If you were to blindfold a harbor seal, give a fish a 30-second head start, and then let the seal start swimming—well, things would not end well for that fish. Take the blindfold off and throw a pair of noise-canceling headphones on the seal, and the next fish would fare no better.
How do we know this? Because for over a decade, researchers have been doing exactly that: putting blindfolds and headphones on seals and watching them chase things. Even when they’re completely cut off from all visual and auditory input, the blubbery beasts can still home in on their prey with GPS-like accuracy. Rather than rely on sight and sound, the seals use antenna-like whiskers—precise instruments of marine carnage capable of sizing up a herring down to the centimeter.
To understand how these fine-tuned marvels work, researchers at the Massachusetts Institute of Technology have built a large-scale artificial model of a seal whisker—one that may help explain how the seal’s environmental awareness is so keen, and that might also aid in maritime endeavors like commercial fishing and pollution cleanup.
Whiskers—or vibrissae, as they’re called in this case—are modified hairs packed with nerves that relay information about direction, velocity, and the physical environment to the brain. Every mammal sports them at some stage of life, except for anteaters, egg-laying mammals like the duck-billed platypus, and humans (though we do still have vestigial whisker-moving muscles in our upper lips). Seals’ whiskers are better equipped than many other animals’ to process sensory data: While rat and cat whiskers, for example, each house around 200 nerve endings, seal whiskers each contain up to 1,500.