How Well Do You Know Narwhals?

The mystical nickname comes from the narwhal's tusk, which resembles a unicorn horn.

Those tusks are actually teeth, and narwhals have two! For males, one is an ivory tusk that comes out of his upper lip. Ladies can also grow them, but they’re a bit daintier in size.

Narwhals travel in pods. A covey is typically birds, a cloud usually insects, and a grumble is associated with pugs.

The prefix "Nar" means "corpse," and "hval" means "whale." "Corpse whale" is a reference to their skin color, which resembles a drowned sailor.

Though they're born blue-gray, narwhals change hues as they get older. Juveniles are blue-black, adults are a marbled gray, and old narwhals are almost completely white.

A team of researchers found that narwhal teeth are filled with a pulpy nerve tissue that seems to be sensitive to its surroundings.

With their tusks growing up to nine feet, narwhals are majestically massive and about as big as a bus, according to National Geographic.

Narwhals are hunted for their tusks, but their skin is also an rich source of vitamin C in a traditional Arctic diet.

During winter, narwhals dive up to a mile up to 25 times a day! The pressure at those depths is intense at 2,200 pounds per square inch, according to the National Oceanic and Atmospheric Administration. But narwhals can shut off oxygen or blood flow to noncritical body parts, and they have a conveniently compressible rib cage. Unlike dolphins, their muscles are built for endurance swimming, which helps conserve energy and, subsequently, oxygen consumption.

Because narwhals are so elusive, scientists haven’t been able to conduct much research about their mating habits — and that's lead to a lot of speculation about what those tusks are for, exactly. But a study published in Marine Mammal Science shows male tusks can be linked to the size of their testes, which is an indicator of fertility. So like peacocks, narwhals might rely on their appearance to attract a mate.