The Tusk: Male narwhals have a very long, hollow, spiral tooth that grows from the upper left jaw. The tusk is about 10 ft (3 m) long. Tusking is a behavior in which male narwhals rub their tusks together - perhaps determining dominance in the group.

Anatomy: Narwhals can grow to be about 16 feet (4.5 m) long (not counting the tooth), and weigh about 1.8 tons (1.6 tonnes).

Hunting and Diet: Narwhals eat fish, squid , shrimp, and other marine animals. They feed near the sea floor, deep under the pack ice of the Arctic.

Migration: Narwhals winter in deep-water beneath ice pack in groups of 5-10 animals; in summer they migrate to shallow, ice-free summer grounds where they congregate in larger groups.

Name: Narwhal means "corpse whale" in Old Norse; this is perhaps a description of their skin, which is bluish-gray with white blotches (young narwhals are brown). The scientific name of the narwhal is Monodon monoceros (meaning "one-tooth one-horn" in Greek). In medieval times, narwhal tusks that washed ashore were thought to be from the mythical unicorn.