Large predators reduce car accidents by keeping deer off roads
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- Cougars reduced deer-vehicle collisions by 76 percent on Washington's Olympic Peninsula, according to a study drawing on data from more than 500 camera traps and nearly 60 collared cougars
- Deer avoid road edges and the margins of towns when cougars are present, and shift to more daytime and less nighttime activity to evade their nocturnal predators, the researchers found
- Justin Suraci of the nonprofit Conservation Science Partners led the research, which was conducted in partnership with Native American communities running their own wildlife monitoring programs
- A 2021 Wisconsin study found that wolves cut deer-vehicle collisions by 24 percent, producing economic benefits 63 times greater than the costs of wolves killing livestock
- Liana Zanette of Western University in Canada called the paper "excellent" and said it clearly demonstrates that large carnivores benefit society "completely free of charge"
- Suraci said large predators may also reduce crop and garden damage from deer and curb the spread of diseases such as Lyme disease, benefits often overlooked in reintroduction debates focused on livestock losses
- The study was published in Current Biology (DOI: 10.1016/j.cub.2026.06.072)
Why it matters: The 63-to-1 economic return from the Wisconsin wolf study and the 76 percent collision drop on the Olympic Peninsula give wildlife managers a concrete cost-benefit case for predator conservation, undercutting reintroduction debates that focus on livestock losses while ignoring the safety dividend drivers and farmers quietly collect.
