Why Researchers Study Hagfish Slime

By on March 6, 2023
Sixgill Hagfish Sixgill Hagfish (Credit: Peter Southwood via iNaturalist CC BY-SA 4.0)

For some, hagfish are the embodiment of nightmares—however, for marine researchers, hagfish are an interesting creature to study. There are a few major points of interest associated with hagfish. First is the creature’s evolutionary patterns, or rather, the lack thereof. A 2019 study published by PNAS compared one of the oldest known hagfish fossils to its modern-day counterpart and found that the fish have remained largely unchanged for at least 66 million years.

From head to its paddle-shaped fin, the hagfish’s appearance is odd and, some might say, off-putting. The hagfish has anatomical structures that function like teeth, but the Alaska Department of Fish and Game explains that these parts are re-absorbed and re-grown. They use these teeth-like structures to dig into whatever fish they’re feasting on. The Smithsonian Channel has a video showing how the hagfish’s mouth opens up, as well as how the fish feeds on its prey.

Technically considered an invertebrate, according to the ADFG, hagfish are an outlier in the category as they are the only vertebrate with a skull but no vertebrae. In addition to its strange bone structure, tiny holes run along the side of the tubular hagfish body; some are for breathing, while others are used to produce slime. The fish produce copious amounts of slime to defend themselves against predators. The species’ ability to make slime is what attracts researchers to the eel-like animals.

Hagfish and Humans

Often referred to as “hagfish gel,” scientists at Switzerland University say that the gels the fish puts out are actually hydrogels, ultra-absorbent polymers with structures that allow them to hold and retain large amounts of water. If these are hydrogels, then the hagfish’s defensive mechanism may actually benefit humans as well.

Further research on the hydrogels revealed that they’re composed of long protein threads and mucus. Tapping into this mixture may make it possible to improve such human endeavors as tissue engineering, drug delivery and biosensor development.


While the gels have great potential, hagfish slime is too complex to replicate artificially. For now, at least—since the initial study in 2016, researchers have continued experimenting with the gels, testing other uses for the slime, and attempting to create an artificial alternative. For now, hagfish uses are still being explored.The ADFG states that the concepts being tested hold a lot of potential in the industrial and medical world. For example, some researchers have experimented with making fabric from slime fibers or using the slime to treat burns. Regardless, hagfish slime may be more valuable than previously assumed.

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