In horror flicks, creepy soundtracks are used to help scare the living daylights out of people. In a lab, two researchers used a similar device to freak out mud crabs in an effort to prove that they can hear.
The researchers placed the crabs in a big tank and piped in sounds commonly made by fish that eat them. The crabs were scared stiff. When mating calls and nest defense grunts of hardhead catfish and black drum fish played through an underwater speaker, the crabs didn’t dare venture out to dine on the juicy, defenseless juvenile clams that the researchers set out for them.
Just like in a movie theater, it was all an illusion. There were no fish; not even any swishing water. But for the crabs, it might as well have been the heart-pounding theme from “Jaws” or the shrieking violins in the “Psycho” shower scene, said A. Randall Hughes, an assistant professor of marine and environmental science at Northeastern University in Boston and a co-author of the study.