A mountain lion that was captured in the parking lot of The Promenade shopping mall in Temecula died Friday morning while being transported to an intended release site.
Officials with the California Department of Fish and Wildlife said it is unclear what caused the mountain lion to die shortly after it was anesthetized with a drug that is widely considered safe for the large mammal.
“We’re not really sure exactly what went wrong. Something definitely did go wrong. They got the animal under control. It seemed to have effectively succumbed to the drug,” said Patrick Foy, a spokesman for the California Department of Fish and Wildlife. “On their way to release it, they came back out, and the animal had unfortunately died somehow in transit.”
Foy said that it is unusual for a mountain lion to die while using this method.
“Most of the time, it goes just fine, but sometimes it doesn’t. It wasn’t for lack of intent. In fact, these guys work very, very hard to make this successful,” Foy said. “It was a bad day for all of us, especially the lion.”
The mountain lion was a 100-pound adult male, estimated to be between 18 months and two years of age. An agency official who transported the lion’s carcass said that it appeared to be a healthy animal.
“There was nothing to indicate what may have caused death,” said Kevin Brennan, a wildlife biologist with the California Department of Fish and Wildlife.
Brennan said that any number of underlying factors could have led to the lion’s death but that an overdose of the drug is unlikely.
“It’s highly unlikely that the immobilizing drug would cause the death of a lion. They have extremely wide safety margins, and the darts we use aren’t even large enough to hold a small percentage of what would be considered a lethal dose,” Brennan said.
A wildlife biologist and veterinarian who regularly captures and anesthetizes pumas using the drug Telazol also said it is safe.
“The drug they used is the safest, in my view, that can be used in these circumstances,” said Winston Vickers, a UC Davis veterinarian and researcher.
Vickers said that numerous possibilities could have complicated the drug’s interactions and contributed to the puma’s death, including preexisting health conditions and high stress levels from the capture.
“Clearly, any time you anesthetize an animal or human, there’s risk no matter what drug you use and what the circumstances are,” Vickers said.
The lion was taken to the California Animal Health and Food Safety Laboratory for a necropsy. The results of that study are expected to be released next week.
Correction: An earlier version of this story incorrectly attributed a quote. We regret the error.