An adult female mountain lion known as P-65 is the first cougar in the National Park Service’s two-decade research study to die from complications related to mange, NPS announced last week.
P-65 was found dead by biologists March 4 near a stream in the central Santa Monica Mountains. The 5-year-old big cat was suffering from a severe case of notoedric mange, a highly contagious skin disease caused by a mite parasite, the park service said.
“Her case of mange was severe, evidenced by hair loss and skin encrustation, especially on her face and head,” NPS said in a statement. “She was also extremely emaciated.
A subsequent necropsy conducted by the California Animal Health and Food Safety Lab revealed that the cougar had been exposed to five different anticoagulant rodenticides (rat poisons) and to bromethalin, a neurotoxic rodenticide, which may have caused the mange.
“We’ve had several radio-collared mountain lions that have contracted mange in the past, although in previous cases we were able to treat them with a topical anti-parasitic medicine,” said Jeff Sikich, the wildlife biologist who leads the mountain lion project.
“All of these animals recovered from their mange disease as best as we could tell from remote camera photos or later examination. However, in P-65’s case, we did not know about her disease until after she had died,” Sikich said.
Notoedric mange is a skin disease resulting from infection by mites. It typically affects wildcats such as bobcats and mountain lions, as well as other wildlife species like squirrels and rabbits.
Long-term NPS research on bobcats in the Santa Monica Mountains and Simi Hills has shown notoedric mange to be a major source of mortality since it was first documented in late 2001, the park service said.
“This research has shown a strong correlation between severe mange and the level of exposure to anticoagulant rodenticides,” NPS said.
In mountain lions, the park service said, six collared cougars and seven cougars overall have been documented to have died from the direct effects of the poisons, specifically bleeding to death internally after the toxicants prevented their blood from clotting.
Biologists said P-65 was an interesting cat to study.
She was first captured and collared in the central portion of the Santa Monica Mountains in March 2018. She survived the Woolsey fire in November 2018, and based on her GPS locations, her home range was found to be entirely within the overall burn perimeter, although during this time she largely used the southeast corner of the burn where there were some sizable, unburned islands.
In August 2019, P-65 became the second radio-collared female mountain lion to cross the 101 Freeway in the study’s history. She moved north into the Simi Hills from the Liberty Canyon area of Agoura Hills, where the Wallis Annenberg Wildlife Crossing is under construction.
Biologists believe P-65 most likely ran across the actual roadway. She eventually crossed the freeway again, returning to the central Santa Monica Mountains in the following weeks.
In the summer of 2020, P-65 gave birth to a litter of three kittens, two of which had mange but ended up dying on area freeways. mange, and remote camera photos later indicated that they had likely recovered. But both cats were killed on local roads after dispersing from their mother.
P-89 died on the 101 Freeway in Woodland Hills in July 2022, and P-90 died several weeks ago on Highway 33 just south of Ojai in Ventura County.
—Acorn staff report