Hagfish are pretty disgusting creatures, but some of their most unsavory qualities also make them pretty fascinating. Consider, for example, what is perhaps the hagfish's most repulsive feature: the thick slime that it exudes whenever it is threatened or disturbed. Just a teaspoon is enough to turn a beaker of liquid water into a mucilaginous mass of gunk; so you can imagine what happens when it unloads a whole mess of the stuff into its surrounding waters.
But what is this slime for, exactly? For years scientists have assumed that the slime serves a defensive purpose, but nobody had ever seen the slime deployed in a natural setting. Now, a team of researchers in New Zealand have caught the Hagfish's defensive tactics in action. Not Exactly Rocket Science's Ed Yong writes:
The hagfish in the videos are attacked by sharks, conger eels, wreckfishes and more. In less than half a second, the predator's mouth and gills are filled with slime. It leaves, gagging and convulsing, slime hanging in long wisps from its head. Even voracious seal sharks turn tail. The cameras didn't follow the fleeing predators, so Zintzen doesn't know if they eventually died or if the slime dissolved away. Either way, the hagfish, uninjured and oblivious, just carried on feeding. Its defence is so effective that it can totally ignore the fact that a shark just tried to bite it.
Read more over at Not Exactly Rocket Science