Scientists make tank out of gelatine to see secrets of hagfish "homes"

Hagfish are strange, somewhat scary creatures with a skull and no spine. Scientists have done something quite unique to peer into the "home" burrows of hagfish in seafloor sediments, by creating a transparent tank made out of gelatine.

Hagfish comprise multiple species. Credit: Peter Southwood.
Hagfish comprise multiple species. Credit: Peter Southwood.

Hagfish are eel-like jawless fish also known as slime eels. They the only known animals living today that have a skull but no spine (vertebral column), despite having some basic vertebrae.

But where does the slime eels name come from? In the sea they are predators and scavengers, defending against other predators by releasing slime through mucous glands in their skin. This expands to about 10,000 times its size in the water, all within two fifths of a second.

They are descendants of hagfish from about 310 million years ago, during the Late Carboniferous, more closely resembling ancestors from the mid-Cretaceous – which is more recent at about 100 million years ago.

youtube video id=F8aVgSIDJjM

They are usually about 50 cm long. The largest species of their kind is named Eptatretus goliath spanning a length up to 127 cm.

Observing hagfish homes: How do they burrow?

Scientists recently “dug into” the mysteries of how hagfish burrow. The team at the Schmid College of Science and Technology at Chapman University created a new way to observe their secrets.

Normally, sediment in the natural environment would obscure the view of what hagfish are doing in seafloor sediments, where they make burrows and navigate within them.

Dr. Douglas S Fudge and his team made a tank out of transparent gelatine, and then watched how the hagfish moved in sediment. This helps to understand not only hagfishes, or the structure of their burrows, but how sediment is mixed in these marine benthic habitats, which influences their chemistry.

“For a long time we’ve known that hagfishes can burrow into soft sediments, but we had no idea how they do it. By figuring out how to get hagfish to voluntarily burrow into transparent gelatine, we were able to get the first ever look at this process.”

They found that hagfish curiously make a U-shaped burrow by thrashing then vigorously swimming, followed by side-to-side head shifts, then a wiggle phase. This may sound chaotic but this sequence seems to be a powerful burrowing strategy. A similar movement can be seen in types of burrowing snakes and even amphibians.

Their locomotion could even inspire the design of burrowing robots, through biomimicry – creating designs or innovations that mimic how aspects of nature looks or works.

Source of the news:

The team’s observations are shared in their published research publication titled “Biphasic burrowing in Atlantic hagfish” in The Journal of Experimental Biology.