Mountain lion, bobcat in Santa Monica Mountains study die after ingesting rat poison: Biologists

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The National Park Service released this photos of P-76, left, and B-372, right, after they were found dead.

The National Park Service released this photos of P-76, left, and B-372, right, after they were found dead.

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A young mountain lion and a bobcat that were both part of wildlife studies in the Santa Monica Mountains have died after ingesting rat poison, National Park Service biologists said Thursday.

The death of the female bobcat, known as B-732, is just the second from the effects of anticoagulant rodenticides among the species in the study’s 24-year history, and the first in 23 years, according to an NPS news release.

Her carcass was found on June 20, beneath an oak tree in an Agoura Hills neighborhood.

A necropsy found brodifacoum, bromadiolone and diphacinone in the bobcat’s liver; the compounds included first- and second- generation poisons, according to the park service.

“We basically never see this in bobcats, so this is an important finding,” biologist Joanne Moriarty, who has studied bobcats for more than 15 years, said in the release.

In late January, at the time of her last examination, B-372 was found to have given birth at some point and in good health, according to Moriarty.

But at the time of her death, she was extremely emaciated, with bone marrow tests showing signs of chronic anemia — indicating likely clinical symptoms of coagulopathy, or uncontrolled bleeding, over a long period of time, the news release stated. That’s a sign of potential repeated exposure to rat poison compounds.

The bobcat apparently spent much of her time in residential areas, which is atypical for adult females, Moriarty said. But the 2018 Woolsey Fire devastated her natural habitat in the Simi Hills, causing her and other bobcats to flee the scorched land.

B-372 spent more time in neighborhoods and it’s possible that led to increased exposure to poisons, according to Moriarty.

Coagulopathy has been known to lead to deaths in mountains lions, coyotes and foxes in the study area, but rarely in bobcats.

“Generally when biologists have documented coagulopathy due to AR exposure in other species, the animals have appeared otherwise healthy, indicating a potentially large one-time, or short-term, exposure to the ARs sufficient to cause lethal coagulopathy,” the release stated.

That’s likely what happened to the mountain lion known as P-76, who was first captured and collared last November in an urban neighborhood in Northridge, according to NPS.

He was found dead just two months later, after his collar went on “mortality mode” Jan. 29. His carcass was recovered north of the Santa Susana Mountains, near the 118 Freeway.

The necropsy results, which just came back recently, showed he was exposed to five compounds —brodifacoum, bromadiolone, chlorophacinone, difethialone and diphacinone — including first-and-second generation poisons, biologists said.

P-76 is the third collared mountain lion to die of coagulopathy in the past two years, and the sixth overall in the study.

Anticoagulant rodenticide was also found in the livers of P-30, a 6-year-old male, and P-53, a 4-year-old female, after their deaths last year.

Rat poison has presented a challenge to the species’ survival in the territory, with anticoagulant rodenticide compounds found in 26 out of 27 local mountain lions that were tested for them.

Pumas and other predators are typically exposed to the toxicants through the food chain, either by eating an animal that consumed the poison, or another animal that ate the animal that ingested it, according to biologists. While exposure doesn’t kill all the big cats, it can have other negative impacts on their health.

“These two cases show us that different non-target species are continuing to be exposed to these toxicants, including an array of different poisons, with effects up to and including death from uncontrolled bleeding,” Seth Riley, the wildlife branch chief, said in the release.

Anticoagulant poisoning is one of the leading causes of death tied to humans for pumas that inhabit the Santa Monica Mountains and surrounding areas, the park service reports. Among bobcats monitored in the long-term study, the leading cause of death since 2002 had been disease, in particular notoedric mange.

“Between poisons, disease, and the massive Woolsey Fire, it has been a tough go recently for our wild cats in the park,” Riley said.

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