ELEPHANTS have a set of lungs unique among mammals, but for 300 years no one has known why. Now we have an answer: they are ideal for snorkelling.
Mammals have a fluid-filled space between their lungs and chest wall known as the pleural cavity. The cavity lets the lungs expand uniformly like a balloon within the irregularly shaped chest. But elephants don't have a pleural cavity. Instead, their lungs are surrounded by loose connective tissue. This feature was first noted in 1682, but has never been satisfactorily explained.
Now John West, a physiologist from the University of California, San Diego, says the anatomical quirk is an adaptation to life under water. He presented his theory last week at the International Union of Physiological Sciences conference in Christchurch, New Zealand.
Elephants can stay below the surface of the water by breathing through their trunks. If elephants had a pleural cavity, this ...
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