On the morning of September 23rd, 2020, California Highway Patrol discovered a mountain lion sprawled out on the 101 highway in Calabasas. Young and uncollared, the animal had been fatally struck by a car while attempting passage to the other side.
This is just the latest example of the dangers faced by our native big cats in the Santa Monica Mountains — the largest urban national park in the nation — where the arteries of growing human habitation have divided and strangled the natural habitat of the mountain lion.
A 2016 study published by the National Park Service and UCLA biologists found that, if current trends of genetic stagnation continue, the Santa Monica mountain lion population has a real chance of going extinct within 50 years. It came as a troubling surprise when, earlier this year, NPS researchers uncovered the first signs of this lack of genetic diversity.
P-81: a tell-tail sign
In March, Jeff Sikich, the NPS fieldwork lead tracking our mountain lions, came across subject P-81. The cat had some unfortunate quirks believed to be a manifestation of inbreeding: the tip of his tail kinked at a 90 degree angle, and having only one descended teste (a condition called cryptorchidism). Based on footage from wildlife cameras, it seems there may be at least another mountain lion with a crooked tail in the Santa Monica Mountains, though this cosmetic deformity seems inconsequential to them. The undescended teste, on the other hand, is worrisome as it has been linked to reproductive difficulties.
“This is something we hoped to never see,” Sikich said in a statement. “We knew that genetic diversity was low here, but this is the first time we have actually seen physical evidence of it.”
Los Angeles already has one of the least genetically-diverse mountain lion populations in California and across the West. A cautionary tale lies in what happened to the Florida panther population, where similar birth deformities foreshadowed a breeding depression that almost entirely wiped out the animal from the state.
The Florida panthers were revived when fresh blood was introduced into their decimated population, in the form of eight female panthers translocated from Texas. While our own fragmented mountain lion community is similarly in need of new genetic material, biologists have stressed that relocating cats from outside of the Santa Monica Mountains would provide only a temporary solution — without addressing the issues that brought about the current level of inbreeding, they would be importing new mountain lions indefinitely, and at great cost.
Progress on the Liberty Canyon Wildlife Crossing
A more permanent solution comes in the form of the Liberty Canyon Wildlife Crossing, a first-of-its-kind bridge project to reconnect the divided habitat.
On August 26th at its quarterly meeting, the California Wildlife Conservation Board voted to approve a $5 million grant for the crossing.
During a virtual presentation on September 23rd, Beth Pratt, Regional Executive Director of the National Wildlife Federation revealed some never-before-seen mockups of the project, which has been taken up by landscape architecture firm Living Habitats.
That the project is advancing, if slowly, is a big deal for the activists who have been fighting for it for decades. Once completed, the crossing could provide the model for addressing fragmentation issues all over the West.
A summer of kittens
Between May and August, thirteen kittens were found across 5 different den sites in the Santa Monicas. Three of these litters are suspected to have been fathered by P-63, an out-of-towner from the Simi Hills. He represents an important injection of new genetic material into the population.
Unfortunately, one of the litters was orphaned at a young age when their mother, P-67, succumbed to the effects of rodent poison. This prompted researchers to attempt a “fostering” of the two orphaned kittens, P-91 and P-92, by another female mountain lion who had also recently given birth.
The fostering didn’t stick, but the kittens now serve as ambassadors for the Santa Monica population at the Southwest Wildlife Conservation Center in Arizona, and researchers continue their attempts to better understand and nurture these apex predators in our collective backyard.
Turning the tide on rodenticide
The mountain lions and their human advocates gained a major victory in September when Gov. Gavin Newsom signed into law the assembly bill AB 1788.
Put forward by Westside Assemblymember Richard Bloom, it restricts the use of certain anticoagulant rodenticides. These increasingly potent poisons which operate by thinning the blood of their targets, resulting in uncontrollable and fatal bleeding, have been found in 85% of our tested mountain lions, and directly implicated in several of their deaths. They have also been wreaking havoc on state wildlife at large, particularly where larger predators are concerned.
The bill drew widespread support, garnering 10,000 signatories after it was reported that a bobcat and a mountain lion from a nearby population in the Santa Susanas had died from rodenticide poisoning in August.
In a statement, the governor wrote: “My father was a naturalist and a strong advocate for the preservation of mountain lions, and I grew up loving these cats and caring about their well-being. He would be proud to know that California is taking action to protect mountain lion populations and other wildlife from the toxic effects of rodenticides.”
And, of course, you — the public — can also take action to protect our neighbors in nature. Start by checking out P-22’s Wildlife Wonderland on October 23rd, an online festival celebrating Griffith Park’s most eligible bachelor.
Los Angeles is lucky to be home to one of the most incredible species on the planet (we share with Mumbai the distinction of being one of two major cities to harbor big cats), and we can only be enriched in our efforts to learn about and protect them.