# Question about amoebas vis-a-vis the evolution of blood-sucking behavior.

**URL:** <https://boards.straightdope.com/t/question-about-amoebas-vis-a-vis-the-evolution-of-blood-sucking-behavior/818127>\
**Category:** Factual Questions\
**Created:** [July 18, 2018, 6:43am UTC](https://boards.straightdope.com/t/question-about-amoebas-vis-a-vis-the-evolution-of-blood-sucking-behavior/818127 "2018-07-18T06:43:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![brujaja](https://avatars.discourse-cdn.com/v4/letter/b/4af34b/32.png) [@brujaja](https://boards.straightdope.com/u/brujaja)\
**Post date:** [July 18, 2018, 6:43am UTC](https://boards.straightdope.com/t/question-about-amoebas-vis-a-vis-the-evolution-of-blood-sucking-behavior/818127/1 "2018-07-18T06:43:06Z")

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A friend and I got to talking about mosquitos tonight, and that made me wonder about how their specialized bloodsucking system evolved.

I said, I wonder if there were single-celled organisms that developed organelles to suck out the contents of other amoebae, rather than engulfing them?

Then I looked it up, and it turns out that blood-sucking evolved several times, and probably not in that way. (I like the plant-sucking theory, personally. It makes sense.)

But I’m still wondering about amoebae, and whether any of them do that?

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**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\
**Post date:** [July 18, 2018, 8:56am UTC](https://boards.straightdope.com/t/question-about-amoebas-vis-a-vis-the-evolution-of-blood-sucking-behavior/818127/2 "2018-07-18T08:56:18Z")

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> [@brujaja](#):
>
> I said, I wonder if there were single-celled organisms that developed organelles to suck out the contents of other amoebae, rather than engulfing them?

Not amoebae, but heterotrophic dinoflagellates use the [_peduncle_](http://www.coastalwiki.org/wiki/Marine_Plankton#Protozoa) to pierce and extract nutrients. There’s also the [suctoria](https://en.wikipedia.org/wiki/Suctoria) cilliates.

Your OP phrasing seems to indicate that you think all, or most, unicellular animals are amoeboid. That is far from the case.

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**Author:** ![brujaja](https://avatars.discourse-cdn.com/v4/letter/b/4af34b/32.png) [@brujaja](https://boards.straightdope.com/u/brujaja)\
**Post date:** [July 18, 2018, 9:41am UTC](https://boards.straightdope.com/t/question-about-amoebas-vis-a-vis-the-evolution-of-blood-sucking-behavior/818127/3 "2018-07-18T09:41:10Z")

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**MrDibble:** Guilty as charged. I debated whether to say “microorganisms,” or stick with “single-celled organisms,” because I was pretty sure there were other kinds besides amoebae, but ultimately my enthusiasm won out over a detour to wiki pages. (btw I like “unicellular” much better, it’s far less clunky than “single-celled.”)

Awesome links!! Dinoflagellates, the original vampires!

Makes sense to develop alternatives to engulfing prey, just in case you want to eat something bigger than your head. 🙂