Seal’s sensitive whiskers hold key to foiling fish escapes

Life under the waves can be a game of cats and mice. The seal is pursued by swimming fish, following awakening and rotating whirls that they leave, feeling weak whirlwind with their sensitive mustache. But fish can be deceived in fish.

Ivonn Krueger from the University of Rostok, Germany, explains that the avoidance of fish produces three aircraft of different sizes, when they rush, injecting in some directions almost simultaneously – at least two of which are formed in vortex rings, such as rings, which can confuse the seal. But maybe seals be able to see through a deception?

“The seal will have more chances to guess the direction of the fish escape if it can determine the difference between two vortex rings,” says Wolf Hank. To do this, the mustaches of the seals should have detected differences in the amount of tens of millimeters between two rotating vortex rings. But was it possible?

Krüger, Hanke, Lars Miresch and Guido Dehnhardt (University of Rostok) publish their discovery that prints can detect the differences in the width of the vortex rings in the awakening of only 17.6 mm, using only their mustache, which can help them detect control fish, in Journal of experimental biology.

Firstly, the team taught the seal of Habani (PhoCa Vitulina) named Filu, who lived in the marine scientific center, to immerse their heads when they with blindfolded eyes when they released a rotational vortex ring from a piston located on one side of the press of the press, sometimes visualizing a viral ring with uranium dye in the water. Then, shortly after, they released a smaller or more vortex ring on the other side.

Phil had to decide which of the vortex rings was more based only on the sensation, when the water was spinning along his mustache, knocking one of two green balls on both sides of his head so that the scientists learned which side made a larger vortex ring and receiving a reward for the fish when it was right. “It took him quite a lot of time to understand the concept of various sizes of the vortex ring,” says Kruger.

Initially, the team checked the ability of Phil to distinguish the vortex rings that vary in the amount of 89.9 mm, to 45.8 mm – with the least difference of 17.6 mm – and the Phil was surprisingly successful (much higher than 80%), correctly choosing the side with the largest virtual appearance, using only its upeers.

But in order to be sure that Phil could really distinguish vortices of different sizes, the circle changed the way that the vortices were paired, so one of the smaller whirlwinds (68.0 mm), which Philu had previously ignored, was a larger whirlwind. And he still chose it.

After several months of patience and thousands of trials, they switched between the whirlwinds, the circle and colleagues were convinced that the seals of the harbor were able to distinguish between Vorthy rings This differs in size by only 17.6 mm, using their sensitive mustache.

But what does it mean for fishing? When the second aircraft, produced by a running fish, which injects in the opposite direction from the movement of fish, is accompanied by a larger vortex ring, and Phil can distinguish between boar vortices that differ only for 17.6 mm, Krüger and colleagues believe that it is very likely that the compaction can see the attempts of fish.

Sensitive seals mustache could simply detect the largest rotating whirlwind, generated as fish An attempt to escape and immerse yourself in the opposite direction to move and strand a fish shoot.