ASHEBORO, N.C.--The North Carolina Zoo says two critically endangered American red wolf pups have been euthanized.

The pups, Hurricane and Typhoon (Ty), were part of a pack of five born Sunday, April 15, at the Zoo under the American Red Wolf Recovery Program. Tuesday, May 29, zookeepers discovered two pups had received traumatic injuries as a result of parental aggression from their father.

The Zoo and its veterinarian staff made the difficult decision to humanely euthanize them based on quality of life factors. The cause of the parental aggression is unknown, the zoo says.

“Red wolves are wild animals–their behaviors cannot always be predicted,” said Chris Lasher, Animal Management Supervisor at the Zoo and Species Survival Plan Coordinator for the American Red Wolf. “Even though this pair have had pups in the past and we had observed good parenting skills from both mom and dad with this litter, the father wolf caused traumatic injuries to two of the pups.”

Lasher said staff took as many precautions as possible.

“One of the reasons that these pups are being raised in a quiet, off-viewing area is to try and prevent this type of incident,” Lasher said. “But even with these precautions, we are not always successful in preventing these types of losses that are known to occur in both the wild settings and for wolves under human care.”

North Carolina Zoo Director Pat Simmons describes the deaths as a tough loss for the Zoo and for red wolf advocates everywhere. The entire staff is heartbroken by the loss.

"The North Carolina Zoo is deeply committed to red wolf conservation,” said Roger Sweeney, general curator for the Zoo. “While a setback like this is difficult for our team to experience, the three remaining pups represent an important step forward for the species. We remain focused on fighting to preserve a place for this iconic American species.”

The zook says the remaining pups, Thor, Thunder and Oklahoma (Oakley), are healthy and active and continuing to be monitored daily. They are the offspring of Ayita (female), who is also healthy and active, and Finnick (male), both six years old. Finnick was relocated to give the remaining puppies the best chance of survival.

The loss brings the Zoo’s pack to 21.

The Zoo has been part of American Red Wolf Recovery Program since 1994.