Scientists Say: Hagfish

This fish is famous for its slime-making skills


This is not a bucket of worms. It’s a bin full of hagfish, fish that can squirt out a liter of slime in self-defense.

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Hagfish (noun, “HAG-fish”)

A hagfish is an eel-shaped fish that lives in the ocean. Hagfish feed on dead fish and other organisms that live on the seafloor. They have gills like modern fish but have cartilage instead of bones, no jaws and no eyes. Because of these traits, scientists thought that hagfish were “living fossils,” organisms that are similar to animals that lived long before fish evolved bones or scales.

Hagfish are indeed similar to ancient fish, but scientists now know that hagfish are in fact related to modern fish. They evolved bones and eyes long ago — and then lost them. Hagfish didn’t need them for their deep-sea lifestyle. But hagfish did keep a strange method of defense — slime. When attacked, a hagfish can squirt out a liter (or a quart) of slime, making any predator drop the fish in disgust. Scientists have found that hagfish slime is made up of unusually strong, yet lightweight, fibers. Some researchers are exploring how to make similar fibers in the lab. One day, these strong fibers might be used to make helmets, firefighting gear or even shark repellent.

In a sentence

Scientists are studying hagfish slime, trying to use its strong chemical parts for things like rope. 

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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