The curator said he and his colleagues will talk with their Chinese partners about how best to continue the conservation programs.

Karen Wille, who works for Pandas International, a US nonprofit organization, said Xiao Qi Ji is very special to many visitors because they just watched him grow in front of them.

"I'm sad that they're leaving, but I know that they'll have a wonderful life in China," she said. "I know they will. Because I've been to China. So I've seen the way the pandas are treated and taken care of. And they're so good to them. But we won't be happy because they'll be gone."

Local visitor Benjy Renton said, "I really hope that we can continue to receive pandas in the near future, and continue those partnerships, not just here in DC but also with other zoos around the country."

Before the pandas leave, there will be a "Panda Palooza," a giant celebration of the five decades of the pandas' presence at the zoo.