Hagfish slime: The clothing of the future?
The jawless, spineless hagfish is a primitive creature that lives at the bottom of the ocean and dates back as far as 500 million years - but it exudes a very special slime, which could provide the clothing of the future.
Hagfish are not the most glamorous of creatures.
They slope around on the deep, dark ocean floor, scavenging for food. Dead whale is a favourite.
But they do have a trick up their sleeve, or rather tucked within their snake-like body - abundant, highly-condensed slime.
A hagfish has no jaws, and its slime serves as a valuable form of self-defence.
Researchers recently filmed what happens when a shark bites a hagfish - its mouth and gills are quickly covered in slime. The shark has to back off, or face a slimy suffocation.
"They're maybe not the prettiest of creatures to work on, but I have a lot of respect for them," says Tim Winegard, a researcher at the University of Guelph in Canada, studying the fibres found in hagfish slime.
"These guys have been around through just about everything," he says. "They're a winner in terms of outlasting dinosaurs and many, many mass extinctions."
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Dinosaurs became extinct about 60 million years ago but a hagfish fossil - complete with evidence of slime-producing glands - has been found dating back 330 million years.
A hagfish has about 100 of these glands, or invaginations, that run along the side of its body from which they exude a milky, white substance, comprising mucus and thread.
When this gets mixed with seawater, it expands, creating huge amounts of clear slime, composed of very thin - but super-strong and stretchy - fibres.
When you stretch the fibres in water and then dry them out, they become silky.
The largest species of hagfish can reach about 4ft (1.2m), though most are around 1ft (30cm) long.
But despite their small size, a single hagfish has hundreds of kilometres of slime thread inside it.
Scientists believe hagfish slime or similar proteins could be turned into tights or breathable athletic wear, or even bullet-proof vests.
For years, scientists have been looking for alternatives to synthetic fibres like nylon and lycra, or spandex, which are made from oil - a non-renewable resource.
Hagfish slime has the potential to provide a natural and renewable alternative.
But first, the experts need to work out how to increase the slime production. It's unlikely that we will ever see massive hagfish farms. Hagfish don't seem to respond well in these conditions.
What we know about hagfish…
- There are more than 80 species of hagfish - but despite the name, they're not really fish
- They are considered craniates, and have a hard structure that surrounds the brain
- Hagfish have rudimentary eyes - some can sense light, but nothing more
- They are scaleless, which gives their skin a smooth, leathery quality - hagfish skins are sometimes sold as "eel-skin leather"
- They tie themselves in knots to clean off slime, and as a way of leveraging food off carcasses
- Hagfish share a common ancestor with all the vertebrate lineage, including humans
"We know very little about hagfish reproduction, and no-one has ever gotten hagfish to breed in captivity - amazing as that sounds," says Douglas Fudge, who heads the Guelph research project.
"Right now, we literally couldn't have hagfish farms the way we have cows or chickens, or any other domesticated animals in captivity."
Instead, scientists hope to make proteins like the ones found in hagfish slime artificially in the lab.
It's a model that scientists have tried with spider silk before, but because the proteins in spider silk are so large, it takes some pretty wacky-sounding techniques to replicate them (like getting it from the milk of transgenic goats).
Hagfish slime has many similar qualities to spider silk, but has one big advantage, says Fudge - the proteins that make it up are far smaller, and so easier - in theory - to replicate.
No-one has made a spool of hagfish thread yet, but scientists are working on it.
"I'm just taking my tweezers, and then kind of drawing it up," explains post-doc Atsuko Negishi, as she pulls on what looks like the skin on a cup of hot cocoa.
It's actually a thin film of hagfish proteins. This skin collapses, forming a short fibre. She twirls it between her fingers.
"It's kind of like a little piece of hair," she says.
Other members of the team are trying to make threads using genetically engineered bacteria, bypassing the hagfish entirely.
… And some hagfish mysteries
Scientists have been studying hagfish for centuries - Darwin even took notes on them. But there are many basic facts they still don't know. We are still in the dark on how they reproduce and how to tell how old a hagfish is. Bony fish usually have otoliths, which act like tree rings, and are used as a way of telling how old they are - but hagfish don't have these.
If they succeed in perfecting their thread, scientists hope to work closely with the textile industry to bring some products to market.
There might need to be a little re-branding first though.
"Hagfish - it would probably scare people off a little bit!" laughs Tim Winegard.
"I think the name might be a bit of a deterrent," he says. Not to mention the word "slime".
But one day this ancient slime from the depths of the ocean could be woven into the very shirt on your back.