Deer horn

A deer horn, or deer whistle, is a (whistle) mounted on automobiles intended to help prevent collisions with deer. Similar devices are used in Australia to scare off kangaroos. Air moving through the device produces ultrasound or other high-frequency sound waves, intended to warn deer of a vehicle's approach. Deer are highly unpredictable, skittish animals whose normal reaction to an unfamiliar sound is to stop, look and listen to determine if they are being threatened. Scientific studies of these devices have indicated that they do not in fact reduce collisions.

Deer horn

A deer horn, or deer whistle, is a (whistle) mounted on automobiles intended to help prevent collisions with deer. Similar devices are used in Australia to scare off kangaroos. Air moving through the device produces ultrasound or other high-frequency sound waves, intended to warn deer of a vehicle's approach. Deer are highly unpredictable, skittish animals whose normal reaction to an unfamiliar sound is to stop, look and listen to determine if they are being threatened. Scientific studies of these devices have indicated that they do not in fact reduce collisions.