by Meg Dorman, art by Charles Stubbs
We've all heard birds chirp and squirrels chatter. Apparently, small fish called herring also talk to their friends, though not with their mouths. Instead, a herring with something to say swims to the surface for a gulp of air, then blows the air out a hole in its behind. To the human ear, the burst of bubbles this produces sounds like a high-pitched squeak. But to a herring, it's hello. Scientists with a sense of humor have named this herring-speak Fast Repetitive Tick, or FRT, for short.
When scientists first heard the noise, they were puzzled about just why herring were breaking wind. Then scientists noticed that the herring usually made the noise in the dark and that they increased their FRTs when more herring were around. Conclusion: The FRTs were a way for herring, which swim in groups, to stay together in the dark. Because the high-pitched FRTs are impossible for most other fish to hear, the herring can say “Hey, where are you?” without alerting predators.
- How do herring make sounds?
- Why do herring make these sounds?
- Are these sounds low or high in pitch?
- If herring were larger, how might this sound change? Why?