See, harbor seals are really good at tracking down prey. You can blindfold them, and they'll still be able to follow the trail of prey that zipped by 30 seconds earlier. Scientists at MIT wanted to figure out how they manage that. According to their research, which was published recently in the Journal of Fluid Mechanics, slaloming whiskers are the key.
How does a whisker slalom, you ask? The whiskers have a unique, wavy shape. When a passing object (read: dinner) moves through the water and disturbs it, these whiskers start vibrating at exactly the same frequency. The researchers believe that allows the seal to determine the size, shape, and trajectory of the object.
Meanwhile, the unique shape keeps the whiskers from being disturbed by the seal's own movements. They vibrate based on external stimuli only, giving the seals precision and stealth.
The researchers tested this by 3-D printing giant replicas of seal whiskers and exposing them to different frequencies of vibration in the water.
“The geometry of the whisker allows for this phenomenon of being able to move very silently through the water if the water’s calm, and extract energy from the fish’s wake in order to vibrate a lot,” Heather Beem, who started the study as part of her now-completed PhD, said in a statement. “Now we have an idea of how it’s possible that seals can find fish that they can’t see.”
MIT professor Michael Triantafyllou, who was Beem's adviser, is pursuing possible technological applications for these artificial whiskers. He believes that sensors inspired by this well-adapted whisker shape could help aquatic vehicles track schools of fish or sources of pollution.