Hearing of dogs and cats is much more developed than hearing of humans. We can easily see this when we observe our animal: it sometimes reacts to things that are inaudible to us! What does a dog or cat actually hear as sound? What frequencies?
Humans hear sounds that have a frequency between 16 Hertz (low tones) and 20,000 Hertz (high tones).
Dogs and cats can hear sounds between 20 Hertz and 60,000 Hertz. They can therefore hear ultrasound that is inaudible to humans.
Other animals hear in even higher frequencies (up to hundreds of thousands of Hertz) such as bats, dolphins, orcas, whales … We speak then of detection by echoes.
A dog or a cat is able to hear sounds from far away: a noise that the human will not perceive at less than 4 meters, can be heard at more than 25 meters by the dog or the cat: footsteps on the stairs outside for example when his master comes in, or the engine of a car still far away on the street…
On the distinction of two different sounds, there is no precise study of sensitivity in dogs but the cat seems to have the same sensitivity as humans on low frequencies. It perceives variations of 1/4 tone in the mid frequencies (between 1000 and 20,000 Hertz) and 1/10 tone in the high frequencies.
Note that the frequencies around 20,000 Hertz correspond to the sounds emitted by small rodents, the natural prey of cats.
The auricle of dogs with erect ears or cats is cone-shaped and also very mobile, so it can be oriented easily and allows good localization of sounds.
The ears of dogs and cats are quite mobile because they are provided with many muscles.
The fact that the dog can hear ultrasound has a fairly practical application: the ultrasonic whistle.
The dog can learn the rule which applies to the sound of the whistle as to a classical sound (for the recall for example).
The advantage is that the sound is not heard by humans and will therefore be more discreet :).