The seals are exceptional swimmers, capable of immersing even hundreds of meters in search of food and remain under water even for an hour thanks to the ability to regulate the amount of oxygen in the blood.
However, when they dive in depth, the seals find themselves in a hostile, cold environment, with little light and the cloudy water: how do they orient themselves in these conditions? To find out, a team from the University of Rostock, Germany, took a trio of seals and put them on the test by making them play video games: the results of the curious experiment are published on Journal of Experimental Biology.
How do you swim in the dark? The three fears of the experiment are common seals (PHOCA Vitulin), one of the most common species in the world. Capable of immerse yourself up to 500 meterswhen they swim deeply, dark and turbid waters often find themselves navigating: sand, phytoplankton and other microparticles reduce visibilityand make it difficult to swim on sight.
The team then invented a video game capable of testing the senses of the seals, to understand if they use the view even when visibility is reduced or if in those cases you use other senses, for example Using vibrisse. In particular, the game has made it possible to understand if the seals use the so -called optical flowthat is, what you see when you pass next to a moving object. In theory, analyzing the direction in which this object moves the brain is able to determine its direction of movement.
Video game champions. The video games proposed to the seals simulated three different situations: the open sea, in which a series of bright dots moved that imitated the phytoplankton and the other microparticles; The seabed, in which the dots moved rapidly towards the seals; and the surface of the water, in which the dots were instead above the head of the animals. The seals were trained to recognize the direction of the movement and to indicate it by crushing one of two large red buttons: when they crushed the right one, they obtained a reward.
Two of the three seals, who had already played similar games, immediately learned how the new one worked, and they guessed the (virtual) direction of movement without effort. A third, Miro, who had never seen a video game, needed six sessions to learn the rules: once done, he proved as good as the other two.
Obviously none of the three seals guessed in 100% of cases: it happens to everyone to make a mistake, perhaps by distraction. Of course, however, we know that even when the visibility is reduced the seals know how to go to swim while they swim, and indeed they use the “dirty” water to do it.
