The frequency for ultrasonic dog whistles can range from 23 to 54 kilohertz. There are a variety of different dog whistle types, depending on training needs. Depending on the dog's breed, age and size, it may have various hearing capabilities, ranging from 40 to 60 kilohertz.
Even with high-frequency dog whistles, there is no guarantee that a dog will respond to it. Use of a dog whistle should be accompanied by training techniques, allowing the dog to familiarize the sound of the whistle with an expected behavior or reaction. Consistency is also key.
Knowing this, a regular whistle, such as what a human can easily hear, can be used as a training tool too. However, an ultrasonic dog whistle can be useful for certain situations, such as the final stages of training with work dogs, such as hunting or police dogs. Ultrasonic frequency whistles can especially be useful with hunting, because the human can gain the attention of the dog or command the dog to perform tasks (based on previous training with the whistle) without alerting or startling nearby game. Ultrasonic dog whistles can also be used for training dogs in highly populated areas, where a loud, regular whistle might disrupt or annoy nearby neighbors.