The death of a 3-year-old gray wolf last month was linked to complications during a routine capture and collaring operation that led to acute heart failure, according to a necropsy performed by Colorado Parks and Wildlife.
The operation Jan. 28 led to acute cardiogenic shock, which could have been exacerbated by several different factors, the agency said Friday, including hyperthermia, respiratory distress, drug reaction or capture myopathy, which is a disease that causes severe muscle damage in wild animals after extreme exertion or stress.
The breeding male was part of the King Mountain Pack, a wolf family that formed last spring in Routt County. The wolf was one of the 10 wolves brought to Colorado from Oregon.
The collaring effort was part of Colorado’s wolf reintroduction plan to keep at least two members of each pack collared. Crews also captured a breeding female and a pup to place collars on them.
During the capture, Colorado Parks and Wildlife said the wolf was not panting in any abnormal way and saw no signs of distress, the agency said in a news release. The wolf was darted in its muscle in its upper left hind leg.
Once brought to CPW’s handling crew, wildlife officials took temperatures of both adult wolves and noted that the 3-year-old male wolf was very hot compared with the breeding female, CPW said. Staff then noted the wolf had stopped breathing and had no pulse.
Wildlife staff tried to cool the wolf and revive it. About 20 minutes after the wolf was delivered to the CPW’s handling crew, a secondary crew that included a wildlife veterinarian arrived and confirmed respiratory and cardiac arrest, CPW said.
The agency’s veterinary gave emergency drugs to try to boost the wolf’s heart rate while performing CPR. The wolf was later pronounced dead.
The entire capture effort lasted 24 minutes, CPW said, and it took three minutes to chase the gray wolf before it was captured.
Staff have “combed through every detail” to try to determine why the male wolf died while the female showed no issues during the operation, Laura Clellan, CPW director said.
“The evidence and facts within the reports still don’t definitively point to a specific reason why the male wolf experienced such a high level of distress,” Clellan said in a statement. “We have a top notch professional team, and this situation has been tough on everyone involved. I have the utmost confidence in our staff and we will continue to work hard to achieve our mandate of restoring a sustainable population of gray wolves in Colorado.”
The capture process was “not abnormal nor suggestive of this level of stress response from the animal,” she added.
An independent third-party veterinary pathologist was in attendance for the necropsy and confirmed all of the exam results, CPW said.
Data from the female and pup’s collars show the two are still traveling together.