
A creature that eats its own brain - jelliclesfarm
https://goodheartextremescience.wordpress.com/2010/01/27/meet-the-creature-that-eats-its-own-brain/
======
brudgers
The headline evoked my twisted like a Monty Python youth. Or _the Haggis Poem
aka Horace_

    
    
      Much to his dad and mum's dismay 
      Horace ate himself one day 
      He didn't stop to say his grace 
      He just sat down and ate his face 
      "We can't have this!" his dad declared 
      "If that lad's ate he should be shared" 
      But even as he spoke they saw 
      Horace eating more and more: 
      First his legs and then his thighs, 
      His arms, his nose, his hair, his eyes 
      "Stop him someone!" Mother cried 
      "Those eyeballs would be better fried!" 
      But all too late for they were gone, 
      And he had started on his dong... 
      "Oh foolish child!" the father mourned 
      "You could have deep-fried those with prawns, 
      Some parsely and some tartar sauce..." 
      But H was on his second course; 
      His liver and his lights and lung, 
      His ears, his neck, his chin, his tongue 
      "To think I raised himn from the cot 
      And now he's gone to scoff the lot!" 
      His mother cried what shall we do? 
      What's left won't even make a stew..." 
      And as she wept her son was seen 
      To eat his head his heart his spleen 
      And there he lay, a boy no more 
     Just a stomach on the floor... 
      None the less since it was his 
      They ate it - and that's what haggis is

~~~
jelliclesfarm
thanks for mentioning the haggis poem!it brings to mind another of my
favourites..the reluctant cannnibal by flanders and swann...altho it has an
happier(and tastier) ending...roasted leg of insurance salesman

[https://www.youtube.com/watch?v=dZ6LzqV1ebk](https://www.youtube.com/watch?v=dZ6LzqV1ebk)

------
alejohausner
The juvenile sea squirt wanders through the sea searching for a suitable rock
or hunk of coral to cling to and make its home for life. For this task, it has
a rudimentary nervous system. When it finds its spot and takes root, it
doesn't need its brain anymore, so it eats it! It's rather like getting
tenure.

Daniel Dennett

~~~
JadeNB
A classic, and my first thought when I saw the headline.

------
pmoriarty
_" The sea squirt larvae begin absorbing all the tadpole-like parts that made
them chordates. Where the sea squirt larva once had gills, it develops the
intake and exist siphons that will help it bring water and food into its body.
It absorbs its twitching tail. It absorbs its primitive eye and its spine-like
notocord. Finally, it even absorbs the rudimentary little "brain" (cerebral
ganglion) that it used to swim about and find its attachment place."_

By that measure, I suppose a caterpillar also "eats its own brain" during its
transformation in to a butterfly.

~~~
wyattpeak
It may be overstated for effect (which the author acknowledges), but it's a
little more dramatic than a caterpillar in that it ends up without a brain,
while a butterfly doesn't.

I also don't think current thinking holds that the organs of a caterpillar
disappear completely during metamorphosis, though I could easily be wrong.

~~~
MacsHeadroom
A caterpillar becomes a soup of cells, fats, and proteins. Some species do not
retain any multi-cellular structures- others only a tiny few.

Interestingly, the still exhibit learned avoidance behaviors after complete
this near complete disassembly and reassembly.

~~~
wyattpeak
Are you an expert? If so I defer, but if not I think you're repeating an old
understanding of the process. From a bit more reading a substantial portion
seems to dissolve, but far from everything.

Here's a paper tracking the metamorphosis of painted lady butterflies in
considerable detail:

[https://royalsocietypublishing.org/doi/10.1098/rsif.2013.030...](https://royalsocietypublishing.org/doi/10.1098/rsif.2013.0304)

~~~
dTal
That's an incredible paper! The supplementary materials are exquisite and can
be obtained here [0]. I'd very much like to get ahold of the enormous raw
dataset, but alas their margin was too small to contain it: "Owing to file
size limitations, no repository capable of archiving the entirety of the voxel
data for these scans currently exists".

[0]
[https://datadryad.org/stash/dataset/doi:10.5061/dryad.b451g](https://datadryad.org/stash/dataset/doi:10.5061/dryad.b451g)

~~~
grkvlt
I noticed that too; hopefully in the intervening 7 years these sorts of
limitations are no longer, but I suspect scientific data simply expandss to
fill the archive space available, and more ;(

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squibbles
"The juvenile sea squirt wanders through the sea searching for a suitable rock
or hunk of coral to cling to and make its home for life. For this task, it has
a rudimentary nervous system. When it finds its spot and takes root, it
doesn't need its brain anymore, so it eats it! (It's rather like getting
tenure.)" [0]

[0] Consciousness Explained, Daniel Dennett.
[https://www.google.com/books/edition/Consciousness_Explained...](https://www.google.com/books/edition/Consciousness_Explained/ZG0SDgAAQBAJ?hl=en&gbpv=1&bsq=The%20juvenile%20sea%20squirt)

~~~
mdonahoe
Do you recommend that book?

~~~
squibbles
If you are interested in consciousness, then yes, __Consciousness Explained
__is a worthwhile read. If your interest lies with sea squirts, then not so
much.

While I do not necessarily agree with Dennett's position in whole, I believe
his arguments make a valuable contribution to the subject of consciousness --
even moreso in the context of Wigner's thought experiment and the recent
empirical results.

~~~
DanielleMolloy
Would you mind sharing a pointer to the recent empirical results?

~~~
squibbles
Science magazine [0] and Ars Technica [1] published readable overviews. The
paper on the experiment regarding Wigner's friend paradox ("A strong no-go
theorem on the Wigner’s friend paradox") was published in Nature Physics. [2]
[3]

[0] [https://www.sciencemag.org/news/2020/08/quantum-paradox-
poin...](https://www.sciencemag.org/news/2020/08/quantum-paradox-points-shaky-
foundations-reality)

[1] [https://arstechnica.com/science/2020/08/quantum-reality-
is-e...](https://arstechnica.com/science/2020/08/quantum-reality-is-either-
weirdly-different-or-it-collapses/)

[2]
[https://doi.org/10.1038/s41567-020-0990-x](https://doi.org/10.1038/s41567-020-0990-x)

[3]
[https://www.nature.com/articles/s41567-020-0990-x](https://www.nature.com/articles/s41567-020-0990-x)

------
JackFr
The article is reminiscent of the some old science fiction tropes, about
_very_ different life cycles.

The article also reminded me of the chicken and egg inversion (I think from a
chapter in a Richard Dawkins book) -- the observation that chickens are merely
the mechanism through which eggs propagate themselves throughout the world.

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lordnacho
I looked up what makes an animal an animal. It turns that animals have to eat
another living thing to survive. It's quite interesting that the thing that
makes us animals is not the brain, limbs, heart, lungs, liver, etc.

It's having a stomach. Every animal has gotta do some sort of ingesting of
another lifeform. The sea squirt seems to be the prime example, it's just a
stomach. Everything else is replacable.

~~~
munificent
_> I looked up what makes an animal an animal. It turns that animals have to
eat another living thing to survive._

I'm not sure where you looked up the definition, but that is very much not
what defines animals.

There are plants like pitcher plants that eat living things, as well as many
bacteria that eat other living bacteria. And there are animals like earthworms
that only eat non-living organic material.

~~~
lordnacho
> Animals (also called Metazoa) are multicellular eukaryotic organisms that
> form the biological kingdomAnimalia. With few exceptions, animals consume
> organic material...

Assumes that meant living things?

Other things doing it too doesn't make a different, definitions we use for
words are gonna have grey zones, such is the reality of compression.

~~~
akiselev
"Organic material" as in organic chemistry as in compounds that form carbon-
hydrogen bonds - stuff made up mostly of hydrogen, carbon, oxygen, nitrogen,
and the halogens.

The correct term is _heterotrophic_ but even that is a fuzzy distinction
because many (if not most) plants require symbiotic bacterial/fungi colonies
due to nitrogen depletion and there are plenty of parasitic plants that can't
produce their own nutrition.

Clean classification of such abstract groups after billions of years of
evolution is impossible.

------
arfar
I know it's not actually relevant. But what a horrible website to read. The
grey text is soooo lacking contrast on the white.

------
lxe
So their larva is an almost-vertebrate (chordata) but then it changes back to
an invertebrate. Neato

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wwarner
Is this a case of regressive evolution (devolution)?

~~~
krapp
No, it's just regular evolution. It's a mistake to assume that evolution
prefers any particular direction, like increasing complexity or intelligence.

~~~
namenotrequired
Still, a species can evolve to be more similar to some distant ancestor than
to a certain more recent one. There's no mistake in asking if that is the case
here.

