(Reuters) — Giant panda Mei Xiang, a star tourist draw in the U.S. capital, gave birth to a pair of cubs hours apart on Saturday (August 22), the National Zoo said. Mei Xiang gave birth to her first cub at 5:34 p.m. (2134 GMT) after her water broke about an hour beforehand, zoo officials said. About four and one-half hours later, at 10:07 p.m., a second cub arrived and appeared healthy, the zoo said. […]