When a male lion cub was born at the National Zoo May 18, the veterinarians thought they’d accomplished the unthinkable; many thought that breeding African lions Nababiep and Luke would prove to be impossible. The new cub was the next step in the development of an entire lion community. But their the hopes were shattered when the cub died May 20, a fluke in the “circle of life.”

The cub died of pneumonia, caused by inhaling a grass straw, according to chief veterinarian Suzan Murray. This case of pneumonia is rare.

The lion keepers were slowly integrating the adult male lion with two sisters in the hopes that they would breed and form a community of lions. The death is a setback in their progress, and could affect the zoo’s popularity among students, who say that they would be more likely to go to the zoo if the cub had survived.

“[Lions are] cute, and there are rarely lion cubs at the zoo so it would be something to see,” freshman Elizabeth Wright says. “I’ve never seen a lion cub before—I might want to just take it home.”

Lion veterinarian Christa Clark agrees that these “cute” animals are a popular attraction.

“Lions are very charismatic, and they’re social,” she says in an interview on the National Zoo website. “So they’re good exhibit animals.”

Despite the loss, the cub’s mother, Nababiep, seems to be emotionally and physically healthy.

“We can’t say for certain what the psychological impact was,” Murray says. “[But] we can say that our keepers took great care to provide her with companionship as soon as possible and she currently appears quite well.”

Murray says that there is still hope for another cub.

“Although we’re very saddened by the loss of our first cub, our other female lion bred recently,” she says. “We will be monitoring her for signs of pregnancy and we’re hopeful that we’ll have more cubs.”