12/19/2011 09:19 am ET Updated Dec 19, 2011

National Zoo Panda Program Gets $4.5 Million Donation (PHOTOS)

WASHINGTON -- There's great news for panda fans: The Washington Post reports that the National Zoo's panda reproduction program will be receiving a $4.5 million donation from philanthropist David M. Rubenstein, who is a co-founder and managing director of the Carlyle Group and a member of the Smithsonian's Board of Regents.

The zoo's two pandas -- female Mei Xiang and male Tian Tian, both teenagers -- are on loan from China until Dec. 6, 2015.

Mei Xiang gave birth to male cub Tai Shan in 2005 -- Tai Shan was returned to China in 2010. The zoo director told the Post that the zoo is hoping Mei Xiang and Tian Tian produce a panda cub in the coming year:

Zoo officials said they have recently detected "power walking" in Tian Tian, an indication that he senses his mate is approaching estrus. When that happens, the two will be allowed to try to mate naturally, something they have not been able to do successfully. (Tai Shan was conceived through artificial insemination.)

If they are unsuccessful, Mei Xiang will be artificially inseminated again. If that doesn't work, the zoo can explore the possibility of replacement giant pandas with the Chinese, officials have said.

The Smithsonian will be announcing the donation at a news conference at 9:30 a.m. on Monday, at the zoo's Giant Panda Habitat.

Giant Pandas

RELATED VIDEO: A 2009 video about the Smithsonian's panda breeding program.