Two big cats found dead in Santa Monica Mountains. Officials discover rare cause

Two big cats in the Santa Monica Mountains mysteriously died from an uncommon killer earlier this year, the Santa Monica Mountains National Recreation Area said.

An adult female bobcat and a subadult male mountain lion died from anticoagulant rat poison in the Simi Hills and Santa Susana Mountains, National Park Service biologists said in a Thursday news release.

It’s the first time in 23 years a bobcat has died from the poisons.

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

The bobcat, identified as B-372, had been in “good health” when she was captured in January, the National Park Service said. A necropsy report found brodifacoum, bromadiolone and diphacinone — all commonly used as rodenticides — in the bobcat’s liver.

More than 90% of bobcats studied in the Santa Monica Mountains have been tested after they die and were found to have exposure to some rat poisons, NPS said.

But it’s rare to see internal bleeding in bobcats.

“Since 2002, the leading cause of death for bobcats in this long-term study has been disease, specifically notoedric mange, followed by road mortality, according to Moriarty,” the news release said. “NPS biologists, in collaboration with researchers at UCLA, have found a strong association between the amount of exposure to (rat poison) and fatal mange disease, as well as significant effects of (rat poison) exposure on immune function and even gene expression in bobcats.”

B-372’s was “extremely emaciated,” showing signs of anemia and clinical symptoms of coagulopathy, indicating she may have been repeatedly exposed to rat poison, NPS said.

She spent a lot of her time in residential areas, which isn’t typical for adult female bobcats, according to NPS. That could have exposed her to more poison over a shorter period of time.

The mountain lion that died showed exposure to five compounds, including poisons.

“NPS researchers have documented the presence of anticoagulant rodenticide compounds in 26 out of 27 local mountain lions that they have tested, including in a three-month-old kitten,” NPS said.

This story was originally published August 27, 2020 at 3:46 PM with the headline "Two big cats found dead in Santa Monica Mountains. Officials discover rare cause."