The world’s slimiest animal - Noah R. Bressman and Douglas Fudge
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Hagfish are a group of primitive, eyeless, jawless, boneless, stomachless fish that have changed very little over hundreds of millions of years. However, because they do not have bones or many hard parts, they don’t preserve well in the fossil record, so we know very little about their ancestors. We do know that they were not always able to produce slime, though. How do we know this? Only two hagfish fossils have ever been discovered, one from about 330 million years ago and one from about 130 millions years ago. Because the younger fossil showed evidence of slime glands but the older fossil did not, scientists estimate the hagfish evolved their defensive slime sometime in this interval.
For more information about hagfish fossils and their evolution, check out this article!
How many hagfish are there?
In terms of the number of individuals, it is hard to say because they live very deep down in the ocean in areas where it is difficult to study them. This is problematic because hagfish are harvested from around the world for food and to make leather from their skin, but we do not know how many hagfish are in the oceans, so we cannot determine a sustainable quota for hagfish harvest. Unfortunately, we have seen declines in many hagfish populations, leading some species to be endangered or threatened with extinction. Therefore, it is imperative to learn more about hagfish in the wild to best protect their populations as well as make new discoveries.
In 2021, four new hagfish species were discovered on a single expedition to the Galapagos Islands, bringing the total number of known hagfish species up to 87. Because of their lack of jaws, deep depths, and ability to escape tight spaces, hagfish are not easy to catch or find unless you have custom-built hagfish traps or access to baited remote underwater videography (BRUV), so many species have gone undescribed until recently. Even still, there are likely many more hagfish species out there waiting to be described from the deepest, darkest depths of the oceans.
To learn more about the recent discovery of new hagfish species in the Galapagos, check out the manuscript of the research!
What does hagfish slime feel like?
Most biological slimes and mucus are very similar; they are slippery, goopy, and viscous, but can be separated into pieces easily – try this the next time you sneeze into your hands. While hagfish slime is slippery and goopy, it also is pretty tough and resilient. The protein thread network in hagfish slime reinforces the mucus, making it a bit springy and stretchy. Because of this, it can be pretty tough to tear a chunk of hagfish slime into separate pieces. However, most of the water in hagfish slime is loosely bound. If you wring out a handful of hagfish slime like a sponge and play around with it, it will lose most of its water, leaving you with a tiny amount of clumped threads.
For more information on hagfish slime, check out Dr. Doug Fudge’s Website!
Why try to build something from scratch if somebody else already built something similar? That is the principle behind biomimetics, a scientific field inspired by the materials of nature. Biomimetics aims at understanding the remarkable materials made by animals, plants, and microbes in the hopes of recreating them with our technology to solve human engineering problems or build things better. Studying hagfish slime threads to learn how to create tough fibers is but one of many examples of biomimetics. Wings of aircrafts are often modeled after birds, high-strength suction cups are modeled after fish suction cups and gecko feet, and more effective wind turbine blades are modeled after humpback whale flippers. Because nature is endless, biomimetics is filled with endless possibilities.
For more information on biomaterials, check out these materials from TED-Ed!
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