I want to have my aliens have a culture that clashes with human modern culture and one way I want to achieve this is having some extreme sexual dimorphism.

For these aliens the sexual dimorphism is such that the males are the hosts and the females are the parasites. It's alot like reverse angler fish dimorphism and this is how it works: the females are basically really small tubes with arms and attach themselves to the males' gonads; when the female does it also her immune system and everything else combines with the male's body and they become one. The females know only one thing and that is to attach to the best male and reproduce as fast as possible.

The females outnumber the males 100 to 1. There are three gonads on the male and once they are all taken the females just attach to the previous female forming long chains that look like tails.

As for gestation and birth well gestation occurs in the male once the female has been fertilized and sends the eggs to an organ to store them and then after a 80 day period the one male has a live birth and is sent through a canal through the chain of females and then after that one hundred females are born in tiny eggs. And yes the next up in line females can fertilized when a canal grows up through all of them and send the fertilization material and retrieves and births the eggs. The fertilization and birth cycles only happen once a decade as well

My question is: what kind of environment would this system work best in and what are the benefits to it?

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    $\begingroup$ Angler fish dimorphism works because producing sperms is less energy consuming than producing eggs. In fact males produce billions of sperms while female produce few eggs at once. $\endgroup$
    – L.Dutch
    Feb 12, 2018 at 5:32
  • $\begingroup$ @L.Dutch but all the energy is coming from the make so wouldn't this be basically the same? $\endgroup$
    – Amoeba
    Feb 12, 2018 at 6:00
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    $\begingroup$ Couple of questions: 1: How do gestation and birth work? 2: Do the second/third/etc females in the 'chain' also have a chance of being fertilised? $\endgroup$
    – Joe Bloggs
    Feb 12, 2018 at 6:57
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    $\begingroup$ After your last comments it sounds more like you are swapping names.. the male is acting female and the female is acting male... $\endgroup$
    – L.Dutch
    Feb 12, 2018 at 7:27
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    $\begingroup$ Please edit your question to incorporate any clarification you made in the comments. Comments can theoretically be deleted at any time and people shouldn't need to search for the rest of the question in the comments. $\endgroup$
    – Secespitus
    Feb 12, 2018 at 10:22

1 Answer 1


The reason the angler fish do it is that it is so hard to find each other in the abyss. It is lonely. But if your mate is attached to you it is easy to find her / him.

I agree the proposed switch sort of turns conventional sexes on it head. But in a way the angler fish do what they do as a workaround: they have sensory organs which evolved in the light and under different circumstances. In the dark they need to make it work somehow.

So too your aliens. Your males were huge compared to their females because their very remote ancestors did battle with each other, like elephant seals. Now that hugeness (and perhaps a different mode of feeding / getting resources that helps them get huge) comes in handy, because the parasitic female can take advantage of it.

You could put these things in the deep dark like the anglerfish. Or maybe they are loose in some sort of gaseous void like a gas giant? Or live in interminable labyrinths. A problem is that this sort of individual isolation is in opposition to sociality and if these aliens are going to butt heads with humans they need to be social and cooperative.

Another option: in the remote past the males protected their females from being impregnated by other males and protected the females from predators. It is easier to protect the females (and easier for the females to be protected) the closer they stayed. What you have now is the logical end to that process: maximum closeness.

  • $\begingroup$ Thank you this helps alot, would this maximum closeness make even more sense if every ten years they had one big mating ritual similar to the antechinus but without all the death? $\endgroup$
    – Amoeba
    Feb 12, 2018 at 20:49
  • $\begingroup$ Also one more question if u don't mind answering, how do you think humanity would react to these aliens mating on an individual and group level, not every individual just the layman by today's standereds, I was thinking disgust and accusing the aliens if being barbarians and sexist, what do u think? $\endgroup$
    – Amoeba
    Feb 12, 2018 at 21:15
  • $\begingroup$ The reason to have a mating ritual is if there is some sort of choice involved so you can pick your favorite. If the mates are permanently attached there is no more choice involved and no need for gathering or ritual. Probably you could not even tell they were mating when they were; they are already stuck together. Re disgust: would humans even be able to tell they were looking at multiple individuals when they saw one of these aliens? $\endgroup$
    – Willk
    Feb 12, 2018 at 22:04
  • $\begingroup$ once they establish communication the humans would probably learn if it $\endgroup$
    – Amoeba
    Feb 12, 2018 at 22:12
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    $\begingroup$ @user45751 the females aren't sentient according to your OP, if humans want to whine and cry about it, the aliens can legitimately be confused and ask how they're suppose to change the very base of their reproductive system set up by evolution. $\endgroup$
    – Dan Clarke
    Feb 13, 2018 at 4:15

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