The first cub born to female lion Nababiep (pictured) earlier this week has died. Photo by Mehgan Murphy, courtesy Smithsonian’s National Zoo.

Awful news for baby animal lovers. Officials at the Smithsonian’s National Zoo confirm that the lion cub born Tuesday has died.

Lion keepers observed Thursday evening that the cub had stopped responding to its mother, and after moving mom Nababiep out of her den, were able to confirm the death. The cub had been a boy, zoo officials said.

According to a news release, the zoo’s pathologists determined that the cub died from pneumonia brought on by having inhaled a small, sharp piece of straw. Straw is commonly used as bedding for animals at zoos, including the National Zoo.

“Losing this lion cub is devastating for all of us at the National Zoo,” said National Zoo director Dennis Kelly in a statement. “I believe this was a one-in-a-million fluke. Unfortunately, this is the downside to the ‘cycle of life.’ But, the animal care team and Zoo staff are consummate professionals, and I know they’ve learned a tremendous amount from creating the pride, breeding the lions and getting Nababiep through her first birth. We mourn this loss yet keep our focus on the best care for the lion pride.”

Zoo officials say Nababiep has rejoined her sister Shera, and that both females will be reunited with male lion Luke in the near future.