Pandas have a lot working against them when it comes to to making babies: a once-yearly ovulation cycle, genetic inbreeding due to a limited captive population, and, apparently, some degree of ineptness at copulation itself. Zoo officials frequently see their excitement crushed by what turn out to be pseudopregnancies, and newborn cubs often don't survive, writes the Washington Post.
The four US zoos with pandas have spent lavishly on them, including $35 million in rental fees to China. That rental deal means that the young Tai Shan, whose birth was a coup for the National Zoo, will soon be headed back to China. But the National Zoo doesn't mind the high price: "We lost money on Apollo, too, you know."