Hagfish are far from cuddly. The pinkish eel-like creatures sport rows of toothy spikes around their mouth, allowing them to burrow into decaying animals like worms in dirt. But these oddballs are amazingly successful, able to inhabit a range of environments and have done so relatively unchanged for more than 300 million years. One of the keys to their success is an ingenious defense mechanism: slime.
When attacked by predators, these wriggly critters activate their slime glands, clogging their enemies’ gills with gelatinous glop—a gooey pepper spray of sorts that lets them escape unscathed. Few marine creatures are equipped to challenge this slimy defense system. Now, the U.S. Navy hopes to tap into the power of the slime, synthesizing an artificial version to keep their divers safe in the deep.
If you can get over the “ick” factor of the hagfish slime, the marine gelatin has many desirable properties. The goo is made of microscopic filaments, and though the skinny threads are thinner than a blood cell is wide, they are surprisingly strong. They’re also extremely long, extending nearly six inches. But the property that has intrigued many researchers—and caught the eye of Navy scientists—is the slime’s capacity for expansion. Once the slime mixes with water, it can grow to nearly 10,000 times its initial volume, according to Ryan Kincer, a materials engineer with the Naval Surface Warfare Center in Panama City.
