How do sharks sleep ?

The question of how the sharks sleep, for sure, someone will seem at least a bit strange. After all, many from childhood remember well that in fact sharks never sleep at all. This was once written in many textbooks and encyclopedias. However, today sites on the Internet are full of similar statements.

In the proof, there are usually two indubitable facts.First, sharks, unlike most other fish, do not have a swim bladder. Therefore, these wonderful swimmers, it turns out, can simply drown if they stop moving! This is true, but nothing can stop the coastal sharks from lying down right on the bottom.

And here comes the turn of the second argument. Surely you saw how the fish in the aquarium, frozen in place, work hard with the gills, driving water through them. It is in this way that cockerels and all kinds of carp with sardines breathe, absorbing oxygen from the water.