Bits & Bobs - Moles Can Smell in Stereo
Sandy Jack, Eastbourne
Most people have heard of ‘stereo sound’, but not many may be familiar with ‘stereo vision’, which helps many mammals discern depth. Seeing and hearing in stereo helps creatures living above ground, but moles need different equipment.
Biologist Kenneth Catania of Vanderbilt University conducted three clever experiments to see if the blind eastern American mole used ‘stereo smell’.
First, he built a chamber with trails that led outward from a central mole entry point, like a semicircle of wheel spokes. He placed a bit of earthworm, which moles love to eat, at the end of one of the trails and watched. On each trial, the mole first sniffed, moving its head back and forth, and then travelled straight to the food.
For the second experiment, Catania blocked the mole’s left nostril. This skewed the creature’s tracking accuracy consistently to the left. Similar results obtained when Catania blocked just the right nostril. Finally, Catania inserted tubes into both nostrils, but the tubes crossed so that each nostril accessed air that would usually enter the other nostril. This left the poor creature totally confused.
‘It was amazing. [The moles] found the food in less than five seconds and went directly to the right food almost every time. They have a hyper-sensitive sense of smell,’ Catania told Vanderbilt.
Stereo smell can only work if the nervous system can detect a difference in the strength of an odour entering each nostril. Considering the tiny distance between the nostrils, the precision and miniaturization of this biological chemical detector is mind-boggling.
Whether noticed or ignored, one can always detect the scent of the expert Designer behind any expert design. And these blind moles certainly emanate the fragrance of design.