where does a narwhal's horn come from
Narwhal The most conspicuous characteristic of the male narwhal is a single long tusk, a canine tooth[13][14] 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 1.5 to 3.1 m (4.9 to 10.2 ft). It is hollow and weighs around 10 kg (22 lb). 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[15] which typically is smaller than a male tusk, with a less noticeable spiral.[16][17][18] Collected in 1684, there is only one known case of a female growing a second tusk (image).[19]