A dog whistle is a training tool designed to produce a very high tone, often near or beyond the range many people hear clearly. Online, recordings like this spread because viewers search for what a dog whistle sounds like, test whether pets react, or use it as a quick gag in pet edits. Its appeal comes from the contrast between a barely audible cue and an exaggerated on-screen reaction, which keeps it useful in prank clips, animal compilations, and short-form comedy.