Home » cmvtitypt » Researchers find blind fish use novel type of navigational aid

Researchers find blind fish use novel type of navigational aid

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Researchers find blind fish use novel type of navigational aid (2014, April 7) retrieved 18 August 2019 from https://phys.org/news/2014-04-fish-aid.html Scientists have known for many years that fish have sensors on their flanks that allow them to feel what is going on in the water in which they are immersed. Now it appears that tetras living in a cave in Mexico have added to the sensory information they receive by causing changes to water pressure around them.The tetras are still the same species as the brightly colored fish found in aquariums across the globe, but because they’ve lived in absolute darkness for so long, they’ve lost both their coloring and their eyes. They don’t need either in their caves, as they live by eating bat droppings that fall into the water. But they also do something that has never been observed in any fish—they open and close their mouths, sucking in water which is pushed out the gills, and use the changes in water pressure created to help them recognize objects around them.Suspecting that something different was going on with the sucking motion the fish made, the researchers captured several samples and brought them back to their lab for study. There they put the fish in a tank with no food, but which did have five objects in it that the fish had to get around. After the fish became acclimated, the researchers moved the objects and then watched as the fish went to work. They noted that the fish suddenly began performing their sucking motion three and a half times more often. They followed up that experiment with another where they filmed the fish with a high-speed camera to help them count mouth action. They found that the fish very seldom sucked at the water when swimming at a distance from objects, or the wall. But when they came closer than 7 centimeters, the sucking frequency suddenly picked up, and when they moved to within just 1 centimeter, the sucking frequency occurred twice as often. It picked up again when moving even closer—up to six times as often.The researchers suggest that the novel type of navigational aid likely occurs in other fish as well, just none that are known right now. Explore further Journal information: Journal of Experimental Biology Researchers capture video of freshwater fish grabbing birds out of the airlast_img