Wavy facial hair helps seals find food

即使被蒙住眼睛和耳朵，海豹仍可以敏捷地捕獵，這是為什么呢？我們都知道海豹是有胡須的，那么這彎曲的胡須又在扮演怎樣的角色呢？它們是如何工作的？

Blindfold a harbor seal， clap headphones on its ears， and the keen hunter will still be able to track a distant fish， using its whiskers to detect the ripples made by its prey. Now， scientists have figured out the secret to the whiskers’remarkable sensitivity： their wavy shape. To simulate a whisker on a swimming seal， the researchers made a model hair and dragged it through a tank of water. A simple cylindrical whisker would have flopped around violently， much like the antenna on the hood of car does in the wind. But the curvy whisker model with its ellipse-shaped cross section barely wiggled， suggesting that the whiskers of a seal tearing through water at top speed would stay relatively still， the researchers report this month in a paper posted to the arXiv preprint server. Only when a second object was introduced into a tank， a simulated fish， did the model begin to twitch significantly. It vibrated in sync with swirls of water shed by the fake prey， sliding like a skier on a slalom course from vortex to vortex. Able to efficiently harness the energy of the whirlpools， the shapely whisker was set in motion even by slow-moving eddies generated by a faraway “fish.”