Zookeepers are hand-feeding the second, smaller cub. (Photo by Shellie Pick, Smithsonian’s National Zoo)

Some sad news from the National Zoo: one of Mei Xiang’s newborn panda cubs has died.

We are sad to report that the smaller of the two panda cubs has died. We will continue to provide updates on social media w/ #Pandastory.

— National Zoo (@NationalZoo) August 26, 2015

Recently, Mei Xiang had been playing favorites with her new babies and, as a result, the smaller of the two cubs wasn’t getting enough attention, Zoo officials said yesterday. The panda team had been intensely monitoring the new cub, unsuccessfully trying to swap it out with the larger cub in Mei Xiang’s care during this “high-risk period.”

In a press conference today, National Zoo officials said that they had successfully swapped the larger panda cub with the smaller one yesterday, but when they went to swap the cubs again, they noticed the “smaller panda appeared weaker and was exhibiting respiratory issues.” The cub’s condition continued to decline throughout the afternoon and it died just after 2 p.m. today.

Zoo officials said they would not know what the exact cause of the panda cub’s death was for quite some time. They did, however, say that both Mei Xiang and the other cub are “very healthy,” and they’re doing everything they can to ensure the remaining cub survives.

Naturally, PETA—who yesterday condemned the Zoo’s care of the panda cubs—were quick to issue a statement blaming the Zoo for the cub’s death. “From the moment of the first panda birth, the newborns were handled by humans and turned this way and that under the camera lights,” PETA President Ingrid E. Newkirk said. “It was inevitable that the poor little cub was too unthrifty to survive, but in nature the mother would not have manipulated him, force-fed him, and treated him like an exhibit.”

Because if there’s one organization that’s going to criticize the round-the-clock staff working to ensure the survival of an endangered species, it’s the one that routinely dispatches scantily clad women to shame people into becoming vegetarians.