Why some whales can smell in stereo

ANY SCHOOLCHILD knows that a whale breathes through its blowhole. Fewer know that a blowhole is an adapted nostril, tweaked by evolution into a form more useful for a mammal that spends its life at sea. And only a dedicated cetologist would know that while toothed whales, such as sperm whales and orcas, have one hole, baleen whales, such as humpback and Rice whales, have two.

Even among the baleen whales, the placing of those nostrils differs. In some species they are close together. In others, they are much further apart. In a paper published in Biology Letters Conor Ryan, a marine biologist at the Scottish Association for Marine Science, suggests why that might be. Having two nostrils, he argues, helps whales smell in stereo.