A Narwhal's Tusk Is Actually a Tooth

The narwhal’s tusk looks like a horn, which is why the animal is so often compared to a unicorn. It is a tooth. NOAA Fisheries explains that narwhals have two teeth in the upper jaw. In females these teeth usually remain embedded in the jawbone. When a male reaches two or three years of age, the left tooth normally grows forward, out through the front of the jaw. The tusk spirals to the left, may grow up to 9.8 feet long and can weigh over 20 pounds. There are exceptions. Females with a tusk, and males with no tusk or with two, have occasionally been documented. NOAA Fisheries says the tusk mainly serves as a sign of status among males, and it may also be used as a sensory tool.