For the opening of the permanent gallery in Ottawa the education staff is planning to have a live animal demonstration. These are always popular and are a great way to make lasting connections for our visitors. One possibility for this demo is a very cool little animal that very few people know about – the hagfish. I recently had the chance to visit Dr. Douglas Fudge at the University of Guelph. Dr. Fudge’s team studies the hagfish and their particular predator evasion technique. Before I explain further, I want to introduce you to the hagfish. Hagfish are eel-like scavengers that live on the bottom of the ocean and feed on dead fish and whales that fall to the ocean floor. They belong to a group called the Agnatha, or jawless fish, along with lampreys. Having no jaw, they have evolved interesting ways of getting the flesh off the carcasses on which they feed.
Dr. Claude Renaud of the Canadian Museum of Nature explains.
The knotting behavior of hagfishes is truly fascinating. It probably evolved to facilitate their feeding. While these animals possess several rows of teeth, they do not possess any jaws; so how do they remove chunks of flesh from dead fishes? After they firmly sink their numerous teeth into the soft flesh of decaying fish, they loop their bodies into a simple knot close to their head region and slip it back progressively towards their tail permitting the tearing of the flesh as if they had true biting jaws.
That’s right. These long slippery eel-like fish can actually tie their bodies into a knot. The knots may also be useful in another sense. When a hagfish is harassed by a predator they produce this incredible slime that clogs the predator’s gills. All of this happens in less than a second. Knotting their bodies can help them wipe the slime off themselves and prevent their own gills from getting clogged.
Now, producing slime in large quantities that quickly is cool enough on its own, but the slime itself is even more amazing than that. While I was visiting the lab, Dr. Fudge showed me how the hagfish “slime”. Then we fished out the slime so that I could feel it. It was not the goo I expected but rather it is mostly seawater that is bound by a spiderweb like substance. As the slime released its water, it began to feel more and more fibrous. Eventually it felt like wet spiderweb and had lost most of its volume. It was a very memorable experience and one that I won’t forget for a long time!