De sollertia animalium

Then again we have heard Aristotimus relating how the land hedge-hog had a perception of the rising of the wind, and praising the trigonal flight of cranes. But for my part, I produce no particular hedge-hog of Cyzicus or Byzantium, but all the sea hedge-hogs in general; who, when they perceive a storm coming, ballast themselves with little stones, lest they should be overturned by reason of their lightness or carried away by the rolling of the waves, which they prevent by the weight of their little stones.

On the other side, the cranes’ order in their flight against the wind is not of one sort. But this is a general notion among all fish, that they always swim against the waves and the tide, and always take care lest the wind being in their tails should force their fins from their backs, and leave their naked bodies exposed to the cold and other inconveniences; and therefore they still oppose the prows of their bodies against the waves. For that while they thus cleave the waves at the top, the sea keeps their fins close, and lightly flowing over the superficies of their bodies, becomes less burdensome, besides that it suffers not their scales to rise.

This, I say, is common to all fish, except that fish which is called ellops; which, as they report, always swims with the wind and tide, not minding the erection or opening of the scales, which do not lie towards the tail, as in other fish.