Ev'n slime begets the frog's loquacious race: Short of their feet at first, in little space With arms, and legs endu'd, long leaps they take Rais'd on their hinder parts, and swim the lake, And waves repel: for Nature gives their kind, To that intent, a length of legs behind.

Ovid, Metamorphoses, Book the Fifteenth (p. 163)