National Geographic

Indiscriminate squid just implanting everyone with sperm


In the dark abyss of the ocean, animals cannot afford to be choosy. The odds of bumping into another individual are low, and appropriate willing mates are even harder to come by. To deal with this problem, the deep-sea squid Octopoteuthis deletron has become somewhat indiscriminate. The males will mate with any squid they come across, whether they’re male or female.

Hendrik  Hoving from the Montery Bay Aquarium Research Institute found evidence of these same-sex matings with a robot submarine. Controlled from a surface ship, these vehicles can explore depths that humans cannot. The subs have captured videos of O.deletron since 1992 (videos here), but the team have only just revealed the nature of the squid’s sex life by studying the archival footage.

O.deletron is a handsome red squid, around five inches long, with hook-lined arms and flashing patches on its flanks and arm tips. Most squid and octopuses deliver their sperm along one of their arms – a modified limb called a hectocotylus. O.deletron is unusual in having a separate penis, distinct from its arms. It uses this long organ to dab a female’s body, attaching a pouch called a spermatophore, which contains millions of sperm. The pouch discharges sacs called spermatangia, which implant themselves in the female’s body. The sacs are visible from the outside, marking out recently mated individuals for observant scientists to see.

Hoving found these sacs on the bodies of both male and female squid in equal proportions. Both sexes had been implanted with sperm.

This is just one of thousands of examples of homosexual behaviour in animals, and there have already been a few reports among cephalopods – the group that includes octopuses, squids and cuttlefish. The famous giant squid might even partake in gay sex from time to time. Of the twelve mature males that have been found, seven had spermatangia implanted on their arms.

However, Hoving notes that some of these squid were caught in nets, and in their distress, they may have mistakenly implanted themselves with their own sperm. He also says, “Accidental self-implantation during mating with a female is also a possibility.” But that’s not the case for O.deletron. Hoving noticed sperm sacs on parts of the males’ bodies that lie beyond the reach of their penises. They must have been stuck there by another male.

But why would O.deletron males waste their sperm on other males? Hoving thinks that speed is the answer. Many species of squid live fast and die young. They only have a narrow window in which to have sex before they perish, so they do so very quickly. There is little time for an elaborate courtship when your reproductive life is quickly ticking away.

A male O.deletron that encounters another individual has mere seconds to decide whether to implant its spermataphore or not. That choice isn’t helped by the fact that males and females are roughly the same size with only minor physical differences. If the male chooses poorly, and misses out on a suitable female, it could well die before it stumbles across another mate. Better to ejaculate on everyone, and ask questions later.

Reference: Hoving, Bush & Robson. 2011. A shot in the dark: same-sex sexual behaviour in a deep-sea squid. Biol Letters http://dx.doi.org/10.1098/rsbl.2011.0680

Image copyright of MBARI

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There are 13 Comments. Add Yours.

  1. Klio
    September 20, 2011

    I got as far as “same-sex matings with a robot submarine” and, astonished, went back to reread the sentence.

  2. Thomas
    September 20, 2011

    Wham, bam, thank you… ?

  3. Shade
    September 21, 2011

    I always thought it was octopi not octopusus… It seems my spell checker agrees with me.
    I was worried I had missed something.
    How long do these squid live? Your article stresses that they have short lives but I didn’t see anything regarding how short it is.
    How much of their lives do they spend sexually viable?

  4. Joshua
    September 21, 2011

    The mating strategies that end up being successful down there are always so fascinating. Like the anglerfish males latching themselves to and being almost absorbed by the females.

    @Shane – The wikipedia article for octopus explains it. In short octopuses is acceptable since it conforms to standard English pluralization and already has so much traction. The root is from Greek though so if you want to use that pluralization then the correct form would be octopodes. Octopi comes from the mistaken idea that the root it Latin.

  5. Katharine
    September 21, 2011

    Small correction: the researcher’s name is Henk-Jan Hoving.

  6. Pascale
    September 21, 2011

    “evidence of these same-sex matings with a robot submarine”

    So robot submarines are male?
    Oh, wait. Now I understand…

  7. Ed Yong
    September 21, 2011

    @Pascale – Heh. Could’ve worded that better.

    @Katharine – Yes, I noticed that, but he’s Hendrik J. T. Hoving on the paper, so the J presumably stands for Jan and the Henk is short for Hendrik.

  8. Garrett
    September 22, 2011

    “Better to ejaculate on everyone, and ask questions later.”

    I mean how did we get to 7 comments and no one mention this? Classic… well said!

  9. Shade
    September 22, 2011

    That is very interesting, thanks josh.

  10. John
    September 22, 2011

    It sounds to me like a squid can’t tell whether other squids are male or female so it just slaps a spermatophore on any squid it meets and some just happen to be male. That doesn’t sound like homosexual sex. I’m not even sure they could be considered bisexual in the way the term is used for humans, if the squid doesn’t know what gender its partner is.

    It sounds like more research is needed before one can conclude that this is an example of homosexual behavior.

  11. Stan
    September 23, 2011

    I think the author needs to characterize this creature’s behavior using terms other than “homosexual behaviour” and “gay sex”. In the human animal, these terms denote sexual behaviour which same-sex individuals engage in for mutual pleasure rather than procreation.

    These creatures, and many of the other “thousands of examples of homosexual behaviour in animals” are not for the pleasure of the individuals. They are simply a byproduct of the natural drive to procreate, destined to failure when the sexual behaviour involves a same-sex mating.

  12. Joe
    January 16, 2013

    For some reason, this squid’s reproductive tactics don’t seem to fit into the homosexuality category. Inseminating other males because of a narrow time window and poor gender differentiation is different than being attracted to other males. It’s like saying that species who just scatter their sperm in the currents engage in homosexual activity because their sperm sometimes lands on other males.

  13. Joe
    January 16, 2013

    I see two other people already made the same point. Plus the fact that this squid has attempted to mate with the submarine.

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