
Pom-pom crabs fight over tiny anemones, which they hold like boxing gloves - mhb
https://www.washingtonpost.com/news/morning-mix/wp/2017/02/03/watch-pom-pom-crabs-fight-over-tiny-anemones-which-they-hold-like-boxing-gloves/
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amelius
> The pom-pom crab, the scientists speculated, is perhaps the only animal on
> the planet that controls another species’ growth, feeding and asexual
> reproduction.

Speaking about controlling another species, this story [1] where a wasp
performs brain-surgery on a cockroach also seems pretty interesting.

[1] [https://www.wired.com/2014/02/absurd-creature-of-the-week-
je...](https://www.wired.com/2014/02/absurd-creature-of-the-week-jewel-wasp/)

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darkerside
> the only animal

Besides us, that is.

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ccozan
I designate myself and my other fellows as humans.

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Majestic121
You can designate yourself as you wish, it doesn't make you/us less of an
animal

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amelius
What is the proper word for "animals minus humans"?

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tantalor
[https://en.wikipedia.org/wiki/Non-human](https://en.wikipedia.org/wiki/Non-
human)

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btschaegg
You wrote the first HN comment that made me sad I only can upvote it once.

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jerf
Is it possible that the only remaining population of these particular anemones
is in the claws of these crabs? That the only mechanism they have left for
propagating is precisely the fighting and splitting seen in the tests? That
would be wild. Could be checked by seeing if they're all clones. (Wouldn't
necessarily be proof but it would be evidence.)

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crazydoggers
I'm pretty sure they are fairly prolific outside of the crabs use.

In the reef keeping world you can actually keep Pom Pom crabs in your aquarium
with their anemones. If they lose the anemone for some reason, they often will
find another anemone or even some coral to use.

Here's more info on the anemone they use.

[https://en.m.wikipedia.org/wiki/Triactis](https://en.m.wikipedia.org/wiki/Triactis)

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mfrykman
"The pom-pom crab, the scientists speculated, is perhaps the only animal on
the planet that controls another species’ growth, feeding and asexual
reproduction."

Except for scientists, of course.

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moron4hire
I recall reading something about a species of ants that cultivated aphids for
some fluid they secrete.

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mhb
Yes [1]. And leafcutter ants farm fungus. I think the distinction is the level
of involvement of the crabs in the anemones' reproduction.

[1][https://www.sciencedaily.com/releases/2007/10/071009212548.h...](https://www.sciencedaily.com/releases/2007/10/071009212548.htm)

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moron4hire
This species sounds more like they are in control of the aphids' reproduction,
to the point the aphids have evolved a new organ.

[https://www.sciencedaily.com/releases/2012/07/120702134037.h...](https://www.sciencedaily.com/releases/2012/07/120702134037.htm)

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pasta
Some years ago I had a reef tank. Most people start a reef tank by adding live
rock. Those are rocks straight out of the sea.

It's amazing what live rock realy means. Every cm³ is covered with some form
of live. Worms, crabs, starfish, anemones, you name it.

We know so little about this world. It's a shame we are busy destoying large
areas of the ocean.

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WayneBro
Another interesting crustacean is the Mantis Shrimp - it's got a fast and
powerful punch that reaches 73 feet per second (50 miles per hour) within 3
milliseconds - [https://www.youtube.com/watch?v=DtNAqK_V-
lg](https://www.youtube.com/watch?v=DtNAqK_V-lg)

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stuart78
Those eyes are crazy. I'm jealous of all of the animals that have a greater
range of color perception than us. If I could trade for any trait, it'd be
that.

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JoeAltmaier
My understanding is human lens is a filter - removes ultraviolet. Early
replacements didn't filter, some old folks could see colors the rest of us
don't know about!

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lsaferite
Mantis shrimp can see light polarization as well. They have amazing vision
range.

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evincarofautumn
Humans can, too, though not very well. Stare at a bright white LCD—you should
see orthogonal double-fan shapes, one bluish, one yellowish.

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moron4hire
I personally see it more readily from red LED digits on my alarm clock at
night. IDK if it's generally better conditions or biological difference.

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TD-Linux
LEDs don't produce polarized light. You might be seeing the matrix scanning.

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moron4hire
Don't know why I said LED. Alarm clocks are almost never LED. It's a backlit
LCD.

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sosuke
Better quality and longer video
[https://www.youtube.com/watch?v=vgWy0uOg54A](https://www.youtube.com/watch?v=vgWy0uOg54A)

Boxer crabs induce asexual reproduction of their associated sea anemones by
splitting and intraspecific theft
[https://peerj.com/articles/2954/](https://peerj.com/articles/2954/)

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pvaldes
> “but we’ve never found a free-living anemone,”

(Fifteen secons of google later...)

And here you have your free-living anemone of the same species.

[http://actiniaria.com/img/triactis_producta_1.jpg](http://actiniaria.com/img/triactis_producta_1.jpg)

You're welcome

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zem
that was the most interesting bit of the article for me, so i went to see what
the anemone wikipedia page said and i found

> Triactis producta is found in shallow waters of the tropical Indo-Pacific
> Ocean, its range extending from the Red Sea and Mozambique to Hawaii and
> French Polynesia. It is inconspicuous, often growing in crevices and
> concealed among the branches of stony corals. It often occurs in dense
> clusters of what are probably cloned individuals.

i really wonder how that quote got into the article - was schnytzer somehow
misquoted? was he talking about years ago when the anemones were seen on the
crabs but not yet found in the corals? it seems unlikely that he would simply
be wrong about scientists not having found out where the anemones lived in the
wild.

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Dowwie
This was one hell of a David vs Goliath match

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JoeAltmaier
But... why?!

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crooked-v
For evolution, the answer tends to be "why not?"

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acqq
And also very often: those who don't do it can't get to have successful sex.

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Unbeliever69
Am I the only one that read this as porn-porn crabs?

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anigbrowl
No, but if you're like me it might be time to visit the optician again :)

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busted
Hacker News.

