On hot days, they have their pick of swimming pools. They pluck avocados from backyard trees with impunity. When they amble down shaded streets, they are treated like celebrities: given a wide berth and photographed surreptitiously — except when they attract news helicopters.

They are California’s black bears, and there are, experts estimate, roughly 60,000 of them. Of the world’s eight bear species, including polar bears and giant pandas, the American black bear population is the only one that’s growing. In fact, there are more American black bears — omnivorous as raccoons and skittish around people — than bears of all other species combined.

In other words, the region’s bear population is thriving. It’s humans who have been left wrestling with how to adapt.

In recent years, black bears have expanded their range from remote mountains into suburbs that have increasingly blurred the line between city and wilderness.

Last year, officials with the state’s Department of Fish and Wildlife recorded 2,735 calls and reports about black bears. That’s up from 425 a decade prior, though they warned that the tally was skewed by changing tracking systems and staffing.

“Living alongside wildlife is a way of life in our foothill communities, but we’re seeing bears come into residential neighborhoods more frequently,” said Kathryn Barger, a Los Angeles County supervisor who represents the area. “Coming face to face with a 300-pound bear can be frightening, but in most cases these animals are simply looking to eat, cool off and move on.”

Researchers have found that a warming climate and wildfires may drive bears farther into human habitats. Across the country, similar shifts have prompted a cavalcade of wildlife tangles, like the peacocks that invaded a ritzy village in Florida, and the thousands of deer that overran an island off the coast of California.

But bears, with their fairy-tale associations and sheer size, stir unique fervor. And Californians, whose state flag immortalizes the image of a grizzly, which no longer roams in California, have the biggest bear population in the contiguous United States in their collective backyard.

“You’re going through that, like, roller coaster of fear and putting around cameras, and trying to haze them, and building fences and everything to protect ourselves,” said Brian Gordon, who lives in Monrovia, Calif., a leafy suburb tucked below the San Gabriel Mountains. “And after a couple months, realizing that it’s chill.”

Mr. Gordon and his partner started an Instagram account about what he describes as human and bear “co-thriving.” Their backyard pool has become a shrine to the “Pool Bear Life,” with a painting of a bear they call Maddie lounging in a hat and shades, a pink cocktail in her paw.

Others have a less whimsical take.

“I grew up seeing skunks, raccoons, possums,” said Ken Johnson, who has lived in Altadena, another Los Angeles County foothill community, for most of his life. In 2017, he saw a bear at his childhood home for the first time. It was sniffing around a bird feeder.

Then, in 2025, months after the deadly Eaton fire devastated Altadena, a mesh cover over Mr. Johnson’s crawl space was repeatedly chewed up. The day before Thanksgiving, a 500-pound black bear emerged.

“I was completely freaked out,” he said.

Mr. Johnson tried everything to evict the unwanted guest, who damaged ducts, causing a gas leak. He tried another crawl-space cover. He rigged cameras and a system to play the sound of dogs barking when the bear returned from brief forays.

Eventually, Mr. Johnson got in touch with the Bear League, a group based in the Lake Tahoe area, which helped him install electrified mats that give bears a little jolt to teach them to stay away.

The bear never came back.

Ann Bryant, who helped start the Bear League some 30 years ago, said that many Southern Californians were in similar straits.

“There are certain things they have to do, and there are certain things they cannot do, in order to live in bear country,” she said. Bear-safe garbage cans are mandatory in many Lake-Tahoe-area communities, so that trash day does not become a buffet. Businesses make the electrified mats that keep bears from denning in crawl spaces.

Bears, she said, should not be harmed because of “human error and human negligence.”

The stakes for the animals can be life or death.

This year, after a bear known as Blondie injured a woman who was walking her dog in Monrovia, state wildlife officials euthanized the bear, orphaning her cubs. Mr. Gordon and other residents hosted a vigil.

Arjun Dheer, the California Department of Fish and Wildlife’s black bear research coordinator, said that Southern California’s population had a complicated history: In 1933, a car salesman trucked a couple dozen from the Yosemite National Park area to the San Gabriel and San Bernardino Mountains. Park staff had been throwing garbage into “bear pits” to lure the animals to tourist areas. The businessman had the idea that the bears could become a similar draw farther south.

Dr. Dheer said that many of the estimated 2,000 bears in Southern California were related to those first 27 bears.

They are resilient, with an adaptable diet and flexibility in climes they can inhabit, he said. But the impulse to anthropomorphize bears by naming them and chronicling their antics risks encouraging human misbehavior. People who don’t know better may leave food out in hopes of attracting bears or fail to secure their homes and cars.

That, in turn, can make the animals and their offspring more dependent on human food sources, and thus more aggressive. This often ends poorly.

“We want to keep bears wild,” Dr. Dheer said. “A fed bear is a dead bear.”

John Harabedian, a state lawmaker who grew up in Sierra Madre, said he proposed legislation last year that would have directed the Department of Fish and Wildlife to more closely study Southern California’s bear population. It didn’t pass, largely because of the cost, but he plans to introduce similar legislation again.

Residents, he said, have backed a wide range of solutions.