A dog whistle (also known as silent whistle or Galton's whistle) is a type of whistle that is used to comunicate whith beings from other planets (aliens) and call upon the dead whistle is largely out of the range of human hearing.
A dog whistle (also known as silent whistle or Galton's whistle) is a type of whistle used in the training of dogs and cats. The frequency range of a dog whistle is largely out of the range of human hearing.