What can I say, just heard about this and thanks to Zoo Atlanta for posting an update right away. Here is the Zoo's statement.
Thursday, September 22
We recently received some surprising news from our colleagues at the Chengdu Research Base of Giant Panda Breeding about Mei Lan, the first giant panda cub born at Zoo Atlanta. She is actually a he, and it seems that he was incorrectly sexed when he was a cub. Mei Lan has lived at the Chengdu Research Base since February 2010, and our colleagues there have noted the appearance of testes.
Giant pandas are normally sexed as infants during early health checks. This can be difficult to do correctly, and it helps to have some practice. Mei Lan was sexed during his first veterinary exam when he was 19 days old by a staff person from the Chengdu Research Base and Zoo Atlanta staff. This is later than would normally be done at the Chengdu Research Base, and it’s more difficult to do if the cub is more than a few days old. We waited longer to do Mei Lan’s first exam, because Lun Lun was a first-time mother and we didn’t want to do anything that might disrupt the excellent care she was providing for Mei Lan.
Close examination of the anogenital area is needed to determine the sex of a giant panda cub, and a male’s testes do not descend until he is over 3 years old. Prior to this, there is no obvious external cue to sex. As a result, young giant pandas are occasionally sexed incorrectly, which was apparently the case for Mei Lan. We plan to recheck the sex of our other young giant pandas, Xi Lan and Po, during their next scheduled physical exams.
Although it’s strange for us to think of Mei Lan as a male, the good news is that this does not change how he was cared for and managed while he was growing up here in Atlanta. We all recall that his birth on September 6, 2006, was a monumental event for Zoo Atlanta, the City of Atlanta, the Giant Panda Species Survival Plan, and thousands of you, his fans, from around the world. He was the only giant panda cub born in the U.S. in 2006, and there was nothing we would have done differently if we or the staff from the Chengdu Research Base had known sooner that he was a male. He still would have been transferred to the Chengdu Research Base when he was 3 years old, and he will still be an important part of the breeding population there. So while this news does come as a big surprise, we’ll all just work on getting used to the fact that Lun Lun’s and Yang Yang’s firstborn was a son, and that son may have a bit of an odd name (Mei Lan roughly translates to Atlanta’s Beauty) for a male. I don’t think he’ll mind. I’ll bet Lun Lun knew all along. Too bad we couldn’t just ask her!
Rebecca Snyder, PhD
Curator of Mammals