Seals Possess Unique Whiskers To Track Prey And Navigate, New Study Reveals

Harbor seals have an enhanced ability to track prey using their antennae-like whiskers. Using large-scale, fabricated whisker models, researchers from Massachusetts Institute of Technology (MIT) have revealed a mechanism that may be responsible for the seals' super-tracking abilities.

Many marine animals, whales and dolphins for example, use echolocation. This is an internal sonar system that allows animals to locate objects based on reflected sound. But how are seals able to track prey when their sense of sight and smell are basically useless in marine environments? Their ability to do so rests in their unique whiskers, according to an MIT news release detailing a recent study.

For their study of seals, researchers reproduced seal whiskers using 3D printing techniques. Then, they examined the whisker response to various wakes and tested the whisker vibrations. As it turned out seals whiskers serve two main functions. For one thing, they remain still in response to a seal's own movements through the water, which allows them to precisely detect their prey. For another, they oscillate in a "slaloming" or zigzag motion in response to turbulence from moving objects. 

Slaloming actually allows the whiskers to extract energy from the wake, causing them to vibrate at the same frequency which allows seals to hone in on an object's size, shape and path. All of that makes navigating and track down their dinner a whole lot easier.

"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, a former MIT graduate student whose Ph.D. thesis formed the basis of this study, explained in the release. "Now we have an idea of how it's possible that seals can find fish that they can't see."

So what makes seal whiskers like sophisticated antennaw? It has to do with their shape: wavy with elliptical cross-sections that vary in size.

"It's marvelous to see this intricate pattern, it's not just a straight antenna– it's a perfect sinusoid," Michael Triantafyllou, a mechanical engineering professor at MIT, said in a statement.

The study of seal whiskers is intresting enough on it's own but holds some practical implications for underwater vehicles. Artificial whiskers could be implemented on underwater vehicles as low-power sensors, allowing researchers to better track marine animals or even sources of ocean pollution.

MIT's findings were recently published in the Journal of Fluid Mechanics.

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