The yale was first written about by Pliny the Elder in Book VIII of his "Natural History": he describes the "eale" as a creature found in Aethiopia "the size of a hippopotamus, with an elephant's tail, of a black or tawny colour, with the jaws of a boar and movable horns more than a cubit in length which in a fight are erected alternately, and presented to the attack or sloped backward in turn as policy directs."