If you are itchy, you have to scratch. But what if – like fish – you don’t have fingers to scratch Tuna fish are happy to risk their lives to get rid of their itching thanks to sharks. This is stated in the professional magazine PLOS ONE. After all, sharkskin is as rough as sandpaper.
Fish that live in the open sea – pelagic fish by the scientific name – are a popular host for parasites. The tuna is one of those (large) fish that is often harassed by parasites and they can sometimes itch. “The environment of pelagic fish also offers few options for removing the parasites (as well as the itching, ed.),” said researcher Chris Thompson.
But some fish are quite resourceful, according to research from the University of Western Australia. There they discovered that tuna, among other things, dare to swim exceptionally close to sharks in order to scrub the parasites from their bodies. Not only tuna do that, mackerel also like to risk their lives.
scratching post
After all, sharks turn out to be the perfect underwater scratching post. Their skin feels like sandpaper. In addition, sharks have a “slow and predictable tail stroke,” according to researchers. Other fish also appreciate that reliability.
And you might not expect it, but sharks care very little that other fish use them as scratching posts. They don’t even react when it happens.
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