Whats the point of the narwhals tusk?
IT COULD be a jousting tool or an ice-breaker. It has even been attributed to the legendary unicorn. But the true purpose of the narwhal’s spectacular spiral tusk has remained a mystery. Now Martin Nweeia at Harvard School of Dental Medicine and his colleagues have come up with another explanation. They believe the tusk, which can measure up to 2.75 metres, could act as a sensor, helping the narwhal to survive in its Arctic home by detecting chemicals associated with prey, ice formation and salt concentrations. Two tusks taken from recently caught narwhals were examined under an electron microscope. This revealed a vast network of around 10 million fluid-filled tubules connecting the tusk’s central nerve to the surrounding water. Such tubules exist in human teeth, but are only exposed at areas of gum recession, where they cause extreme sensitivity. “The last place you would expect to have something so sensitive …
