A mountain lion that was found dead last month in the Santa Monica Mountains in California had rat poison in its system, according to wildlife officials.
The lion, dubbed P-47, had no visible wounds when its remains were discovered on March 21 by biologists from the National Park Service (NPS) after the lion’s GPS collar sent out a mortality signal.
According to a statement by the Santa Monica Mountains National Recreation Area, a necropsy revealed that the three-year-old mountain lion may have succumbed to poisoning from anticoagulant rodenticide, commonly known as rat poison.
Biologists tested a sample of his liver and found that the animal had been exposed to not just one, but six different anticoagulant compounds. Internal hemorrhaging was also found in the head and lungs.
“Although it’s not known exactly how P-47 ingested the poisons, researchers believe mountain lions are exposed through secondary or tertiary poisoning, meaning that they eat an animal that ate the poisonous bait, such as a ground squirrel, or an animal that ate an animal that consumed the poisonous bait, such as a coyote,” officials said.
Researchers first marked P-47 when he was around four weeks of age at the den with a tracking device. He was later fitted with a GPS collar in January 2017 when he was 14 months old and weighed 108 pounds.
At his last capture in January 2018, he weighed in at exactly 150 pounds, which tied him for the largest among all the mountain lions in the history of the NPS study.
Biologists have documented the presence of anticoagulant rodenticide compounds in 21 out of 22 local mountain lions that they have been tested, including in a three-month-old kitten. Lab results for another mountain lion, P-64, who died a few weeks after the Woolsey Fire, also found six different anticoagulant compounds in his liver.
Mountain lions are large carnivores that can weigh up to 150 pounds in California. Males use ranges of up to 200 square miles, although in Southern California, roads and development can limit movement.
The National Park Service has been studying how mountain lions survive in an increasingly fragmented and urbanized landscape since 2002. Researchers have monitored more than 50 mountain lions in and around the Santa Monica Mountains. GPS collars provide detailed information about the animals’ ecology and behavior.