Eating something strange
And it slimes you good
Who you gonna call?
If you’re a fish, it’s too late to call anyone. You’ve been slimed by the hagfish you were trying to eat and that gooey, sticky stuff that looks a lot like the creature it came out of is about to suffocate you to death, turning you into food for … you guessed it … a hagfish.
The slime of the hagfish – a grey, eel-like, smelly, eyeless (more on that later) creature – has been known about for years. Its Latin name, Myxine glutinosa, comes from the Greek words for “mucus” and “glue.” But its slime’s use as the hagfish’s primary defense mechanism – including how it can get tangled in and then escape from its own slime – has never been studied. Researchers from Zurich in Switzerland took on the challenge and published their results this week in Scientific Reports.
Hagfish slime starts with a concentrated pre-slime that expands quickly in seawater – 90 milligrams can form over a liter of slime that stays slimy because its mucin (a glycoprotein in mucus) is long and threadlike. Once excreted onto a potential hagfish-eater, it bonds to its gills and suffocates the fish, expanding faster as the fish struggles. Since slime is tough to handle even for the slimer, the hagfish sometimes gets caught in it but is able to free itself by tying itself in a knot and pushing the knot down its eel-like body, thus scraping off the slime. Really!
The researchers convinced a hagfish to excrete slime out of its pores by giving it an electric shock while under anesthesia. They found that hagfish slime can change its viscosity depending on the force applied. As a predator gets slimed and struggles, the force makes it stickier and more difficult to get out of. On the other hand, the smooth movement the hagfish uses to slide a knot down its body thins the slime and makes it easy to slip out of.
Hagfish slime has a number of uses. It’s edible (can be used instead of egg whites – yummy), its fast growth makes it useful in stopping bleeding during surgery and it can be spun into a natural strong-yet-stretchy thread.
But wait … there’s more!
According to another study published this week in the journal Proceedings of the Royal Society B, a different research team (from the University of Leicester) studying the eyes of 300 million year-old hagfish and lamprey fossils discovered in Illinois found that these now eyeless creatures once had fully-functional eyes and lost them through reverse evolution.
The blindness doesn’t seem to bother the hagfish. With that kind of slime, neither do predators or Ghostbusters.