Hagfish, hagfish, hagfish!

by Greg Mayer

I’m teaching vertebrate zoology this semester, and one of my favorite topics in the course is the hagfish. Hagfish are jawless, eel-like fish, whose closest relatives are lampreys. (They were once though to be more primitive than lampreys, but molecular data show the two to form a holophyletic group.)  I was thus quite pleased to find that Vincent Zintzen from the Museum of New Zealand and colleagues have a recent paper in Scientific Reports on hagfish defensive and predatory behavior, with accompanying videos.  There’s more at the website of Te Papa Tongarewa (which is the name of the museum in Maori).

Hagfish are well known for producing copious amounts of viscous slime to discourage predators. In the following video, what’s most remarkable to me is how rapidly the hagfish produces sufficient slime to almost instantaneously deter the predators.

Here’s a closeup of slime production from the Vancouver Aquarium:

And here’s a hagfish preying on a burrowing fish. Zintzen et al. suspect the fish has been killed or disabled by choking with slime while in the burrow.

Hagfish are usually thought of as scavengers (notice the cages of dead meat used as bait in the video).  Here’s a more usual feeding episode: large numbers of hagfish gathering on a whale carcass. That sounds like David Attenborough doing the narration.

Finally, here’s an abridged, combined version of the Te Papa videos (if you want to get the under 4 minute version of the whole story):

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Zintzen V., Roberts, C.D., Anderson M.J., Stewart A.L., Struthers C.D. & Harvey E.S. 2011. Hagfish predatory behaviour and slime defence mechanism. Scientific Reports 1: 131, 6 pp. pdf (Scientific Reports is put out online-only by Nature Publishing Group; papers are given at least some peer review, but are not evaluated for how important or interesting they are.)

31 Comments

  1. Posted November 21, 2011 at 10:49 pm | Permalink

    My wife’s favourite soft leather handbag was made from hagfish skin. Thin, luxuriously soft & pliant, yet tough as old boots. (The hand-bag, not the missus!)
    I think that they are amongst my favourite animals, although I admit that they do not have the appeal of pandas.

  2. Marella
    Posted November 21, 2011 at 11:17 pm | Permalink

    That slime is amazing, it must taste bad surely, to have such a swift and profound effect.

    • Torbjorn Larsson, OM
      Posted November 22, 2011 at 2:54 am | Permalink

      Perhaps. It looks rather pure in the aquarium demo though, so I am guessing it is a rather simple gelatinous compound even before it adsorbs all that water.

      And maybe it doesn’t have to taste anything, if it triggers a choke reflex as it reaches the gills.

      For one, it would be something fishes could have developed to avoid suffocating in mud. (I am speculating here; but we have something similar to avoid lung blockage.)

      For another, it would be along the choking use of that hunt video. If it works, it would be more robust and generic, no pesky predators specializing in ignoring the bad taste compounds. (Still speculating…)

    • Torbjorn Larsson, OM
      Posted November 22, 2011 at 3:04 am | Permalink

      I didn’t learn much on slime, but the usual suspect has it down to that “it has been proposed that the primary protective effect of the slime is related to impairment of the function of a predator fish’s gills.”

      • whyevolutionistrue
        Posted November 22, 2011 at 11:28 am | Permalink

        The Wikipedia article on hagfish is not very good.

        GCM

    • ChasCPeterson
      Posted November 22, 2011 at 6:35 am | Permalink

      It’s mucus, and has no particular taste. Yes, I’ve tasted it.

      • whyevolutionistrue
        Posted November 22, 2011 at 1:02 pm | Permalink

        Wonderful experiment! Have you published on it?

        GCM

  3. Torbjorn Larsson, OM
    Posted November 22, 2011 at 2:43 am | Permalink

    I would never have guessed that the slime was used in such reactive and active ways!

    • Torbjorn Larsson, OM
      Posted November 22, 2011 at 2:59 am | Permalink

      I forgot:

      I noted something odd to me. Some of those predators were pretty large, indicating age. But those unlucky encounters seem pretty memorable.

      Is it a selection effect on the video encounters, assuming hagfish aren’t all that rare? I.e. do most fish simply ignore them because they learn that it is unproductive to attack them, and we are seeing a few individuals that haven’t tried before?

      • Dominic
        Posted November 22, 2011 at 3:09 am | Permalink

        Get you diving gear & a research grant Torbjorn!

  4. Dominic
    Posted November 22, 2011 at 3:08 am | Permalink

    I saw this a few weeks back. What amazes me is the speed of the slime. Do we know the chemical composition of it?

    • Thanny
      Posted November 22, 2011 at 10:42 am | Permalink

      It’s not really as fast as it seems. The vast majority of the slime comes directly from the surrounding seawater. The hagfish basically secretes a small quantity of protein which traps a much larger quantity of water.

      The coolest thing, in my opinion, is that it literally ties itself into a knot, and uses it to clean the slime off itself (so it doesn’t suffocate along with the thing that tried to eat it).

      • Dominic
        Posted November 25, 2011 at 7:10 am | Permalink

        Ta!

  5. Posted November 22, 2011 at 6:11 am | Permalink

    HERE’S a lot of interesting information about Hagfish slime including a short video where a glass of water is turned totally into a blob of slime by the addition of a small amount of the active ingredient. Fun to watch from a distance (like a lot of nature!)

    Hagfish Slime is the new Spiderweb Silk:

    The slime is composed of fine protein slime threads as well as a mucus component that comes packaged in tiny vesicles. When these components are ejected from the slime glands, they combine synergistically to form a slime mass in which a large volume of water is entrained. Recent work by Julia Herr has investigated the chemical composotion of the slime and the mechanisms of mucin vesicle stabilization an deployment. Tim Winegard recently published a paper on the mechanisms of thread skein deployment, which involves the unravelling of 15 cm long threads from subcellular structures…

    These “slime threads” are similar to spider silk in their dimensions, but they differ in a couple of important ways that make them excellent candidates for such a biomimetic project. Slime threads are built within cells from intermediate filament proteins via a process of hierarchical self-assembly. This is quite different from the dynamic spinning process that transforms liquid crystalline spider silk proteins in the silk gland into an insoluble fibre

    The go-to-guy on hagfish slime is Dr. Doug Fudge go look at the Fudge Lab ~ lots of resources for slime fans

    • ChasCPeterson
      Posted November 22, 2011 at 6:37 am | Permalink

      the unravelling of 15 cm long threads from subcellular structures

      wow–I hadn’t known that.

    • Posted November 22, 2011 at 7:01 am | Permalink

      The Hagfish Sliming Video I mention above [1 minute]

    • whyevolutionistrue
      Posted November 22, 2011 at 8:42 am | Permalink

      Great links– thanks Michael!

      GCM

    • Dominic
      Posted November 22, 2011 at 10:30 am | Permalink

      Fudge!

      Thanks.

  6. mday
    Posted November 22, 2011 at 6:41 am | Permalink

    I love that in the second video they have a jar labelled “hagfish slime”.

  7. ChasCPeterson
    Posted November 22, 2011 at 6:49 am | Permalink

    They were once though to be more primitive than lampreys, but molecular data show the two to form a holophyletic group.

    hmmm…Wish I had known about that paper before a recent argument on the subject.
    All of their evidence for cyclostome monophyly is from miRNA. I don’t know enough about miRNA evolution (does anybody, yet?) to accept this single paper as definitive. The chief piece of evidence (granted not the only) seems to be 4 miRNAs that are shared by hagfish and lampreys but not found in gnathostomes, but miRNAs seem to be very commonly lost.
    THe story was much better the old way!

    • whyevolutionistrue
      Posted November 22, 2011 at 1:03 pm | Permalink

      See my new post on hagfish for a bit more on this.

      GCM

  8. AdamK
    Posted November 22, 2011 at 7:39 am | Permalink

    I do not like slime.

    • Dominic
      Posted November 22, 2011 at 10:31 am | Permalink

      Then avoid burial at sea.

      • Dominic
        Posted November 22, 2011 at 10:32 am | Permalink

        See Steve at 12. below…

  9. Gary
    Posted November 22, 2011 at 7:54 am | Permalink

    The common laboratory frog Xenopus leavis (South African Clawed Frog)does something very similar when you handle it, but not with that volume.

  10. VikingWarriorPrinces
    Posted November 22, 2011 at 8:09 am | Permalink

    You get copious amounts of slime from a Hagfish, and the slime sticks to everything. Made dissecting Hagfishes an interesting affair, wrestling with a wet soap describes it pretty well.
    And then we had to clean the lab….

    • Dominic
      Posted November 22, 2011 at 10:31 am | Permalink

      Send Greg the pictures!

      • VikingWarriorPrinces
        Posted November 22, 2011 at 1:43 pm | Permalink

        If I can find them in the blackhole that is known as my study I might do that.
        If you have the Hagfishes in a bucket the water in the bucket will very quickly turn into something akin to jello. It was amazing.

  11. Posted November 22, 2011 at 8:31 am | Permalink

    From a fundamentalist point of view: How lovely and intelligent of God to have the foresight to create slime.

  12. Steve Smith
    Posted November 22, 2011 at 10:01 am | Permalink

    I’ve visited during feeding time at the Vancouver Aquarium’s hagfish tank. After the hagfish ripped through the rotting corpse of their meal and one stuck its mouth out from inside the corpse’s anus, the guide dryly remarked, “Sort of takes the romance out of being buried at sea.”

    I bet they still use that line.

    • Dominic
      Posted November 22, 2011 at 10:32 am | Permalink

      Heard that one before!


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