Narwhal

Narwhal (Monodon monoceros), tusked whale native to the Arctic. The body of the narwhal is about 18 ft (2.5 m) long. It is a toothless whale except for the single spiral tusk, present only in males, on the left-hand side of the jaw, up to 8 ft (2.5 cm) long. The function of the tusk is unknown. The narwhal is hunted for the ivory of its tusk and for oil.