Evolution

Moles have the ability to smell in stereo, according to new research.

Like many mammals, you have the ability to see and hear in stereo. This allows us to work out with precision where sights or sounds are coming from - if you hear a sound, your brain works out which ear is receiving more information and you conclude the sound's source is on that side. But whether any mammals have the ability to smell in stereo has been the subject of long-standing debate.

Until, that is, Kenneth Catania (Vanderbilt University, Tennessee) decided to test the Eastern mole (Scalopus aquaticus). He devised an arena containing 15 pits, arranged in the form of a semi-circle. One of these pits had a chunk of earthworm in. Every time the mole headed straight for the food (1). In a further experiment which involved temporarily blocking one nostril, the moles always veered off course in the direction of the unblocked nostril - if their right nostril was blocked, they went left (2). The last test involved putting crossed plastic tubes in their nostrils; in this condition moles often couldn't find the food at all.

The result took Catania by surprise. "I came at this as a skeptic. I thought the moles' nostrils were too close together to effectively detect odor gradients," he commented. With evidence of this ability in a mammals, future research can investigate which mammals possess it. "The fact that moles use stereo odor cues to locate food suggests other mammals that rely heavily on their sense of smell, like dogs and pigs, might also have this ability," said Catania.

Experiment videos:
1 (free-smelling) - http://bit.ly/VI0Qm7
2 (one nostril blocked) - http://bit.ly/Y9HroQ

To read the paper: http://bit.ly/Y9HroQ

Photo credit: Ken Catania.

http://phenomena.nationalgeographic.com/2013/02/05/stereo-mole-noses/

http://www.livescience.com/26871-moles-stereo-smell.html

http://news.vanderbilt.edu/2013/02/moles-smell-in-stereo/?utm_source=vuhomepage&utm_medium=newsbox&utm_campaign=moles-smell