Traffic Poses A New Threat To Yosemite’s Famous Bears

4:18 minutes

state of science iconThis segment is part of The State of Science, a series featuring science stories from public radio stations across the United States. A version of this story, by Ezra David Romero, appeared on Capitol Public Radio’s Yosemiteland podcast. The article below originally appeared on NPR.  

People love seeing black bears when they visit Yosemite National Park in California. But encounters don’t always go well. The park has come up with a new way to keep humans and bears safe.

Fresno State University student Quiang Chang was walking recently with his friends along the rushing Merced River. It was his fifth time visiting Yosemite National Park, and he hadn’t seen a bear.

But if they appear, Chang said, “I probably would just quietly…just observe them and take a picture.”

Keeping a healthy distance from bears is exactly what park officials want people to do. But training the public to think this way hasn’t been easy, says National Park Service spokesperson Scott Gediman. Twenty years ago, human-bear encounters in Yosemite were very common.

“It was not atypical to have three or four vehicles broken into every night,” he says.

[The origin of the word “quark.”]

Bears would rip open car doors or smash windows in search of food. But others are craftier. One park visitor even took a video of a bear opening a car door with its paws.

In 1998, there were 1,600 encounters with bears. Now, there are fewer than 100 every year, says Yosemite National Park wildlife biologist Ryan Leahy. That’s because park rangers have worked to educate the public on storing food properly, and Leahy says they now use technology to track the bears.

Leahy works in a cabin on the edge of Yosemite Valley. He’s tracking bears online in real time using the GPS collars the animals wear.

In the past, he says, human interaction with bears often resulted in having to kill the animals. By using these tracking tools, fewer and fewer bears are killed. If a bear gets too close to people, Leahy’s team can scare it away, catch it or relocate it.

Tracking data from the past few years points to another trend: Bears are being hit by cars, and speeding is now their biggest threat. Leahy says 28 were hit in 2016, and many of them died. In 2017, 23 bears were hit and four died. As of June, three bears had been hit by cars, but that was before the busy season.

“You’re talking about 10 percent of our bears potentially being hit by vehicles each year,” he told me in 2017. “Just slowing down a little bit will give you that stopping distance required to prevent a collision.”

The key, he says, is education. His team has created an interactive map-based website where the public can track the lives of selected bears and see general areas where they’re hit the most.

[Is a dog’s pedigree all it’s cracked up to be?]

Leahy says the bears’ locations are delayed on the site so people aren’t able to track them in real time. On the site, park visitors can also learn about how to be safe if a bear is around.

“So what we want to do with this website in a positive way is engage people before they get here: ‘Hey, here’s the real story about black bears in Yosemite National Park,’ ” Leahy says.

He hopes the site means fewer midnight calls with a dented car and either a dead or wounded bear.

Segment Guests

Ezra David Romero

Ezra David Romero is a climate reporter for KQED News in San Francisco, California.

Segment Transcript

IRA FLATOW: Now it’s time to check in on the state of science.


IRA FLATOW: That’s local science stories of national significance, and our story this day comes from Yosemite National Park. You know it. It’s more popular than ever. In 2017, there were 4.3 million park goers. That’s about a million more than just a decade ago.

But as you know, with more visitors comes more traffic, more hikers, more search and rescue operations. A busier park means park statistics are trending upwards across the board, except in one category. And that’s the number of human encounters with bears.

Here to talk about what Yosemite does to curb the number of bear-human conflicts in the park is Ezra David Romero, environment reporter for Capital Public Radio in Sacramento, California, host of the station’s YosemiteLand podcast. Ezra, welcome to Science Friday.

EZRA DAVID ROMERO: Hey, thanks for having me.

IRA FLATOW: Now, we’ve all watched those cute movies on TV. Bears have been historically– when interacting with people, but they become a problem in the park, right?

EZRA DAVID ROMERO: Yeah, everyone loves these cute little black bears in Yosemite National Park. In 1998, there were about 1,600 bear interactions in the park. And today, there’s about fewer than 100 a year, and it’s all thanks to this program called Keep Bears Wild, which we’ll talk about it in a little bit. And there were so many for a good reason, like people used to feed bears in the park. They’d set up bleachers in Yosemite and put trash in the middle and watch bears eat them.


EZRA DAVID ROMERO: Fifty years ago or– Yeah.


EZRA DAVID ROMERO: Fifty years ago or so. So these bears got used to eating human food, so there’s this big campaign to have bears stop eating human food and keeping bears wild.

IRA FLATOW: So, OK, give us the formula. How have the Rangers been able to get the numbers down even when the park attendance is at the highest rate ever?

EZRA DAVID ROMERO: Yeah, so there’s about 300 to 500 bears in Yosemite, at any given time. They don’t know the bounds of the park or the map of Yosemite per se. They use a number of things. They have bear boxes, campgrounds along trails where people can put their food and smelly items and that’s to discourage bears from eating human food or deodorant and things like that. And they also put GPS collars around some bears and they tag them, and then the Park Service actively monitors bears.

They have a computer system on iPads. They can see where these bears are at and then, say if a bear gets near a campground or near Yosemite Valley, like the lodge or something like that, they can go and try to get that bear out of that area by using nonviolent tactics or loud noises. Or they can shoot like sandbags. Or ultimately, they can capture the bear and move it to another area of the park.

IRA FLATOW: So this has been successful, no?

EZRA DAVID ROMERO: Yeah, really successful. With 4 million visitors in the park every year and a growing bear population, they’re bound to have these encounters. But the number of bear encounters has decreased and the number of bears killed, because of these encounters have decreased as well. And last year in 2017, there were 23 bears that were hit by cars in the park. Cars and thus, humans entering this island per se in the middle of Yosemite are the biggest threat to bears. And so four of those bears last year died. And this year so far, four bears as of June were hit by cars and were unsure exactly about how many bears have died so far.

IRA FLATOW: So cars. Have they take any special measures for cars in the park?

EZRA DAVID ROMERO: Yeah, tons. They have this red bear dead bear program. So as you’re driving on the roads and the highways into the park, you’ll see yellow signs with black writing that say, speeding kills bears, with a red bear on them. And when you see that, that means a bear was killed there, and so they’re actively trying to get people to slow down. And they’re using these speed tracking signs in the park, starting this year. And they’re also increasing ticketing to get people to slow down because they don’t want bears to die.

IRA FLATOW: Yes, pull off the road and listen to Science Friday on the side there. Thank you, Ezra.


IRA FLATOW: Ezra David Romero with Capital Public Radio’s environmental reporter and host of the station’s YosemiteLand podcast.

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