Pumas Might Be Making Your Drive Home Safer. When the Predators Are Around, Deer Tend to Avoid Roads, Preventing Some Collisions

In Washington’s Olympic Peninsula, the wild cats’ presence corresponded with a 67 percent drop in the likelihood of a deer-vehicle crash and a 76 percent overall decline in the number of wrecks during a five-year period, according to a new study

Sarah Kuta | Daily Correspondent

August 12, 2026 10:00 a.m.

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Although mountain lions are fearsome predators, the wild cats might also help keep humans safe in a surprising way.

When the large carnivores—sometimes also called pumas, cougars or panthers—are present, deer behave differently. Those shifts seem to reduce the ungulates’ encounters with vehicles, lowering the risk of dangerous deer-car collisions, researchers report in a study published on August 5 in the journal Current Biology.

At the study site in Washington state, they calculated that the presence of pumas corresponded with a 67 percent drop in the likelihood of a deer-vehicle collision and a 76 percent overall decline in the number of crashes during a five-year period.

“That is good news all around,” Liana Zanette, an ecologist at Western University in Canada who was not involved with the study, tells New Scientist’s Michael Le Page. “As though that weren’t enough, cougars also provide this service completely free of charge.”

For the study, scientists focused on the Olympic Peninsula, the large landmass in western Washington situated across Puget Sound from Seattle. The peninsula is home to numerous black-tailed deer, but it also has a well-established population of mountain lions. Researchers were curious to know whether the carnivores and their prey were affecting road safety.

So the team partnered with five Native American communities that had run wildlife monitoring programs. The tribal nations gave researchers access to data collected between July 2020 and June 2025 from 503 camera trap sites and 59 pumas outfitted with GPS collars. Together, the data revealed where deer and pumas were spending their time on the peninsula, as well as when they were most active.

The researchers also mapped wildlife-vehicle collision rates on the peninsula during the same period. Using data from the state’s department of transportation, they plotted 953 total crashes, which resulted in two human deaths, more than 80 injuries and an estimated $14.7 million in costs for vehicle repairs and human health-related expenses. Deer were responsible for 92 percent of those accidents.

Analyses revealed that when cougars were present, deer tended to head deeper into the woods, avoiding “habitat edges” like roadsides and the outskirts of cities and towns.

This behavioral shift makes sense, the researchers say, given pumas’ hunting tactics. The cats are “ambush predators,” study co-author Justin Suraci, an ecologist and director of the nonprofit Wildlife Conservation Science, tells Wired’s Molly Taft. “They prefer these sort of edgy, moderately fragmented habitats—roads cutting through the forest or lower-density development, pushing up against a forested area. [This type of habitat] gives them [the] opportunity to conceal themselves and attack the deer that’s foraging just outside the forest.”

When mountain lions were around, deer were also more active during the day and less active at night, when some of the most dangerous vehicle collisions occur. The researchers speculate this change also stems from the risk of cougar predation, since the cats primarily hunt at night.

The new study focused on a small part of cougars’ range, which spans large swaths of the Americas. But the animals might also be providing this “highly valuable ecosystem service” in other regions, the study authors write in the paper.

“This is useful for anywhere you have dense forest, roads and then more forest,” Fraser Shilling, director of the Road Ecology Center at the University of California, Davis, who was not involved with the research, tells SFGate’s Anna FitzGerald Guth.

The findings add more nuance to conversations about the pros and cons of mountain lions, especially for communities considering whether to reintroduce them.

Pumas can pose challenges for the humans living alongside them, including concerns about livestock losses and potentially dangerous encounters with pets and people. But these carnivores may also be providing tangible benefits to human communities—and scientists are only just starting to quantify them.

“This isn’t necessarily limited to road safety,” Suraci tells Popular Science’s Margherita Bassi. “The net value of these predation services in any given location remains very much an open question and one I think the conservation community is only beginning to explore.”

Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.