The hagfish may well be the least charming fish in history, and you wouldn’t be wrong if you thought they looked like something straight out of a horror movie. They are the only known living animal that has a skull but no spine, and even though they have a skull they don’t have a jaw. Ummm…. What?! This leaves them with a gaping jawless mouth filled with teeth perfectly designed for stripping the meat from their prey. Their skin is loose fitting and only attached to their body in a few places, making them look like a fleshy nightmare sock (should we be calling them “nope socks”?). Despite their icky appearance, some creatures like sharks still think of the hagfish as a tasty snack, but this fish has a nasty trick up its sleeve. Hagfish can squirt a blob of slime that expands up to 10,000 times its original size in a fraction of a second, choking their predators and forcing them to flee. But the mechanism behind this rapidly expanding slime missile remained a mystery until just recently when scientists decided to get their hands… slimy. Through close observation and laboratory tests, the researchers found that the goo is not just a blob but is actually made of stringy fibers wound up like a ball of yarn. When you pull on the end of these threads, or what scientists are calling “skeins,” the ball quickly unravels and grows substantially in size. Based on the tests, scientists believe that the normal motion of seawater is all it would take to get these blobs to expand to their massive size. So it seems the hagfish can simply spit and swim away, leaving the water to do their yucky work for them.
Want to learn more? Visit https://www.sciencemag.org/news/2019/01/how-hagfish-launch-slime-missiles-swell-10000-times-size
Jan. 23, 2019