The National Zoo's panda parents, Mei Xiang and Tian Tian, have a son. The zoo announced this morning that the surviving panda cub is male and the son of the zoo's male panda, Tian Tian. Mei Xiang gave birth to fraternal twins Saturday, but the smaller cub—also a male fathered by Tian Tian—died Wednesday. Officials say the most likely cause of death was pneumonia, the result of complications from breathing in food particles. It's difficult for panda moms to care for twins without outside help, NBC Washington notes; keepers had been trying to swap the newborns back and forth to make sure each received proper care, but to no avail.
Meanwhile, the surviving cub is said to be doing well. "Mother Mei Xiang is showing proper maternal care, which includes short sleep cycles and adjusting the tiny cub in her arms for better positioning and grooming," the zoo said in a statement yesterday, per NBC, which also noted the cub was "continuing to make strong vocalizations." Tian Tian is the father of Mei Xiang's other cubs, daughter Bao Bao and son Tai Shan. During this year's panda breeding, Mei Xiang was artificially inseminated with semen from Tian Tian and a panda in China that was deemed a good genetic match. (Breeding pandas is incredibly tricky.)