De sollertia animalium

Many observations like to these are made of the crocodile. But such is its skill in choosing a place for breeding, that no man can explain it by reason or conjecture. Whence it comes that the foreknowledge of this creature is imputed more to divinity than reason. For neither farther nor nearer, but just so far as the Nile that year will increase and cover the land, thither she goes forth and lays her eggs; which the countrymen finding, are able to tell one another how far the river will overflow that year. So truly does that animal measure for herself, that though she live in the water, she may lay her eggs dry. But the young ones being hatched, whichsoever of them, so soon as they are come to life, does not seize whatever comes next—either upon a fly, or a worm, or a straw, or a tuft of grass—with his mouth, the dam presently tears him to pieces with her teeth. But those that are fierce and active she loves and cherishes, according to the judgment of the wisest men, imparting her affection by the rules of judgment, not by the sway of passion.

The sea-calves also bring forth upon the dry lands; but then fetching out their young ones by degrees, they give them a taste of the sea-water, and presently lead them out again; and this they often do, till custom has made them bold, and brought them to love a sea life.

Frogs when they couple use a certain croaking invitation, which is commonly called ololygon; and when the male has thus enticed the female, they abide together all night. For in the water they cannot, and in the daytime they are afraid to engender upon the land, which in the night-time they do without control. At other times they croak more shrill and loud; and this is a sign of rain, and holds among the most assured prognostics of wet weather.