Dog whistle

Dog whistles (left) adjustable, (right) fixed frequency

A dog whistle (also known as silent whistle or Galton's whistle) is a type of whistle that emits sound in the ultrasonic range, which humans cannot hear but some other animals can, including dogs and domestic cats, and is used in their training. It was invented in 1876 by Francis Galton and is mentioned in his book Inquiries into Human Faculty and Its Development,^[1] in which he describes experiments to test the range of frequencies that could be heard by various animals, such as a house cat. Dog whistles were first invented to explore auditory perception in animals and have since evolved into tools primarily used for dog training.^[2] The dog whistle has since evolved into a widely-used tool in dog training, with commercial developments leading to more specialized and efficient designs.^[3]

The origins of the dog whistle trace back to the late 19th century with the invention of the Galton whistle by Sir Francis Galton, a British polymath and half-cousin of Charles Darwin.^[4] Galton developed this device to study the range of frequencies audible to humans and animals, particularly dogs.^[5] The whistle emitted ultrasonic sounds beyond the upper limit of human hearing, allowing Galton to observe that smaller dogs could detect higher pitches than larger ones, and that cats responded to even higher frequencies, albeit with less enthusiasm.^[6] This innovation not only advanced the understanding of auditory perception but also laid the groundwork for the modern dog whistle used in training and communication with canines.^[7]

The upper limit of the human hearing range is about 20 kilohertz (kHz) for children, declining to 15–17 kHz for middle-age adults.^[8] The top end of a dog's hearing range is about 45 kHz, while a cat's is 64 kHz.^[9][10] It is thought that the wild ancestors of cats and dogs evolved this higher hearing range in order to hear high-frequency sounds made by their preferred prey, small rodents.^[9] The frequency of most dog whistles is within the range of 23 to 54 kHz,^[11] so they are above the range of human hearing, although some are adjustable down into the audible range.

To human ears, dog whistles only emit a quiet hissing sound.^[12] The principal advantage of dog whistles is that they do not produce a loud, potentially irritating noise for humans that a normal whistle would produce and thus can be used to train or command animals without disturbing nearby people. Some dog whistles have adjustable sliders for active control of the frequency produced. Trainers may use the whistle simply to get a dog's attention or to inflict pain for the purpose of behaviour modification.

The commercial development of the dog whistle, particularly by ACME Whistles, led to the introduction of adjustable frequency whistles and more compact designs, making them a key tool for dog training. These innovations allow trainers to communicate with dogs over long distances using frequencies inaudible to humans.^[13] The effectiveness of dog whistles, however, varies depending on the breed and individual dog's response.^[14]

In addition to lung-powered whistles, there are also electronic dog whistle devices that emit ultrasonic sound via piezoelectric emitters.^[9] The electronic variety are sometimes coupled with bark-detection circuits in an effort to curb barking behaviour. This kind of whistle can also be used to determine the hearing range for people and for physics demonstrations requiring ultrasonic sounds.^{[citation needed]}

• Infrasound

• Media related to Dog whistles at Wikimedia Commons