On March 21, 2019, the mountain lion documented as P-47 was found dead in the Santa Monica Mountains. The lion’s GPS collar sent out a mortality signal and National Park Service biologists hiked into the central area of the mountain range to find him. With no visible wounds, the biologists suspected an unfortunate cause: poisoning.
It appears their early guess was correct. According to a statement by the NPS, testing on a sample of P-47’s liver showed that “the three-year-old male had been exposed to six different anticoagulant compounds, and a necropsy conducted by the California Animal Health and Food Safety Lab found internal hemorrhaging in his head and lungs.” The results indicated that P-47 succumbed to poisoning from an anticoagulant rodenticide, widely known as rat poison. In a statement, wildlife ecologist for Santa Monica Mountains National Recreation Area, Seth Riley, lamented the loss.
“It’s unfortunate to see an otherwise healthy mountain lion lost from what appears to be human causes,” he said. “In P-47’s case, it’s also a big loss because we don’t believe he had yet mated and passed along his genes, which would have been valuable since he had ancestry from north of the Santa Monicas.”
P-47 was a big cat, much like his father P-45, whose is believed to be dead. He weighed the same as his father, exactly 150 pounds, at his most recent capture and was tied for the largest among all the mountain lions that NPS have studied over the years.
Researchers do not know exactly how P-47 ingested the poisons, but they believe mountain lions are exposed through “secondary poisoning”; that the lions ingest the poison by consuming an animal that consumed the bait. This chain reaction can be wide, according to the NPS statement, describing a situation where a lion can “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.”
These poisons are highly lethal. Recent testing of P-64, another mountain lion the NPS was following and who died a few weeks after the Woolsey Fire, found six different anticoagulant compounds in his liver, including brodifacoum, bromadiolone, chlorophacinone, difethialone, diphacinone, and difenacoum. These same compounds were found in P-47’s liver, as well.
The scourge of rat poison is not just isolated to the harming of mountain lions. Across the country, researchers, farmers, and residential homeowners – both urban and rural – have discovered animals dead on their properties, including coyotes and owls, who ingested prey that had ingested poison.
The problem is so widespread that the U.S. Environmental Protection Agency performed a 2008 study analyzing the risk of 10 rodenticides for their impact on humans, wildlife and pets and re-evaluated their safety (along with their ecological impact). In a statement, the EPA announced that the review resulted in “tightened safety standards to reduce risks to humans, pets, and non-target wildlife.”
The Santa Monica Mountains National Recreation Area is doing their part to raise awareness to these poisons. In collaboration with their park friends group, the Santa Monica Mountains Fund, the groups launched an educational awareness campaign entitled #BreakThePoisonChain. The groups hope to raise awareness about the negative impacts of anticoagulant rodenticides and by encouraging residents to use alternative methods of rodent control.