Sad news from the Museum of Life and Science, which was celebrating the birth of three critically endangered red wolf pups last weekend. One of the pups was found dead on Saturday.

“We’re stunned and saddened,” said Sherry Samuels, Animal Department Director, in a press release from the Durham museum.

All three pups had been gaining weight and appeared to be doing well during regular checkups with the museum's animal department and veterinary partners, according to the release. The mother and father also appear to be in good health.

Losses, however, are not unusual in red wolf litters. Two pups from a litter of six born at the museum last April died not long after their birth. A necropsy to help determine the cause of the most recent death has been ordered.

"This is a tough loss for red wolf supporters everywhere and the species as a whole," Samuels said in the release. "While we mourn this loss and wait for answers from the necropsy, we continue to focus on the two remaining pups and their good health."

The red wolf exhibit had been open in the last week. Visitors were able to see the pups in their den via a camera. But, for now, the red wolf exhibit will remain closed, according to the press release.

Less than 300 red wolves, once a top predator in the southeastern United States, live in the wild and in captivity.

According to a recent report from the U.S. Fish and Wildlife Service, the only wild population of endangered red wolves is unsustainable and could be wiped out within a decade after dwindling to a few dozen. The review of the species' status estimates that only about 40 wolves remain in the wild in eastern North Carolina, down from a peak of about 120 a decade ago.

"The population cannot recover from their losses and overcome mortality resulting in a steadily declining population," the review states, predicting these wild wolves could vanish in as little as a decade.

Another 230 wolves live in zoos and wildlife facilities, including the Museum of Life and Science, in what's considered a more stable captive population.