The Sweet Smell of Underwater Success

The star-nosed moles' special ability

• Hannah Schardt
• Apr 01, 2007

THE STAR-NOSED mole's most notable feature--its appendage-covered namesake--is even more extraordinary than it looks. Vanderbilt University biologist Kenneth Catania recently reported in the journal Nature that the semi-aquatic North American mole can actually use its sense of smell underwater--an ability previously believed off-limits to mammals. While investigating whether the moles, notoriously fast foragers on land, were similarly quick underwater, Catania made a startling discovery. "I noticed they were exhaling and inhaling little bubbles," says Catania. He stuck various objects to the bottom of a water-filled glass tank and filmed the moles as they exhaled bubbles--which touched the objects, picking up their scent--and then inhaled them once again, using the scent to identify which objects were edible. Catania has since duplicated his research with another semi-aquatic mammal, the water shrew, and believes other similar mammals may also be capable of underwater sniffing.