Famous for its unicorn-like single tusk, narwhals (Monodon monoceros) have inspired legends in many cultures and are still revered across the world. The smooth, white tusk is normally found only on males and is the result of extreme growth of the left elongated maxillary tooth that protrudes through the upper lip in a spiral form. It is believed by the majority of the scientific community that the tusk is asecondary sexual characteristic. Females occasionally grow a tusk and males have been seen with two, or none. The largest tusk ever measured was a massive 267 centimetres. Narwhals have a conical body shape and flexible neck with a mottled blue, black, grey and white body fading onto the underside. Older males can be distinguished by their white bodies with mottling only on the top of the back. The dorsal fin is just a low, inconspicuous ridge and the tail fin is concave. The narwhal's famous tusk is a hugely elongated tooth, and the largest ever recorded was over 2.5 metres long. Like elephants, narwhals are also hunted for their ivory tusks. Although sometimes seen in huge herds, sociable narwhals typically live in small groups and communicate through clicks and squeaks.
