Mountain Lion Was Exposed to Multiple Poisons, Tests Show

P-34 waking up after being collared by National Park Service researchers in December of 2014.

National Park Service

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News Release Date: November 10, 2015

Contact: Kate Kuykendall, 805-370-2343

THOUSAND OAKS, Calif. -- Lab results confirm that the mountain lion known as P-34 was exposed to multiple compounds of anticoagulant rodenticide, a form of rat poison. The subadult female, tracked as part of a National Park Service study, was found by a hiker in Point Mugu State Park on September 30.


“This is the latest indication that local wildlife continues to be exposed to these rodent  poisons,” said Dr. Seth Riley, wildlife ecologist for Santa Monica Mountains National Recreation Area. “We hope that P-34’s death will continue to raise awareness about how anticoagulant rodenticides work their way up the food chain, often with deadly effects.”


The lab found both first and second-generation anticoagulants in the animal’s liver. Recent legislation banned the retail sale of second-generation anticoagulant rodenticides, but they are still available for use by licensed applicators. First-generation anticoagulant rodenticides are widely available for purchase. The compounds found in P-34’s system were brodifacoum, bromadiolone, chlorophacinone, difethialone and diphacinone.


Suggestions on controlling rodents without anticoagulant rodenticides are available here.


Although it’s not known exactly how P-34 ingested the poisons, researchers believe mountain lions are exposed through secondary or tertiary poisoning, meaning that they consume an animal that ate the bait, such as a ground squirrel, or an animal that ate an animal that consumed the bait, such as a coyote. See infographic on how rodenticide can work its way up the food chain.


P-34’s death marks the study’s third case of mortality directly from rodenticide poisoning, though National Park Service researchers have documented the presence of the compounds in 12 out of 13 mountain lions that they have tested, including in a three-month-old kitten.


The California Animal Health & Food Safety Lab also found that P-34 had contracted a bacteria known as leptospira. Leptospira has been found in other mountain lions, but is more common in rats and canids. The bacteria can only be transferred to humans if there is contact with the exposed animal’s urine. Although she had some kidney disease from the leptospirosis, the bacteria did not appear to play a role in her death.  


P-34 made headlines last December when she was discovered lounging under a trailer in a mobile home park in Newbury Park. Earlier that day a resident snapped a stunning photo of P-34 walking in her backyard. Her sibling, P-32, was struck and killed by a vehicle on Interstate 5 this August after making a remarkable journey out of the Santa Monica Mountains.


The National Park Service began studying mountain lions in and around the Santa Monica Mountains in 2002. The purpose of the study is to determine how they survive in an increasingly urbanized environment.


Scientists are currently tracking 10 animals in the region (see map).


Santa Monica Mountains National Recreation Area (SMMNRA) is the largest urban national park in the country, encompassing more than 150,000 acres of mountains and coastline in Ventura and Los Angeles counties. A unit of the National Park Service, it comprises a seamless network of local, state and federal parks interwoven with private lands and communities. As one of only five Mediterranean ecosystems in the world, SMMNRA preserves the rich biological diversity of more than 450 animal species and 26 distinct plant communities. For more information, visit

Last updated: November 1, 2018

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