Scientists have found that archer fish can recognize the number of objects. The corresponding article has been uploaded to the bioRxiv preprint repository.

Splitters differ from other fish in their unusual way of hunting. They take water into their mouths, protrude slightly above the surface of the water and, with a sharp movement of the gill covers, spit out a stream into the insect. From this, it often falls into the water, where the fish eats it.

Now scientists from the University of Trent (Italy), led by Davide Potrich, decided to find out whether these fish are able to recognize the number of objects. They put the fish in a tank of water and placed a couple of discs on top. Dots were marked on the discs, and the researchers taught the fish to spit water into the disc with a certain number of them.

After that, the scientists showed the fish other pairs of discs, and found that they only spit at the one to which they were accustomed. To check that the fish remember the number, and not the external target, the researchers began to plot dots of different sizes, as well as use different discs - and this did not affect the result. If there were no correct targets among the proposed targets, the fish shot at the disc with the smallest number of points.

bbabo.Net