Deer Whistle

These are small devices people mount on their motor vehicle in the belief that the sound generated by the device will somehow deter deer from entering the pathway of the traveling vehicle. Marketing claims suggest that air moving through the device will produce ultrasonic sound waves that warn deer of a vehicle's approach. The deer will then know to "stay clear" of the vehicle to prevent a deer-automobile collision. Their manufacturers promote them as "acoustic attention-getter" devices, alleging deer would react to the whistle by remaining still or clearing out of the way.

Evidence Based Study

In 1997 a study conducted by Dr. Ken Risenhoover at Texas A&M University, set out to define the hearing range of the whitetail deer. Using anesthesticized whitetail deer Dr. Risenhoover and his team attempted to define a deer's hearing range by attaching sensors to certain parts of the deer's head and interpreting the electrical responses obtained when sounds at different decibels and frequencies were introduced into the deer's ears. What this study discovered is that, based on the electrical responses, a deer's average hearing range is between 0.5 KHz and 16 KHz depending on the decibel level, with the maximum sensitivity in the 1 to 8 KHz range. That being said how does this hearing range compare to humans? Human Hearing Sensitivity

C.R. Nave with Georgia State University gives a brief synopsis of human hearing sensitivity in a 2005 Hyper Physics Concepts article. In this synopsis it is stated that human hearing sensitivity is rated between .02 KHz to 20 KHz. It can be assumed that these numbers are a fairly accurate representation of the averages found in the human hearing range, because unlike with the deer, a human can provide feedback on what they hear. Human hearing covers a broader range than that of a deer, therefore if you cannot hear the sound from the deer whistle the deer most certainly cannot.

The primary failures of the concept include the fact that few of these devices produce any appreciable sound and certainly not at an acoustic level that a deer is going to perceive. Very few of the deer whistles produced actually produce any sound at all. Even when ultrasonic sound is successfully produced by the whistle, due to the laws of physics it is a fact that ultrasonic sound does not carry any significant distance. And under the most ideal conditions even if the deer became aware of the sound coming from a deer whistle the deer would have no natural reflex to respond by flight or otherwise.

Plenty of research has been published to refute any claims of the advertising effectiveness. Those studies include those conducted by the Georgia Game and Fish Department, Insurance Institute for Highway Safety, Acoustical Society of America's Acoustics Research, the University of Wisconsin–Madison, and the Ohio State Police Department, all of which conclude that the deer whistle will have no influence over whether or not a motorist collides with a deer or any other animal.

Conclusion

You might observe an individual at the local truck stop purchasing a set of deer whistles along with some lottery tickets and a pack of cigarettes.