Moles Smell in Stereo: The Nose Knows

Moles may not be the prettiest mammals or the most interesting, but they sure can smell. New research from a scientist at Vanderbilt University shows that the common mole can smell in stereo.

Moles have a bad sense of eyesight, which caused it to evolve a highly developed sense of smell. It also needs to dig for its food, which means that it needs to be able to sniff out where it is.

Kenneth Catania, who conducted the research, placed a common mole in a semicircular arena with a chopped up bit of earthworm as bait. After wiggling its nose, the mole would beeline to the earthworm. Yet Catania wasn't satisfied with merely observing the basics of the mole's sniffing capabilities. He wanted to test just how powerful the mammal's nose was.

Catania first plugged one of the mole's nostrils with a short piece of plastic tubing. This caused the mole to veer off course in the direction of the open nostril when placed in the same arena with the earthworm. Then, Catania stuck small tubes into both nostrils and then crossed them. This essentially caused the mole to sniff orders from the right side with its left nostril and vice versa. The mole searched first to one side before finding the food, or missed the earthworm entirely.

These findings show that not only does the common mole have a powerful nose, it also can engage in bi-nostril smelling--also known as smelling in stereo. This research suggests that if moles can do it, other animals are likely to engage in bi-nostril smelling, as well. Dogs, pigs or other species with a powerful sense of smell probably have this capability.

The findings are published in the journal Nature Communications.