's father Tian Tian and older sister Bao Bao are on view for visitors.