The bizarre anglerfish: first video of their equally bizarre mating

You’ve surely heard of the bizarre anglerfish. There are actually many such species in the order Lophiiformes, but the most famous are the deep-sea species with fearsome teeth who attract their prey with a luminescent lure. (All anglerfish are carnivorous.) Here’s a picture of ten such species from Wikipedia:

Their huge mouths and distendable stomachs enable them to eat prey twice their size: a useful adaptation in the deep sea, where prey are few and far between. And the reproduction of some species, as shown in the stunning video below, is totally bizarre (see this Mental Floss piece for more information). Males are tiny, and weren’t even known to exist until many females had been caught, many afflicted with “parasites”. Scientists eventually realized that the parasites were actually males whose bodies had become permanently fused to the female. That’s a good mating strategy because finding a female in such sparse populations is a real problem. But it’s almost unique in animals.

When males are born, they have to find a female, and they do so by homing onto her using both her light and species-specific pheromones. Such males can’t feed, and don’t get mature gonads until they attach to a female. When a male does that, he secretes an enzyme that dissolves his head and the female’s body wall, allowing the pair to fuse right down to joining their blood vessels. The male remains attached to the female for life, and can spawn repeatedly until she dies (how the male releases sperm when the female produces eggs is something I haven’t yet found out). As I used to tell my students, to their great delight, “the male anglerfish is simply a parasitic sack of gonads—much like undergraduate men.”

A piece in Science by Katie Langin describes the filming of the first pair of mating anglerfish, made at 800 meters near the Azores by Kirsten and Joachim Jakobsen in a submersible (shown in the video below). They followed the 16-cm animal (about six inches long: the size of an American dollar bill) for 25 minutes, and later identified the species as Caulophryne jordani, or the “fanfin angler”, which has a worldwide distribution.

The short video below, put out by the AAAS, shows several interesting features:

  • The long whiskers of the females of this species, which likely act as feelers. These structures appear to glow like the bioluminiscent “lure,” but the researchers aren’t sure whether the glow of the whiskers is intrinsic or merely reflections from the submersible.
  • The male seems to move his body about independent of the female
  • The female uses little energy swimming, and appears to mostly drift around. That’s probably an energy-saving adaptation in a food-poor environment. After all, why swim when you have nowhere to go, and when your prey comes to you?

Have a gander of one of the world’s truly bizarre creatures, and one of the marvels of natural selection.

h/t: Matthew Cobb


  1. yazikus
    Posted March 22, 2018 at 11:32 am | Permalink


    • rickflick
      Posted March 22, 2018 at 4:58 pm | Permalink

      You took the word right out of my jaws.

  2. ThyroidPlanet
    Posted March 22, 2018 at 11:36 am | Permalink

    I think I heard of the male shriveling up in …. cant recall … it was only a few years ago too, making me wonder “how did I miss that?!”

    • Posted March 22, 2018 at 11:42 am | Permalink

      I think I read that it was absorbed into her body!

      • loren russell
        Posted March 22, 2018 at 1:55 pm | Permalink

        This male seems pretty much intact, with visible head structures {?even eyes?]. Perhaps they are just dating?

        • Posted March 22, 2018 at 4:07 pm | Permalink

          He’s just not quite ready yet to make a commitment.

  3. BJ
    Posted March 22, 2018 at 11:37 am | Permalink

    The anglerfish is one of my favorite animals of the group I like to call The Fucking Bonkers Banana Club. Now I get to see how they mate! And, quelle surprise, the mating mechanism is also befitting of their status in the FBBC.

    Congratulations, anglerfish. You have lived up to the legend of your stature as a FBBC member.

    • yazikus
      Posted March 22, 2018 at 12:03 pm | Permalink

      You could totally have a nature-channel show of this. Kiddo likes those ’72 Dangerous Animals of Blabla’ shows- and they do a sort of contest to see which one is the baddest of the bad.

      • BJ
        Posted March 22, 2018 at 3:53 pm | Permalink

        My nephew loves watching Youtube videos about the ten biggest predators, or the ten craziest animals, or the ten animals you won’t believe exist/existed, etc. He’s really into megaladons right now.

        • gravelinspector-Aidan
          Posted March 23, 2018 at 12:58 pm | Permalink

          He’s really into megaladons right now.

          He’ll be able to get into a Megalodon (did they still exist) until pretty much full-grown adulthood, without troubling it’s teeth.

    • Jenny Haniver
      Posted March 22, 2018 at 4:56 pm | Permalink

      The angler fish have some cousins that also definitely belong in your FBB Club. How about the handfish;? Check out these weird beauties that walk around on their hands (and feet), and the “arms” and hands do seem quite limb-like, even when they’re lounging around (sort of like the way I might lie around on the floor)- as can be seen in this short video at around .58

      Another relative is the frogfish They also have hands.

      • BJ
        Posted March 23, 2018 at 9:56 am | Permalink

        Thanks. I had never heard of these other Fish Fuck-ups.

        Now I have to order three more custom plaques to hang in my dedicated clubhouse. I wonder why nobody visits…

  4. glen1davidson
    Posted March 22, 2018 at 11:38 am | Permalink

    That’s a committed pair!

    Glen Davidson

  5. Posted March 22, 2018 at 11:45 am | Permalink

    Am I right in thinking more than one male can be attached to the female?

    • gravelinspector-Aidan
      Posted March 23, 2018 at 1:02 pm | Permalink

      I was wondering precisely that.
      In order to share blood streams, there probably has to be some interesting immunology going on there. Hijacking that to “repel boarders” would probably have a significant reproductive benefit – to the male. For the female, not so clear.
      I bet – since I’ve not heard of any work on such questions- that keeping them alive in the lab is an absolute piglet of a problem.

  6. Randall Schenck
    Posted March 22, 2018 at 11:47 am | Permalink

    I can hear that famous old line – g*d works in mysterious ways.

    • Heather Hastie
      Posted March 22, 2018 at 12:49 pm | Permalink

      I think this one is a good question for God. What is the point of its existence? Why, exactly, did you create it? Had you been on the wacky baccy and wanted to out-weird the platypus?

      Otoh, you can see how such a creature could have evolved, and it’s so cool!

      • Posted March 22, 2018 at 7:54 pm | Permalink

        Always figured that god thought we’d never get smart enough to look that far down deep, so he never bothered to finish them.

        • Heather Hastie
          Posted March 22, 2018 at 8:13 pm | Permalink

          Ha ha! Good call. That pesky free will. 😀

      • Posted March 22, 2018 at 9:29 pm | Permalink

        God was on drugs.

        • Posted March 22, 2018 at 9:55 pm | Permalink

          Bad LSD trip?

          • gravelinspector-Aidan
            Posted March 23, 2018 at 1:03 pm | Permalink

            Pscilocybin, I’d call.

        • Heather Hastie
          Posted March 22, 2018 at 11:33 pm | Permalink

          It’s the only explanation. Or excuse …

    • Posted March 22, 2018 at 1:24 pm | Permalink

      Clearly, these heathen fishes are all that remain of the Fallen. They are forever doomed to float in a cold abyss far from the Light. Meanwhile, the Chosen ones fly in the sky on white feathered wings while eating seafood delicacies from the waters surface. Why, you might hear them squawking their praises toward Heaven even now!

      • Randall Schenck
        Posted March 22, 2018 at 3:31 pm | Permalink

        I agree with all of these comments. The mysterious excuse just won’t cut it. How did you create this? A perfect evolutionary example that trashes intelligent design or a divine creator in every way.

  7. W.T. Effingham
    Posted March 22, 2018 at 11:47 am | Permalink

    Love that last phrase in the video (angler fish mysteries for some time to come). It sounds like a great incentive for budding marine biologists.

    • neil
      Posted March 22, 2018 at 1:33 pm | Permalink

      Budding? So marine biologists reproduce asexually?

  8. GBJames
    Posted March 22, 2018 at 12:16 pm | Permalink

    Does the term “parasitic” actually apply here? Isn’t this more like “mutualism”? But even that seems wrong since these aren’t individuals of different species. It is just weird mating strategy.

  9. Posted March 22, 2018 at 12:28 pm | Permalink

    Yes, amazing. But after learning about this fish is off the lunch menu for today.

  10. Simon Hayward
    Posted March 22, 2018 at 12:28 pm | Permalink

    Does anyone know enough about fish immunology to tell us how the male does not get rejected as non-self? I never figured this out or knew who to ask.

  11. drew
    Posted March 22, 2018 at 12:35 pm | Permalink

    Anglerfish porn! There should be an NSFW warning on this video! 😀

  12. JonLynnHarvey
    Posted March 22, 2018 at 12:44 pm | Permalink

    Well, if I want to be really really un-PC, the next time someone tells me they feel like a man trapped in a woman’s body, I can say
    “Do you mean like Billy Tipton, or like an anglefish?”

  13. Mark R.
    Posted March 22, 2018 at 12:52 pm | Permalink

    Amazing footage: the quality and sharpness is stunning. Dream job: operating one of these submersibles and filming denizens of the deep.

  14. Christopher
    Posted March 22, 2018 at 12:58 pm | Permalink

    There are more than a few human males who are little more than a parasitic pair of testicles. 😬

    • Posted March 23, 2018 at 12:06 pm | Permalink

      I think some of them have the other part of that organ, to be fair.

  15. Ken Kukec
    Posted March 22, 2018 at 1:09 pm | Permalink

    Mama always told me, when you find a good woman, never let go. (Then again, Mama was given to singing “Some Enchanted Evening” while workin’ ’round the house, so maybe I’m just recalling those lyrics.)

  16. Posted March 22, 2018 at 1:16 pm | Permalink

    Wonderfully weird, and that makes it even more wonderful.
    On a greater scale of this sort of thing, we large multicellular species sit atop the narrow part of an energy pyramid where the carrying capacity is limited. Meanwhile, ‘below’ us on the broader part of the pyramid there are the far more numerous microbes where resources are available to support far more individuals. We are like these resource scarce angler fishes without knowing it.

  17. Melanie
    Posted March 22, 2018 at 3:13 pm | Permalink

    Wow! Incredible. I had no idea.

  18. Curt Nelson
    Posted March 22, 2018 at 3:28 pm | Permalink

    I think it’s weird that these deep-living fish look so unathletic, like they were designed by a cartoonist. Maybe they just move very little — they lure their food in.

  19. Diane G.
    Posted March 22, 2018 at 3:55 pm | Permalink

    Wonderful footage of live anglerfish! First time I’ve ever seen those filaments which are such a prominent part of the live female.

    I got to wondering how anglerfish spawn develop and survive till they’re big enough to be deep-sea predators like their mom. Turns out at least one species (and probably many more–I just got tired of searching) follows a typical ocean fish strategy of hatching out tiny larvae that swim to the surface and eat plankton. The spawn itself is interestingly arrayed–perhaps this “sheet” makes it easier for more eggs/larvae to drift near enough to the surface to survive:

    “The female will lay her eggs in a thin sheet of gelatinous material two or three feet (about one meter) wide and about 30 feet (9 meters) long. This thin sheet of eggs floats free in the sea until the eggs hatch into tiny larvae. Once hatched, the larvae swim to the surface and feed on plankton. As they mature, they return to the depths below.”

  20. Posted March 22, 2018 at 4:19 pm | Permalink

    Reblogged this on The Logical Place.

  21. Jenny Haniver
    Posted March 22, 2018 at 4:20 pm | Permalink

    The article in Science is excellent. A must-read.

  22. Posted March 23, 2018 at 7:07 am | Permalink

    “You’ve surely heard of the bizarre anglerfish.”

    I’m not sure if I have or not.

    I’m trying to figure out if “bizarre anglerfish” is the name of a specific type of anglerfish separate from not-so-bizarre anglerfish, in which case, no, I haven’t heard of them.

    But if all anglerfish are considered bizarre then yes, I’ve heard of anglerfish.

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