The panda cub born September 16th at the National Zoo in Washington, D.C. has sadly passed away this past Sunday. Zookeepers were alerted to something being amiss upon hearing the cub's mother Mei Xiang issuing a "distressed honking noise" early Sunday morning. After an hour spent retrieving the cub, veterinarians attempted to revive it only to have it die six minutes later.

Zoo officials are heartbroken over the loss of the cub, which, in accordance to Chinese tradition, had yet to be named. The cub was the result of a long string of attempts to impregnate Mei Xiang through artificial insemination and was the only cub to make it full term. Says zoo director Dennis Kelly to the New York Times, "These bears are so critically endangered that every cub is important. This is devastating for all of us here."

Up until this weekend, zoo officials say that the cub — whose sex was unknown — seemed in good health with "no outward sign of trauma or infection." The small panda was even seen moving and grunting in surveillance footage released by the zoo on Friday.

Joy Turns to Despair at National Zoo as Newborn Panda Is Found Dead [NYT]