National Zoo's Giant Panda Mei Xiang In Heat, May Breed Soon

WASHINGTON, DC — The National Zoo's beloved giant panda, Mei Xiang, is showing behavioral and physical signs of being in heat, and zookeepers are preparing for the brief window she has to become pregnant.

Mei Xiang is showing signs of estrus, such as: increasingly restless behavior; calling to male giant panda Tian Tian and a rise in estrogen levels, according to the Smithsonian's National Zoo and Conservation Biology Institute.

“The pandas haven’t successfully bred in the past, but we still give them the opportunity,” says assistant curator of giant pandas Laurie Thompson in a news release.

Giant female pandas are able to conceive for barely 36 hours each spring, and zookeepers hope to give Mei Xiang and Tian Tian an opportunity to breed naturally. Scientists also plan to artificially inseminate Mei Xiang with Tian Tian's semen, according to Thompson.

After Mei Xiang and Tian Tian are given the chance to breed, the two pandas will be separated for their protection. Since pandas are such solitary animals, it's likely that the two would become aggressive toward each other after their hormone levels start to decrease.

It'll then take several months to determine if Mei Xiang becomes pregnant. Giant panda fetuses are small and only develop toward the end of gestation, so they aren't detected in an ultrasound until a week or so before they're born, zookeepers said.

Mei Xiang has produced three surviving cubs — Tai Shan, born in July 2005; Bao Bao, born in August 2013 and Bei Bei, born in August 2015. Zookeepers said Mei Xiang went into heat a little later than usual this year, so if she were to become pregnant her offspring would most likely be born around the end of September.

The Giant Panda House is currently closed and will remain closed through Wednesday, zookeepers said.

Photo: Smithsonian's National Zoo & Conservation Biology Institute