Evidence Moles Can Smell in Stereo

http://www.sciencedaily.com/releases/2013/02/130205123011.htm

Feb. 5, 2013

It has been a long debated scientific topic and new research may suggest that many mammals may smell in stereo. It is known that many mammals, including humans, hear in stereo, but the ability to smell in stereo may explain why certain animals, such as moles, are able to rely on their sense of smell to locate their prey.

A recent study, published in the journal “Nature Communications” on February 5^th, shows that moles do in fact use stereo sniffing to navigate and locate its prey or predators. The study was done by Kenneth Catania, a professor of biological sciences at the Vanderbilt University. Catania admitted that he was a skeptic at first. He believed it was impossible for moles to smell in stereo because of how close together their nostrils are. He also added, "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,"

Catania’s initial interest in moles started when he was studying the star-nosed a mole. The star-nosed mole is a close relative of the common mole however it uses tentacles surrounding its nose to detect food. Because the common mole is blind and does not posses a set of tentacles to help find it’s prey, Catania rightly assumed that the common mole’s ability to find prey was a lot worse than the star-nosed mole. As well as being blind, the common mole also has a poorly developed sense of touch. "I expected the common mole, which is virtually blind and doesn't have a very good sense of touch, to be a lot worse than the star-nosed mole. So I was quite surprised when they turned out to be very good at locating prey. At the time, I figured that they must be using their sense of smell, but I didn't pursue the matter."

His study consisted of a 180-degree area around an entrance where the mole would enter. The surrounding area consisted of multiple food wells with pieces of earthworm inside of them. He ran multiple trials with the food in different food wells. He found that the moles could detect the food and crawl over to it in less than 5 seconds.

He conducted a follow-up study where he placed the food directly opposite the entrance. He found that the moles went straight for the food, however when he covered the left nostril of the mole he found that it went to the right of the food. When he covered the right nostril he noticed that the mole went to the left of the food.

I found this article very interesting because it ties in with the topic that we are doing in class: evolution. Because the mole is virtually blind and has a limited sense of touch, its sense of smell is extremely developed. The mole must have lost its sight through many years of living underground where vision was unnecessary. As a result, moles have huge claws that help them burrow tunnels underground and an extremely developed sense of smell to help locate prey.