Narwhals are mammals. They have a layer of skin and a thicker layer of blubber beneath it. The skin is bluish gray with white blotches, although young narwhals are brown. Young narwhals are 5 feet long and can weigh 175 to 220 pounds. Adult male narwhals can grow up to be about 16 feet and weigh about 1.8 tons. Females are slightly smaller, about 13 feet, and weigh 1 ton. Narwhals communicate by making squeaks, clicks, and whistles. One of its most unusual characteristics is that the narwhal's more prominent tooth grows into a swordlike, spiral tusk up to 8.8 feet tall. It grows right through the narwhal's upper tooth. Females sometimes grow a tusk of their own, but is not as prominent as the male's. Some have an especially rare feature where they have two tusks, each tooth spiraling out.