[Fr., from L. porcus, a hog; and piscis, fish.] This animal be-longs to the same genus as whales, and i s the smallest and most familiar of the cetacean mammalia. it is from 4 to 6 feet in length, of a dusky or blackish color on the back, and white beneath. It is closely allied to the dolphins, but has a shorter snout. When swimming, its round back looks like a hog in water. Porpoises swim in shoals, and drive herrings, mackerel, and salmon before them. They seek for prey near the surface, but also descend to the bottom in search of sand-eels and sea-worms, which they root out of the sand with their noses, as hogs do in the field for their food. From their blubber or flesh a fine oil is made, and from their skins leather for the uppers of boots and shoes.