Nature's Oddities Part 2: The Hagfish

"Truth must necessarily be stranger than fiction; for fiction is the creation of the human mind and therefore congenial to it."--G. K. Chesterton.

This quote is what inspired my Nature's Oddities series, and the hagfish could not be a better example of Chesterton’s paradox!

The hagfish belongs to the class Myxini, a Latin name that comes from the Greek work myxa, meaning mucus. I also think Myxini would be an excellent name for a Korean-built compact car. Move over Tiburon (shark in Spanish), the Myxini is coming to town!

The hagfish is very primitive, largley unchanged for perhaps 300 million year, but it has a scant fossil record. The first fossil was discovered in Northeastern Illinois (which is a rich palentological area. Braidwood, IL, near the powerplant's cooling lake, is an excellent spleunking place).



The oddness of the hagfish is tremendous, and it has definitely earned its place in my canon of oddball creatures. The hagfish is a vermiform (worm-like) creature found mainly in the Pacific Ocean (both the American and Asian sides), but it is also found in the Atlantic and in Scandinavian fjords. It’s a jawless vertebrate, like its more advanced cousin the lamprey. The hagfish has only a rudimentary skull and no actual vertebra. Unlike other creatures, its mouth horizontally articulates. It lives at depths of up to 4000 feet. It’s hermaphrodic, with both male and female gametes and genitalia, but it’s doubtful that they can self-fertilize (nobody has taken much interest in their reproductive idiosyncrasies, unfortunately). Hagfish are practically blind, and they can coil their body in overhand knots—an ability no snake, eel, lizard has. This ability comes in handy when it wants squirm free of its suffocatingingly think mucus, which it uses for predation, defense, and to keep its skin (which is used to make purses in Korea) healthy.

The hagfish has perhaps the most unusual way to subdue prey. Its extremely slow metabolism allows it to rest, motionless, for months on the ocean bottoms in silt and sand. Usually, only its head, which has a small olfactory opening, mouth, and respiratory opening, is exposed to the seawater. When it senses (by smell and vibration) a suitable victim, it swims into the passing fish though the mouth or gill opening and rapidly secrets its special mucus, which soon suffocates even large, predatory fish. It then eats its victim from the inside out, using its body as temporary shelter. It also feeds upon small annelid worms that live on the ocean floor and dead fish, as well.

Sounds like something out of a space alien movie, but it is indeed real.

Serious (as opposed to whimsical) scientists find the hagfish interesting because it has perhaps the most efficient and remarkable mucus of any creature. Mucus may not interest the average person much, but mucus is indeed important. Without it, any mammal would die from suffocation (it allows for gaseous exchange in the lung; insufficient pulmonary mucus is the primary cause of premature baby mortality). In the ocean, it is critical for keeping the right amount of the right salts inside the fish instead of diffusing into the water. The hagfish, however, has made its living off its mucus, so it is not surprising at all that it is really good at what it does. It is the professional mucus maker! Slimer is a hack by comparison.



Hagfish mucus is made of tiny protein fibrils very similar in structure to collagen (the protein that makes up most connective tissues in the human body, and about 27% of total protein by weight in adults). This alone makes it special, because most mucus is entirely made of mucin, the characteristic carbohydrate of mucus, water, a few salts, and anti-bacterial enzymes.

Another remarkable feature is that hagfish mucus 99.996% seawater, 0.0015% mucin and 0.002% threads. It is approximately 1000x more dilute than mammalian mucus. This is how the hagfish is able to make so much mucus so fast and with so little metabolic effort.

When the fibrils are released from the organism, mucin droplets deposit on them and form cross-links between the fibrils adding strength. Hagfish mucus is also one of the few muci (what the plural of mucus?) that functions in a wide range of temperatures (most muci functions best at body temperature of the organism). The strength, potency, and versatility of hagfish mucus have made it interesting to military and medical researchers. It is an example of the coveted, “space filling gel” which could be used to stop bleeding from massive wounds. Mucus also usually has anti-bacterial function, making it even more useful in this regard. I think it would be much better to develop some sort of weapon that would project slime on an enemy, immobilizing them. I am sure DARPA would abrubtly reject my proposal, but I can dream.

Bardack, D. (1991) First fossil hagfish (Myxinoidea): a record from the Pennsylvanian of Illinois. Science 254:701-703.

Gosline, J. M. et. al. (2005) Composition, morphology and mechanics of hagfish slime. Journal of Experimental Biology 208, 4613-4625