Silent dog whistles, also called Galton whistles after the inventor, Francis Galton, are useful whenever you need to give Rover a clear signal. Although you can't hear it, a blast on one of these small devices reaches your dog's ears easily, allowing you to communicate a training cue or simply get a distracted pooch's attention back where it belongs.
Why Do Silent Whistles Work?
Humans can hear sounds up to about 23,000 hertz, but Rover can hear far higher frequencies than you can. Silent whistles produce a noise between 23,000 and 45,000 hertz; it may sound like a low hiss of air to you, but your canine buddy perceives it as a shrill blast. Not all dogs respond equally to the sound of a silent whistle, but many -- especially small dogs -- seem to show an immediate interest in the noise, which may be reminiscent of the high squeaks made by tasty rodents in the wild.
Whistling for Attention
Because the noise made by a silent dog whistle attracts the attention of many dogs naturally, it can be a useful tool for getting Rover's focus back on you when he is distracted or doing something wrong. It's also a lot more dignified than yelling at the top of your lungs when you catch your beloved pup digging in the rosebushes at the furthest corner of the yard; the neighbors won't even have to know what's going on behind your privacy fence.
Whistling for Training
Rover's no dummy. Just as he can learn to respond to dozens of voice commands or hand signals, he can also learn to respond to a specific pattern of whistles with a specific response. A silent whistle makes a perfect training cue for dogs working in the field, far from their owners. It's clear, it's consistent and it carries over a distance. With careful training, Rover can become an expert, responding instantly to seemingly undetectable cues from you.
Whistling for Unwanted Barking
Several manufacturers offer collars that automatically produce an ultrasonic whistle whenever your dog barks. The theory behind these products is that the same whistle that distracts Rover from digging in the rosebushes can distract him from barking as well. According to the Humane Society of the United States, however, using such a method to control barking does not address the underlying issue and is therefore undesirable, since it does not reduce the feeling of stress that causes the dog to bark.