LA's mountain lions become more nocturnal to avoid people. Does it come at a cost?

LOS ANGELES — Griffith Park’s late celebrity mountain lion P-22 took the night shift to avoid hordes of hikers, bikers and dawdlers who frequented his home in the heart of Los Angeles — and it’s a pattern replicated by other pumas in the region, according to a new study.

The move to a later schedule is an encouraging example of a species doing its part to coexist in a bustling megalopolis, according to researchers from UC Davis and other institutions who conducted the study.

But the temporal gymnastics they perform may come at a cost, experts said, consuming energy and limiting the amount of time they can spend on critical tasks such as hunting. And it may compound other urban stressors, like whizzing traffic and rat poison.

The study, published last month in the journal Biological Conservation, found that Southland mountain lions became more nocturnal and less crepuscular — i.e., active at dusk or dawn — in popular recreation areas.

To examine the impact of recreation on the lions, researchers used GPS and activity data gleaned from the tracking collars of 22 mountain lions roaming the Santa Monica Mountains and surrounding region between 2011 and 2018.

They also drew data from Strava, a popular app in which users publicly document runs, hikes and more to determine how much recreation was happening in each lion’s home range, and to test how it influenced the patterns and timing of their activity.

The “most nocturnal” puma in the study was the late P-41, who inhabited the Verdugo Mountains, a range bounded by freeways and development on the northeast edge of the San Fernando Valley, and a recreation haven. Ranked second was P-22, affectionately called the Brad Pitt of mountain lions when he stalked the Hollywood Hills.

Researchers wondered if mountain lions who were exposed to more recreation would become immune to it — and simply not care.

“We saw the opposite,” said Ellie Bolas, lead author and a PhD candidate at UC Davis.

“Seeing that mountain lions are flexible in their activity and sensitive to recreation is, I think, a reason we can feel optimistic that they’re willing to avoid us and want to avoid us,” she added.

Other institutions involved included Cal Poly Pomona, the National Park Service, UCLA, the University of Nebraska and Harvard Westlake High School.

The findings are good news for Angelenos worried about becoming a lion’s lunch — given that the cats are steering clear of people. And it helps explain how the apex predators manage to hack it in an intensely urban environment. Los Angeles is just one of two megacities in the world that are home to a big cat; the other is Mumbai, in India, where leopards prowl the streets.

So why are local lions rearranging their schedules for people? The new study notes that animals might high-tail it to areas where there are less people when they can. But in the greater L.A. metropolitan area, with more than 18 million people, even natural areas get gridlocked. So they adopted another strategy.

The National Park Service has monitored lions in and around the Santa Monica Mountains for more than 20 years, which is where the long-term data for the recent research came from.

“A major thing that we’ve been studying all along is the effects of urbanization and fragmentation on these animals,” said Seth Riley, study co-author and branch chief for wildlife at Santa Monica Mountains National Recreation Area, a unit of the park service.

The new study revealed that the lions’ timing shifts weren’t more pronounced on weekends when recreation spikes, contrary to what researchers expected.

There were also differences between the sexes, with female mountain lions found to be more active during the day and closer to sunrise. Researchers surmised that they avoid overlapping with male lions who will kill kittens in tow — and sometimes even the females themselves.

The least nocturnal puma tracked was P-13, a female with a home range in the central and western Santa Monicas.

Beth Pratt, California regional executive director for the National Wildlife Federation, said that while it’s good news that the charismatic cats are “coping,” there are likely tradeoffs.

“By switching their hunting strategy, it’s not ideal,” said Pratt, who was one of P-22’s biggest boosters. “It takes more energy, it doesn’t give them as many options, but the animals here are doing their part.”

People should pitch in, too, by minimizing challenges, she said. Panthers stalking the Santa Monica Mountains are imperiled by inbreeding because of freeways that essentially lock them in — and visitors with needed genetic diversity out.

“At a certain point they’re not going to be able to cope with all these challenges stacked up,” she said, pointing to threats such as cars and rodenticides — both of which took a toll on P-22. He was captured and euthanized in late 2022, deemed too sick to return to the wild because of injuries and infection.

One way to give lions “the edge” is by putting up wildlife crossings, said Pratt, who is a major force behind the largest such passageway in the world rising over the 101 Freeway in Agoura Hills.

The more than $90-million Wallis Annenberg Wildlife Crossing currently under construction is seen as a potential lifeline for the lions of the Santa Monicas. Without an outlet, the population is at risk of blinking out.

Pratt said the new study shows that actions as seemingly innocuous as how we site trails and enjoy the outdoors can impact the species — and that it would behoove us to consider our approach as we navigate a biodiversity crisis.

“It’s not that we shouldn’t do them, but how can we do them differently so that animals aren’t as impacted,” she said.

Bolas said there’s currently no research to tell us if the lions’ flexibility in the timing of their activity is also a cost to them, but that “it very well may be.”

Revelations from the study arrive as some Southern California and Central Coast cougars are at a crossroads.

California wildlife officials are poised to decide whether to designate six isolated clans of pumas as endangered or threatened species under state law.

The state Fish and Game Commission in 2020 granted the cougars who are roaming regions between Santa Cruz and the U.S.-Mexico border temporary endangered status as a candidate to be listed under the state Endangered Species Act.

A final decision is expected next year.