Strange name or not, hagfish are actually pretty awesome

Hagfish use more than dirty looks to keep predators away

Quick notes:

  • Hagfish are eel-like underwater animals with skulls and without bones

  • Hagfish shoot fast-growing slime from their glands to deter predators

  • Scientists are researching the composition and creation of hagfish slime for human defense application

What is a hagfish?

Have you ever been called a hag? Maybe it’s time to start taking the name as a compliment. Hagfish are some of the coolest, most creative creatures in our oceans, so it might be time to start embracing the name.


Hagfish are kind of like eels. They’re slimy, slippery, and spineless. And no, that doesn’t mean that you can walk all over them. Unlike all other animals, hagfish manage to live and love without a vertebral column even though they have skulls (but no jaws).

There are over 76 different hagfish species, and while they all live in cold water, they’re found at nearly every depth of the ocean. And it’s not just the hagfish name or slimy exterior that makes the hagfish viewer squirmy, it’s their diet. Hagfish use bunches of tentacles around their mouth holes to find and burrow into their favorite dishes: dead bodies lying on the ocean floor. They don’t technically have teeth, but they have tooth-like keratin in their mouths that help them bite and eat their delicious and environment-friendly meals.

In addition to their carcass-eating, hagfish can also absorb delicious vitamins and nutrients from the water through their skin and into their boneless bodies. And that’s not all. When necessary (like when they need a bit of propulsion), hagfish can tie their tails and release the knot, allowing them to shoot through the water with surprising speed.

Spewing savage, swelling slime

The coolest thing about the hagfish isn’t its weird body or its diet of dead animals. Hagfish have an exceptionally inventive way of preventing predators from bothering them: they shoot out jets of rapidly expanding slime. When hagfish are attacked, mucus forms inside the animals’ glands. It is stretchy, strong, thin, and all-around amazing: it doesn’t just spurt out of the hagfish, it expands. Within seconds, the mucus grows to over 10,000 times its original size.

Scientists have been studying the hagfish and its incredibly increasing slime for decades, but it wasn’t until recently that they started to figure out how it actually works. Instead of shooting out like a giant clown pulling scarves out of their sleeves, hagfish slime unrolls more like a skein of yarn. When the first bits of mucus are discharged from the hagfish body, the water activates fibers within the mucus that start the whole process a-rolling: that is, the fibers start to unwind and create massive amounts of slime from the little bits of mucus. Gross and effective.


Why do we care?

First off, of course we care. These crazy little animals have developed a pretty amazing cure for being eaten, and as many as 12% of hagfish species are at risk of extinction. It might not be easy to readily apply their evolutionary knowledge to our own lives, but it’s still pretty interesting. And believe it or not, some scientists (and military personnel) are actually starting to wonder if we could bring a little hagfish into the human world.

Researchers (and the U.S. Navy) are currently investigating hagfish slime to see if there’s a way to create a synthetic version of this strong and growing slime. Scientists claim that there are a number of possible real-world applications, they just need to understand more about how the slime is created and discharged. Instead of battling robots and artificially intelligent beings, we might be headed into a future where we’re protected by hagfish slime. What a world.

A deeper dive — Related reading from the 101

-Divers make an incredible discovery in Lake Ontario: Science101

Not everything discovered underwater is slimy. Check out what this incredible team found at the bottom of a lake!

-Here’s to 400 more gruesome years, Greenland shark! Science101

This animal might not be as nice as the hagfish, but it will almost certainly live longer. The Greenland shark is large, long-living, and certainly in charge.