The namesake of the National Zoo's giant panda habitat has pledged a second $4.5 million gift to the panda program, zoo officials announced Thursday.
The donation from David M. Rubenstein will fund the program through the end of 2020.
The news comes less than a month after twin panda cubs were born to the zoo's female giant panda, Mei Xiang. The smaller of the two cubs died four days after birth, but the surviving cub is healthy and growing quickly.
Zoo vets said earlier this week that the newborn now weighs close to two pounds. He has also been spotted scooting around the den.
In addition to the newborn cub, Mei Xiang gave birth to a female cub in 2013, Bao Bao, who has certainly not relinquished much of the spotlight since gaining a little brother.
In a release from the zoo, Rubenstein said the pandas bring joy to millions.
"The National Zoo's panda program has been a remarkable success -- two healthy pandas in just two years -- and I am pleased to support it for another five years," said Rubenstein. "Pandas bring joy to millions and serve as an important cultural bridge with China, as well as yielding important scientific discoveries that help to protect these amazing giant creatures."
With the donation, the zoo will be able to renew a five-year research agreement with the China Wildlife Conservation Association to study panda habitats, and to conduct research on panda reproduction and management, officials said.
In total, Rubenstein has donated $9 million to support the zoo's panda research and conservation program since 2011.
The zoo's panda habitat was named the David M. Rubenstein Family Giant Panda Habitat in recognition of his previous $4.5 million donation.
"David's transformative gift is making a difference at our Zoo in our nation's capital and across the world in China," said Smithsonian Secretary David J. Skorton in the release. "He understands how crucially important it is to our planet, and everyone on it, to improve the sustainability of species diversity."
In 2013, Rubenstein also donated $2 million to support Asian elephant research.