Twin giant panda cubs born at Madrid Zoo
The cubs, whose genders are not yet known, were conceived through artificial insemination after mother Hua Zui Ba and father Bing Xing failed to procreate on their own. They are the first giant panda twins to be conceived using the method outside of China, according to Xinhua, China's official news agency.
Hua Zui Ba and Bing Xing arrived in Madrid for a 10-year stay through an agreement with China in 2007. Panda experts with the Chengdu Panda Base in China's Sichuan province collaborated with members of the Spanish National Research Council on the effort to produce the pair's offspring through artificial insemination.
The cubs are the first offspring for Hua Zui Ba. The new mother "nursed only the first cub as her own and ignored the second, which was nursed by zoo workers instead," Xinhua reported.
Tradition dictates that giant panda cubs don't receive names until they are 100 days old.
[Correction: An earlier version of this post said that the Madrid Zoo's giant panda cubs were the first conceived through artificial insemination outside of China. In fact, they're only the first set of giant panda twins conceived outside of China using the method. We've corrected the error; thanks to astute reader Melissa for pointing it out!]
-- Lindsay Barnett
Photo: A zoo staff member feeds one of the cubs on Sept. 7. Credit: Associated Press