Science
L.A.'s mountain lions become more nocturnal to avoid people. Does it come at a cost?
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.
The study revealed that female lions were less nocturnal than males, possibly because males pose a threat to them and their kittens.
(National Park Service via Associated Press)
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.
Science
Lyrids Meteor Shower: How to Watch, Peak Time and Weather Forecast
Our universe might be chock-full of cosmic wonder, but you can observe only a fraction of astronomical phenomena with the naked eye. Meteor showers, natural fireworks that streak brightly across the night sky, are one of them.
The latest observable meteor shower will be the Lyrids, which has been active since April 14 and is forecast to continue through April 30. The shower reaches its peak April 21 to 22, or Tuesday night into Wednesday morning.
According to NASA, the Lyrids are one of the oldest known meteor showers, and have been enjoyed by stargazers for nearly 3,000 years. Their bright, speedy streaks are caused by the dusty debris from a comet named Thatcher. They appear to spring from the constellation Lyra, which right now can be seen in the eastern sky at night in the Northern Hemisphere.
The moon will be about 27 percent full tonight, appearing as a thick crescent in the sky, according to the American Meteor Society.
To get a hint at when to best watch for the Lyrids, you can use this tool, which relies on data from the Global Meteor Network. It shows fireball activity levels in real time.
And while you gaze at the heavens, keep an eye out for other stray meteors streaking across the night sky. Skywatchers are reporting that the amount of fireballs is double what is usually seen by this point in the year.
Where meteor showers come from
There is a chance you might see a meteor on any given night, but you are most likely to catch one during a shower. Meteor showers are caused by Earth passing through the rubble trailing a comet or asteroid as it swings around the sun. This debris, which can be as small as a grain of sand, leaves behind a glowing stream of light as it burns up in Earth’s atmosphere.
Meteor showers occur around the same time every year and can last for days or weeks. But there is only a small window when each shower is at its peak, which happens when Earth reaches the densest part of the cosmic debris. The peak is the best time to look for a shower. From our point of view on Earth, the meteors will appear to come from the same point in the sky.
The Perseid meteor shower, for example, peaks in mid-August from the constellation Perseus. The Geminids, which occur every December, radiate from the constellation Gemini.
How to watch a meteor shower
Michelle Nichols, the director of public observing at the Adler Planetarium in Chicago, recommends forgoing the use of telescopes or binoculars while watching a meteor shower.
“You just need your eyes and, ideally, a dark sky,” she said.
That’s because meteors can shoot across large swaths of the sky, so observing equipment can limit your field of view.
Some showers are strong enough to produce up to 100 streaks an hour, according to the American Meteor Society, though you probably won’t see that many.
“Almost everybody is under a light-polluted sky,” Ms. Nichols said. “You may think you’re under a dark sky, but in reality, even in a small town, you can have bright lights nearby.”
Planetariums, local astronomy clubs or even maps like this one can help you figure out where to go to escape excessive light. The best conditions for catching a meteor shower are a clear sky with no moon or cloud cover, sometime between midnight and sunrise. (Moonlight affects visibility in the same way as light pollution, washing out fainter sources of light in the sky.) Make sure to give your eyes at least 30 minutes to adjust to seeing in the dark.
Ms. Nichols also recommends wearing layers, even during the summer. “You’re going to be sitting there for quite a while, watching,” she said. “It’s going to get chilly, even in August.”
Bring a cup of cocoa or tea for even more warmth. Then lie back, scan the sky and enjoy the show.
Where weather is least likely to affect your view
Storm systems sweep across the country in early spring, and some will be obscuring skies tonight. But there will still be plenty of areas with clear skies, particularly in parts of the central United States.
“The best spot is going to be in the Upper Midwest,” said Rich Bann, a meteorologist with the Weather Prediction Center.
Minnesota, Wisconsin and Iowa will offer especially good sky-viewing weather and a beach on the Great Lakes could be a nice spot to look up at the stars.
But don’t expect to view the show from Chicago, as Illinois could see some thunderstorms. The weather will be better in the Northern and Central Plains, particularly the eastern Dakotas.
High, wispy clouds are expected over the Ohio and Tennessee Valleys and into parts of the Mid-Atlantic. But, Mr. Bann said, “you may be able to see some shooting stars through thin clouds.”
Clouds will be draped across much of the Southeast and the Northeast, though there could be some clearing in Florida, Georgia, the Carolinas and Virginia. Remember, the meteors could be visible all night long. If you look outside and see clouds, try again later.
Catching the spectacle will be challenging across much of the West, particularly from Washington into Northern California, where a storm system is bringing rain and snow. That system will move east overnight.
There are likely to be some pockets of clear skies at times across southern Nevada, northwest Arizona and southwest Utah, Mr. Bann said.
Amy Graff contributed reporting.
Science
FBI probes cases of missing or dead scientists, including four from the L.A. area
WASHINGTON — Amid growing national security concerns, the FBI said Tuesday that it has launched a broad investigation in the deaths or disappearances of at least 10 scientists and staff connected to highly sensitive research, including four from the Los Angeles area.
“The FBI is spearheading the effort to look for connections into the missing and deceased scientists. We are working with the Department of Energy, Department of War, and with our state and state and local law enforcement partners to find answers,” the agency said in a statement.
The FBI’s announcement comes after the House Oversight Committee announced that it would investigate reports of the disappearance and deaths of the scientists, sending letters seeking information from the agencies involved in the federal inquiry as well as NASA, which owns the Jet Propulsion Laboratory in La Cañada Flintridge, where three of the missing or dead scientists worked.
“If the reports are accurate, these deaths and disappearances may represent a grave threat to U.S. national security and to U.S. personnel with access to scientific secrets,” Reps. James Comer (R-Ky.), chairman of the committee, and Eric Burlison (R-Mo.) wrote in the letters.
President Trump told reporters last week that he had been briefed on the missing and dead scientists, which he described as “pretty serious stuff.” He said at the time that he expected answers on whether the deaths were connected “in the next week and a half.”
Michael David Hicks, who studied comets and asteroids at JPL, was the first of the scientists who disappeared or died. He died on July 30, 2023, at the age of 59. No cause of death was disclosed.
A year later, JPL physicist Frank Maiwald died at 61, with no cause of death disclosed.
Two other Los Angeles scientists are part of the string of deaths and disappearances.
On June 22, 2025, Monica Jacinto Reza, a materials scientist at JPL, disappeared while on a hike near Mt. Waterman in the San Gabriel Mountains.
On Feb. 16, Caltech astrophysicist Carl Grillmair was fatally shot on the porch of his Llano home. The Los Angeles County Sheriff’s department arrested Freddy Snyder, 29, in connection with the shooting. Snyder had been arrested in December on suspicion of trespassing on Grillmair’s property.
Snyder has been charged with murder.
There is no evidence at this point that the deaths and disappearances, which occurred over a span of four years, are connected.
A spokesperson for NASA, which owns JPL, said in a statement on X that the agency is “coordinating and cooperating with the relevant agencies in relation to the missing scientists.
“At this time, nothing related to NASA indicates a national security threat,” agency spokesperson Bethany Stevens wrote. “The agency is committed to transparency and will provide more information as able.”
Representatives from Caltech, which manages JPL, did not immediately respond to a request for comment.
Science
What’s in a Name? For These Snails, Legal Protection
The sun had barely risen over the Pacific Ocean when a small motorboat carrying a team of Indigenous artisans and Mexican biologists dropped anchor in a rocky cove near Bahías de Huatulco.
Mauro Habacuc Avendaño Luis, one of the craftsmen, was the first to wade to shore. With an agility belying his age, he struck out over the boulders exposed by low tide. Crouching on a slippery ledge pounded by surf, he reached inside a crevice between two rocks. There, lodged among the urchins, was a snail with a knobby gray shell the size of a walnut. The sight might not dazzle tourists who travel here to see humpback whales, but for Mr. Avendaño, 85, these drab little mollusks represent a way of life.
Marine snails in the genus Plicopurpura are sacred to the Mixtec people of Pinotepa de Don Luis, a small town in southwestern Oaxaca. Men like Mr. Avendaño have been sustainably “milking” them for radiant purple dye for at least 1,500 years. The color suffuses Mixtec textiles and spiritual beliefs. Called tixinda, it symbolizes fertility and death, as well as mythic ties between lunar cycles, women and the sea.
The future of these traditions — and the fate of the snails — are uncertain. The mollusks are subject to intense poaching pressure despite federal protections intended to protect them. Fishermen break them (and the other mollusks they eat) open and sell the meat to local restaurants. Tourists who comb the beaches pluck snails off the rocks and toss them aside.
A severe earthquake in 2020 thrust formerly submerged parts of their habitat above sea level, fatally tossing other mollusks in the snail’s food web to the air, and making once inaccessible places more available to poachers.
Decades ago, dense clusters of snails the size of doorknobs were easy to find, according to Mr. Avendaño. “Full of snails,” he said, sweeping a calloused, violet-stained hand across the coves. Now, most of the snails he finds are small, just over an inch, and yield only a few milliliters of dye.
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