Kenneth Catania, a biologist at the department of biological sciences at Vanderbilt University, Nashville, Tennessee in the U.S., says the star-nosed mole and the water shrew are able to smell food under water.
Writing in the Nature, he says this has come as a total surprise because the common wisdom is that mammals cannot smell underwater as it is not possible to breath in air, which carries smell to the olfactory epithelium, situated in the nasal cavity which identifies odor.
Catania began studying the possibility of mammals sniffing under water when he noticed the star-nosed mole he was observing blew a lot of bubbles while swimming. He and his team set up baits of earthworm or fish scent, covering it with a steel mesh, which prevented any of the star-nosed moles in the experiment sniffing the trail with any other contact, but only through the air bubbles that pass through. The rate and amount of air exhaled and inhaled were also measured.