Farmer’s Calendar for December 2016

December 10, 2015

The Star-Nosed Mole: An Animal That Thinks With Its Nose

A few weeks before Christmas, I found a dead star-nosed mole near our pond. A little bigger than an ordinary mole, it has an uncanny star-shaped nose. Circling the tip are 22 hairless tentacles that serve as the mole’s primary sensory organ.

Like other moles, it has weak eyesight, which is not much use belowground. Its nose, though, is covered with 25,000 sensory receptors called Eimer’s organs, which make it six times more sensitive than the human hand. Underground, the tentacles whirl around, touching objects near the mole with astounding swiftness: 12 objects per second. In a quarter of a second, the mole can identify an object, decide if it’s prey (worms, mostly), and eat it. Half the mole’s brain is devoted to processing this information; it literally thinks with its nose.

This mole also hunts underwater by smell. Its stellar nostrils emit tiny bubbles—5 to 10 per second—that pick up scent molecules. These the mole inhales. Not until this was discovered did scientists believe that mammals could smell underwater.

I walked home that day contemplating the magnificent weirdness of nature and the Magi, those ancient astronomers who also found their way through the darkness by following a star.

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