Title: BBC - Earth - The tusks of narwhals are actually teeth that are inside-out
Headings: The tusks of narwhals are actually teeth that are inside-out
The tusks of narwhals are actually teeth that are inside-out
Content: Eric Baccega/NPL)
"This tooth is almost like a piece of skin in the sense that it has all these sensory nerve endings," says Nweeia. That is not seen in other mammalian teeth except when they are diseased. In all the encounters I've had with them, they are beautiful… and quite graceful
The narwhal tusk is "essentially built inside out," says Nweeia. Unlike our own teeth, it is soft on the outside, and gradually gets hard and dense on the inside. Nweeia's team showed that the tusk can sense changes in the salinity of the water, suggesting that it is a giant, antennae-like sensor. That is a little tricky to explain. " The tusk is most common in males and is only infrequently found in females," says Westdal. That suggests that it isn't "anything special required for survival", but is something to do with courtship and mating. They are not mutually exclusive explanations, says Nweeia. Tusks could be multifunctional: