When star-nosed moles are exploring, they release a stream of bubbles and suck them back into their noses. Why? Dr. Kenneth Catania believed that these mammals were making air bubbles to sniff the water -- odors could cross from the water and into the air bubble. To test his hypothesis, Dr. Catania made two paths, one leading to food. When the moles used air bubbles, they chose the path leading to food 85% of the time. When the moles couldn't use air bubbles, they chose the correct path only 50% of the time.
So what's this got to do with evolution? These noses are an example of how evolution works -- instead of reinventing a nose that could sniff odors in water, the star-nosed mole adapted its terrestrial nose to function in water. Certainly not perfect, but far better than not being able to smell in water at all.
Read the article by Carl Zimmer in the New York Times. The photo above is copyrighted by Dr. Catania
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