n.
or narwal or narwhale
Toothed whale ( Monodon monoceros, family Monodontidae) of the Arctic, found in groups of 1520 along coasts and sometimes in rivers.
Narwhals are mottled gray, attain a length of 11.516 ft (3.55 m), and have no dorsal fin. They have only two teeth, at the upper jaw tip. The male's left tooth is a straight, protruding tusk, up to 8.9 ft (2.7 m) long, that is grooved on the surface in a left-handed spiral. It was prized in medieval times as the unicorn horn. The tusk is thought to have evolved as a sexual display. Narwhals eat fishes, cephalopods, and crustaceans. They are hunted by humans for their tusks and meat.