Don: Yael, have you ever tried smelling underwater?

Yael: Don, you can't smell underwater--you'd drown!

D: Not if I were a star-nosed mole! It seems that some land-mammals that sometimes      forage for food underwater, such as star-nosed moles and water shrews, may have      the ability to sniff out food sources while submerged.

Y: How do they do it?

D: While underwater, the moles exhale air bubbles onto objects they want to smell.      Then they quickly re-inhale the bubbles to carry the odor back through the nose.

     Kenneth Catania, a biologist at Vanderbilt University discovered the underwater      sniffs when he made high-speed video recordings of swimming star-nosed moles and      water shrews. The videos showed the moles and shrews were continuously blowing      and re-inhaling air bubbles from their noses when hunting for food.

Y: How did he know the animals were smelling, and not just blowing bubbles?

D: He tested the moles and shrews to see if they could follow a scent trail to find a food      source. He dragged an earthworm or fish across a piece of Plexiglas, and then      placed the odiferous plastic at the bottom of a water-filled tank. He found that both      the water shrews and star-nosed moles could accurately follow the invisible scent-      trails using underwater sniffing in over eighty-percent of trials.

Y: Wow, like little underwater bloodhounds!

D: Yeah! - maybe police departments should start training star-nosed moles to help      track underwater criminals!

Y: Oh Don...

D: Seriously though, the surprising finding in the moles and shrews has scientists      rethinking old assumptions that smell is a sense not used underwater. Perhaps we'll      find that other aquatic mammals are underwater sniffers too!  

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