[HN Gopher] Fruit eating possibly linked to primates' large brai...
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Fruit eating possibly linked to primates' large brain evolution
(2017)
Author : rajnathani
Score : 64 points
Date : 2022-08-26 05:22 UTC (1 days ago)
(HTM) web link (www.science.org)
(TXT) w3m dump (www.science.org)
| rajnathani wrote:
| From the NPR link [0]:
|
| > The researchers analyzed the brain sizes and diets of over 140
| primate species spanning apes, monkeys, lemurs and lorises and
| found that those who munched on fruit instead of leaves had 25
| percent more brain tissue, even when controlling for body size
| and species relatedness.
|
| [0]
| https://www.npr.org/sections/thesalt/2017/03/27/521423216/wh...
| culi wrote:
| Kinda funny to think about because leaf-eaters tend to have
| larger more complex gut microbiomes. Your gut microbiome has
| been called "the second brain" because the majority of
| neurotransmitters (including over 90% of all seratonin)
| originates there.
|
| It almost seems like there's a tradeoff between the two
| "brains"
|
| This would explain why pandas, koalas, and sloths (all leaf-
| eaters) are often thought of as "dumb" lol
| bpodgursky wrote:
| Can't really explain elephants in that case.
| culi wrote:
| Elephants actually do eat a lot of fruit as well. But yeah
| it was definitely a playful hypothesis and not a serious
| proposal. I'm sure if I researched it for even 10 minutes I
| could find a lot of examples that disprove it
| yababa_y wrote:
| The neurotransmitters in the gut do _not_ make it across the
| blood-brain barrier, and there certainly isn't a direct
| tradeoff between behavioural complexity and the stew of
| monoamines in your gut.
| tffcccdredf wrote:
| dataangel wrote:
| Prucalopride and other gut motility meds that contain
| neurotransmitters often have depression/suicide warnings,
| so some sort of information transmission is happening, even
| if it's not that the transmitters directly cross the
| barrier.
| nobody9999 wrote:
| >Kinda funny to think about because leaf-eaters tend to have
| larger more complex gut microbiomes. Your gut microbiome has
| been called "the second brain" because the majority of
| neurotransmitters (including over 90% of all seratonin)
| originates there.
|
| Leaf eaters _also_ tend to have larger jaw muscles and
| attachments for same.
|
| That tends to limit the size of the brain case, as that space
| is needed for the chewing apparatus and supporting skeletal
| features[0].
|
| [0] https://www.nature.com/articles/news040322-9
| culi wrote:
| Fascinating, thanks!
|
| I remember seeing a lecture by an anthropologist who showed
| a graph that mapped the size of different primates vs what
| percent of their day they spend just chewing food. Chimps
| spend about 60% of their days just chewing for example. The
| trendline was a surprisingly effective predictor for other
| primates. Except for humans. Based on our mass we would
| expect humans to spend around 70% of our day just chewing.
| Instead it's less than 10%
|
| Another point of evidence that supports the hypothesis put
| forth in the OP
| cbdc_watcher wrote:
| That's funny. If I had a bigger brain I too would munch on
| fruit instead of leafs. I think they have it backward causation
| wise.
| awestroke wrote:
| If you had a bigger brain, you would automatically have
| access to fruit? That seems backward causation wise
| xriddle wrote:
| Unlike glucose, fructose (sugar from fruit) is metabolized by the
| liver, and then converted to fat. Maybe fruit eaters were simply
| able to store more energy as fat which supplied the nutrition
| and/or extended survival required to evolve larger brains.
| pengaru wrote:
| > fructose (sugar from fruit)
|
| For posterity; sucrose (table sugar) is composed of half
| fructose, half glucose.
| DoreenMichele wrote:
| _The new study 's large sample size and robust statistical
| methods suggest diet and ecology deserve more attention_
|
| Maybe someone in need of a PhD thesis topic can do me a favor and
| spend some time scientifically looking at why _half_ of the human
| population lives within 200 km of the coast and what impact ocean
| minerals, including but not limited to salt, have on brain
| development at the species level.
|
| https://www.reddit.com/r/MapPorn/comments/uxrinu/half_of_the...
| 082349872349872 wrote:
| Iodized salt was actually a big public health thing in my non-
| coastal country.
| DoreenMichele wrote:
| Yeah, it's a thing in the US as well due to the Midwest being
| historically known as The Goiter Belt.
|
| I'm likely allergic to iodine, but have a genetic disorder
| that involves misprocessing NaCl -- "table salt" -- among
| other things (fats as well, which are also significant to
| brain development, what with the brain being the organ with
| the most cholesterol). And it happens to be a genetic
| disorder anecdotally associated with high IQs and indirectly
| associated with Nobel Prizes in that it is common in a
| population with a historically high percentage of of Nobel
| Prizes, outsized compared to the population in question.
|
| Anyway, I'm not good at doing "professional sciency speak"
| but I have reason to wonder about the role of salt (and
| related minerals) in brain development and IQ. Iodine is not,
| per se, one of the things making my radar in that regard.
|
| But thanks for replying
| rex_lupi wrote:
| It is also quite possible that harvesting fruits requires more
| brainpower (advanced spatial understanding, good memory, motor
| functions etc) which gave rise to the evolutionary pressure for
| cerebral development.
|
| [Hmm, seems authors have considered that possibility] but Further
| down the article:
|
| >He suspects that diet allowed, rather than drove, the evolution
| of big brains.
|
| Well, why?
|
| [Edit: removed question about (flying) frugivores, don't know how
| I missed the easy explanation, thank you] [
| lanstin wrote:
| They go into the fruit finding is harder than leaf finding in
| the article.
|
| flying creatures I would guess have a huge pressure to
| eliminate weight.
| echelon wrote:
| Even so, several bird species are among the smartest we know.
| Crows, parrots. I wouldn't call them _bird-brained_ as a
| pejorative.
| titzer wrote:
| Indeed, the Corvid family (crows, ravens) has been show to
| do some pretty complex problem-solving.
|
| I imagine that occupying a high perch out of danger and
| watching the goings-about by many creatures below, it helps
| to have a brain that figures out the behaviors of other
| animals, like squirrels, foxes, etc. That's a really
| theory-of-mind activity; modeling the thoughts of other
| animals (and the information available to each) to predict
| their behavior.
| swayvil wrote:
| >Also, why don't fruit eating birds or bats have big brains?
|
| Because big brains are aerodynamically impractical?
| dotancohen wrote:
| It would probably be more of a weight issue that an
| aerodynamic issue. And not for the brain itself, but rather
| for the strong neck necessary to support a large organ so far
| from the body's center of mass while in flight. It might put
| evolutionary pressure to reduce the neck length, which would
| have far reaching consequences for birds.
| stefantalpalaru wrote:
| freeslave wrote:
| Similar from a year ago:
| https://www.science.org/content/article/neanderthals-carb-lo...
| fire wrote:
| Sounds like this is in the same vein as the Cooking Hypothesis?
| Basically that control of fire led to cooking which led to
| greater nutrient acquisition from foods ( because more foods can
| be made edible, cooking reduces the energy cost of eating raw by
| "pre-digesting" them, and reduces losses by allowing the creation
| of basic broth style foods ) in turn leading to larger brains and
| our own evolution
| cbdc_watcher wrote:
| I heard that raw foods contain the very enzymes that our body
| uses to digest them. Like how an apple decays on its own over
| time. Those enzymes get destroyed during cooking so your body
| has to use its existing enzymes. Not sure if this is accurate
| information, so I'm mentioning it in case someone knows more
| about this subject.
| fire wrote:
| this almost sounds like you may be confusing it with natural
| digestive enzymes that are deactivated during cooking, like
| the kind that exists in pineapples to help it stave off
| insects ( if you eat them raw they'll digest part of your
| tongue and thus give you a raw tongue; heat deactivates those
| enzymes )
| bardworx wrote:
| In that case, why would we develop enzymes? We just always
| had them?
|
| And what about animals that eat only raw food? Does that
| imply that they wouldn't be able to digest cooked food?
| goldenkey wrote:
| > Fruiting bodies, also known colloquially as "shroomz."
| dukeofdoom wrote:
| I just find fruit trees to be extreemly beautiful. Especially an
| old rugged apple tree, or a fruitting peach tree or orange tree.
| Something about it clicks in my brain to release happy
| endorphins.
| rajnathani wrote:
| Also semi-relevant is the _Drunken monkey hypothesis_ :
| https://en.wikipedia.org/wiki/Drunken_monkey_hypothesis
|
| > Drunken monkey hypothesis proposes that human attraction to
| ethanol may derive from dependence of the primate ancestors of
| Homo sapiens on ripe and fermenting fruit as a dominant food
| source. Ethanol naturally occurs in ripe and overripe fruit when
| yeasts ferment sugars, and consequently early primates (and many
| other fruit-eating animals) have evolved a genetically based
| behavioral attraction to the molecule.
| amelius wrote:
| How does it relate to larger brains?
| ralusek wrote:
| We needed to evolve bigger brains in order to raise the floor
| of dumbness brought on by throwing back a few with the boys.
| number6 wrote:
| After a night of Ethanol my brain feels quite swollen.
| 8f2ab37a-ed6c wrote:
| Also the Stoned Ape Hypothesis:
| https://science.howstuffworks.com/life/evolution/stoned-ape-...
| biggerChris wrote:
| What a great username.
| xyzzy_plugh wrote:
| Humans aren't more attracted to ethanol than other mammals
| which do not regularly consume fruit. Give a dog or a horse or
| a goat or a racoon some booze and it'll be back for more (don't
| actually do this).
| umeshunni wrote:
| Elephants are known to get drunk and attack villages. https:/
| /www.google.com/amp/s/amp.theguardian.com/world/2010/...
| itisit wrote:
| Talk about a tragicomedy! Thanks for sharing.
| gregw134 wrote:
| Fyi that link is broken for me.
| tomxor wrote:
| Yeah weirdly redirects to a favicon
|
| [edit]
|
| Oh some weird google amp prefix, what is this supposed to
| do?
|
| here's the real link:
| https://www.theguardian.com/world/2010/dec/03/elephants-
| drun...
| tsol wrote:
| Even fruit flies can get drunk.
| coldtea wrote:
| > _Humans aren 't more attracted to ethanol than other
| mammals which do not regularly consume fruit_
|
| Well, it's not about attraction "given the chance", but about
| persistent attraction. In other words, "other mammals" might
| also by chance consume alcohol (or ripe fermented fruit) and
| get drunk and like it, but they didn't pursue it actively or
| have alcoholics...
| CodeSgt wrote:
| Other mammals aren't intelligent enough to do so.
| [deleted]
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