The narwhal (Monodon monoceros), is a medium-sized toothed whale that, along with the beluga whale is one of two living species of whale in the Monodontidae family. It lives year-round in the Arctic waters around Greenland, Canada, and Russia. The most conspicuous characteristic of the male narwhal is a single long tusk, a canine tooth that projects from the left side of the upper jaw, through the lip, and forms a left-handed helix spiral. A tusk grows throughout life, reaching a length of about 5-10 feet in length. It is hollow and weighs around 22 pounds. About one in 500 males has two tusks, occurring when the right canine also grows out through the lip. Only about 15 percent of females grow a tusk, which typically is smaller than a male tusk, with a less noticeable spiral. Collected in 1684, there is only one known case of a female growing a second tusk.