Mice are somewhat wary animals and can be frightened by unfamiliar sounds or sounds coming from new locations. Most rodents, however, can quickly become accustomed to new sounds heard repeatedly.
For years, devices that produce ultrasonic sound that is claimed to control rodents have come and gone on the market. There is little evidence to suggest that rodents’ responses to nonspecific, high-frequency sound is any different from their response to sound within the range of human hearing. Ultrasound is defined as all frequencies greater than 20000 hz. This range is too high for humans to hear.
What is known about rodents and sound?
— Unusually loud, novel, or ultrasonic sounds, which rodents can hear, will frighten them and may cause temporary avoidance lasting from a few minutes to a few weeks.
What is known about ultrasonic sound?
— It is very directional and does not travel around corners well; thus, sound shadows or voids are created.
— Ultrasound does not travel very far. It loses its intensity rapidly as it leaves the source.
— Ultrasound has not been shown to drive established rodents out of buildings or areas, nor has it been proven to cause above-normal mortality in their populations. While it is possible to cause convulsions or permanent physiological damage to rodents with ultrasound, the intensity of such sounds must be so great that damage to humans or domestic animals would also be likely. Commercial ultrasonic pest control devices do not produce sound of such intensity.
Recent tests of commercial ultrasonic devices have indicated that rodents may be repelled from the immediate area of the ultrasound for a few days, but then will return and resume normal activities. Other tests have shown the degree of repellency to depend upon the particular ultrasonic frequencies used, their intensity, and the preexisting condition of the rodent infestation. Ultrasonic sound has very limited usefulness in rodent control. The advertising claims for many commercial devices are unsubstantiated by scientific research. Since commercial ultrasonic devices are often expensive and of questionable effectiveness, they cannot be recommended as a solution to rodent problems.
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Ultrasonic and Subsonic Devices for Pest Control
House Mice
