We humans can see and hear in stereo. This is what leads to our 3D vision and allows us to find things easily because of our depth perception. Similarly our ability to hear in stereo allows us to roughly locate where a sound is coming from and how far away it is. But humans can’t smell in stereo, and it was widely believed that no mammal could naturally. That is until a study came out which indicates that the eastern mole, which is nearly blind, locates it’s food with the help of stereo smell.
Kenneth Catania, who led the research, said he came into it as a skeptic. “I thought the moles’ nostrils were too close together to effectively detect odor gradients.” Catania’s interest began when he found that the eastern mole could locate food just as quickly as its cousin, the star-nosed mole, which has a far superior sense of touch. In further tests he found that the eastern mole was remarkably quick at locating food placed in a radial chamber, indicating that they had a very sensitive sense of smell. In addition, Catania found that when he covered a mole’s right nostril, it veered to the left consistently, and when he covered the left nostril, it veered to the left consistently. This discovery is what indicated that the moles had stereo smell. Catania says this discovery “suggests other mammals that rely heavily on their sense of smell, like dogs and pigs might also have this ability”