Conservationists have long advocated the reintroduction of cougars in areas of the United States where they no longer exist, and a new study might support this, but not for the reason you might think. Sure, they can help the environment by reducing the number of deer that eat saplings, but their reintroduction might also mean saving lives. If there are fewer deer roaming the landscape, a new study argues, it's possible the number of deaths caused by road collisions with the ungulates could also be cut.
The removal of large carnivores from the wild is a common phenomenon in the developed world. As farming and populations spread, man comes into increasing competition with large predators that occasionally prey upon livestock and even people. Yet only now are we starting to realize the profound impact that the extirpation of these animals may be having on the environment. Populations of their prey species have exploded, with deer becoming a particular problem.
They denude the landscape of plants, particularly saplings, which has been shown can have massive unforeseen impacts on the landscape itself, but they also pose a not inconsiderable threat to humans. In the US alone, over a million people have vehicle collisions with white-tailed deer, leading to around 200 deaths per annum, making the deer the most dangerous large mammal in the US. Researchers decided to look into the impact that a large predator, in this case the cougar, would have on the number of vehicle collision across the US, and have published their results in Conservation Letters.
By analyzing data from over 19 states, they found that if the big cats still stalked the forests, it could result in 155 fewer deaths per year, as well as prevent over 21,000 injuries and save around $2.3 billion over 30 years. While they note that the roaming of the large predator may cause human deaths in itself, they note that the number of people lost to the cats, estimated to be less than 30, would be far outweighed by the number of people saved overall.
The paper is careful not to make the argument for reintroducing the large predator, something that is highly controversial with the general public, but they do point out that the big cats are repopulating areas where they once roamed without our help anyway. The ecosystem service that they may provide in protecting people from potentially fatal accidents with deer on the roads could, they say, be another reason to let them return unhindered.
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