sound waves with frequencies above the normal human range of hearing
Hearing range
As dogs hear higher frequency sounds than humans , they have a different acoustic perception of the world . Sounds that seem loud to humans often emit high frequency tones that can scare away dogs . Whistles which emit ultrasonic sound , called dog whistles , are used in dog training , as a dog will respond much better to such levels . In the wild , dogs use their hearing capabilities to hunt and locate food . Domestic breeds are often used to guard property due to their increased hearing ability . So - called `` Nelson '' dog whistles generate sounds at frequencies higher than those audible to humans but well within the range of a dog 's hearing .
As dogs hear higher frequency sounds than humans , they have a different acoustic perception of the world . Sounds that seem loud to humans often emit high frequency tones that can scare away dogs . Whistles which emit ultrasonic sound , called dog whistles , are used in dog training , as a dog will respond much better to such levels . In the wild , dogs use their hearing capabilities to hunt and locate food . Domestic breeds are often used to guard property due to their increased hearing ability . So - called `` Nelson '' dog whistles generate sounds at frequencies higher than those audible to humans but well within the range of a dog 's hearing .