Title: Narwhals: Mysterious Unicorns of the Sea | Live Science
Headings: Narwhals: Mysterious Unicorns of the Sea
Narwhals: Mysterious Unicorns of the Sea
The narwhal tusk
Where do narwhals live?
Narwhal life
Conservation status
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Content: In males, the right canine tooth remains in the skull and never grows out, while the left canine is the one that shoots out through the gums in a counterclockwise, spiral pattern to form the tusk. Rarely, both teeth protrude, giving the narwhal two tusks. Females are much smaller than males, growing to be about 13 feet (4 m) long and weighing about 2,000 lbs. ( 910 kg). Scientists consider the tusk a male sex characteristic, but about 15% of female narwhals also grow a tusk. Experts have long speculated about why narwhals have this bizarre, elongated tooth. Some theories suggest that the tusk is a tool for survival, as the whales could possibly use it to break up ice at the surface, spear fish for dinner or dig for meals in the seafloor. But the vast majority of female narwhals don't have tusks, and females tend to live longer than males. Therefore, experts think the tusk is probably not an advantage for survival but rather a primarily male sex characteristic that serves as a formidable weapon for competing with other males for mates. But the tusk may also have another purpose.