Aristotle, On the Parts of Animals, ii, 16, transl. by W.Ogle, London, 1882, p. 51:
"Just then as divers are sometimes provided with instruments for respiration, through which they can draw air from above the water, and thus may remain for a long time under the sea, so also have elephants been furnished by nature with their lengthened nostril, and, whenever they have to traverse the water, they lift this up above the surface and breathe through it."