As marine biologists we consider it our solemn duty to celebrate and sing of the beautiful and charismatic animals that live beneath the waves (see for example here and here). But every now and then one has to face the fact that some animals are, well, just plain disgusting. Alas, not everyone can be a prom queen. And yet we all have our place in this world.
Exhibit A: The hagfish.
The hagfish (not be confused with the erstwhile punk band), named presumably in a less politically correct era, resembles nothing so much as a gigantic earthworm that forgot to shave this morning. Despite its straightforward name, the hag is not truly a fish at all, since it can’t be bothered to have a backbone, has only part of a skull, and is mostly soft and cartilaginous. A charming animal. In fact, it is one of the most primitive living relatives of the vertebrates—the group to which fishes and most large land animals belong, including us.
The hagfish is indeed so primitive that it doesn’t even have jaws, just a collection of raspy bits around its mouth. These are put to use burrowing into its even more dodgy diet, the carcasses of animals that have died and fallen to the seafloor. The hag uses its coiling back-boneless body and raspy teeth to work its way into, say, the blubber of a dead whale, and then eats its way out. I am not making this up. See the video:
Not much of a living one might think, but it appears to be a reliable one, since the basic body plan of the critter hasn’t changed much in a few hundred million years. Congregating in large masses in deep water, the hagfish is a survivor and a success story.
Despite its great evolutionary age, the hag has a few tricks up its sleeve. Its signature is its champion ability to produce slime, hence its other common name the “slime eel”. You gotta see this video (Warning: NOT immediately after lunch):
Another amusing parlor trick is the hagfish’s ability to tie itself into knots. One of the reasons suggested for this curious behavior is that it helps the animal rid itself of slime. Which raises the question why it is producing all that slime in the first place. One of the several mysteries that marine biologists have not yet worked out. But they’re on the case.
One might think, given its homely appearance and habits, that people would be perfectly content to leave the hagfish well enough alone. Evidently not. In Korea, almost 5 million pounds of hagfish meat are consumed each year. And (again, I am not making this up), hagfish skin is processed into “eelskin” boots, bags, and so forth. Indeed, due to its slow life history and low reproductive rate, hagfishes are vulnerable to overfishing, which has in fact strongly depleted their numbers in parts of Asia. It appears that nothing is safe any more.