The hedgehog can hear sounds at higher frequencies than is possible for humans, dogs and cats, a potential breakthrough to protecting them from becoming roadkill. There are only a handful of critters than are cuter than the hedgehog, yet one-third of all mortality cases among local populations are attributed to car collisions. It happens so frequently that despite their rodent-like reproduction, these animals are now considered endangered by the U.S. Fish & Wildlife Service. Now, researchers have discovered for the first time that hedgehogs can hear ultrasonic sound waves as high as 85,000 hertz. Humans can hear up to 20,000 Hertz, dogs more than twice as many, and cats three times as much, but none can match the hedgehog’s sensitivity. Researchers are now investigating whether ultrasonic sound emitters mounted on cars, lawnmowers, and hedge trimmers could serve as effective hedgehog repellents. Blasting an ultrasonic note which only they can hear might dissuade them from attempting their long, slow road crossings that often end in disaster.
