[Coral-List] Yes, the Octopus Is Smart as Heck. But Why?

Thu Dec 13 22:10:32 UTC 2018

    Well, surely saying it has a large or small brain depends on what it is
being compared to.  Compared to invertebrates it has a large brain, but
compared to most mammals and even a few fish it has a small brain.  Human
brains weigh about 1300-1400 g, sperm whales 7800 g, elephant 4783, dog 72,
great white shark 34, nurse shark 32, tree shrew 3, rat 2, house sparrow 1,
turtle 0.3-0.7, bull frog 0.24, viper 0.1, green lizard 0.08, goldfish .1 (
https://faculty.washington.edu/chudler/facts.html) and Octopus brain about
1 g (http://www.kheper.net/topics/intelligence/cephalopod_brainsize.html)
     A mouse brain is about 1 cm diameter, an octopus brain appears to be
about 8 mm long and a bit less than that wide.  So I was in error, it is
more the size of a grape than a grain of rice.  Two thirds of the Octopus's
500 million nerve cells are in the arms, and 40-45 million in it's brain
(not counting the optic lobes which are separate but close to the brain,
including them would boost it to around 160-180 million).  The sea slug
Aplysia has about 20,000 nerve cells in it's entire nervous system (Hochner
et al, 2006), some of which are huge.  Humans have about 500 billion nerve
cells.
   Cheers,  Doug

Hochner, B., Shomrat, T., Fiorito, G.  2006.  The Octopus: a model for a
comparative analysis of the evolution of learning and memory mechanisms.
Biological Bulletin 210: 308-317.  (see Google Scholar)

https://www.scientificamerican.com/article/the-mind-of-an-octopus/

On Wed, Dec 12, 2018 at 5:27 AM Eduardo Sampaio <edusilvasampaio at gmail.com>
wrote:

> Hi all,
>
> Just want to give some feedback on this interesting discussion. Octopuses
> do not have small brains, especially in brain/body relation. They are the
> only invertebrates which brain-body relative size rivals that of
> vertebrates (see for example J.Z. Young's papers from last century). Plus,
> as many of you were saying, 2/3 of their 500 million neurons are located
> outside of the brain, since they evolved from "ladder" architectures, in
> opposition to the centralized architecture of vertebrates. Thus, this
> actually makes up for a higher number of neurons then at least some
> vertebrates have, which made some researchers start studying the concept of
> "distributed intelligence".
>
> What makes cephalopod researchers most puzzled is finding the evolutionary
> need for such a short lived animal (most live up only to two years), to
> invest so much in neural tissue and cognitive capacities. Most research
> points to the losing of their external shell as the primary factor for
> this, but this is still a subject of much discussion.
>
> All the best,
> Eduardo
>
>
> On Wed, Dec 12, 2018, 16:42 Matt Nolan via Coral-List <
> coral-list at coral.aoml.noaa.gov wrote:
>
>> Why?
>>
>> My guess is they got the key random genetic permutation in the genome
>> that gave their brain the unique circuitry needed to be smart.
>>
>> They were evolving and they hit the random mutation jackpot.
>>
>> And the challenging nature of their environmental aided in the change
>> sticking because it was an advantageous change.
>>
>> of course, the specifics of the genetic change, is the interesting part
>> On Mon, Dec 10, 2018 at 9:23 AM Douglas Fenner
>> <douglasfennertassi at gmail.com> wrote:
>> >
>> > It has eight arms, three hearts — and a plan. Scientists aren’t sure how
>> > the cephalopods got to be so intelligent.
>> >
>> > Read More... <https://nyti.ms/2DTnFOa?smid=nytcore-ios-share>
>> >
>> > They talk about big brains, but actually Octopus and other cephalopods
>> > don't have big brains, their brains are about the size of a rice grain.
>> > Which just makes their intelligence all the more surprising and
>> puzzling,
>> > it seems to me.  But the cephalopods are all fabulous creatures.
>> >
>> > There are links to several other interesting cephalopod stories at the
>> end
>> > of this story.
>> >
>> > Cheers, Doug
>> > --
>> > Douglas Fenner
>> > Ocean Associates, Inc. Contractor
>> > NOAA Fisheries Service
>> > Pacific Islands Regional Office
>> > Honolulu
>> > and:
>> > Consultant
>> > PO Box 7390
>> > Pago Pago, American Samoa 96799  USA
>> >
>> > Global warming will happen faster than we think.
>> >
>> > https://www.nature.com/articles/d41586-018-07586-5
>> >
>> > Nations falling short of emissions cuts set by Paris climate pact,
>> analysis
>> > finds
>> >
>> >
>> http://www.sciencemag.org/news/2018/11/nations-falling-short-emissions-cuts-set-paris-climate-pact-analysis-finds?utm_campaign=news_daily_2018-11-28&et_rid=17045989&et_cid=2515903
>> >
>> > Climate change poses major threat to the US, new government report
>> concludes
>> >
>> >
>> http://www.sciencemag.org/news/2018/11/climate-change-poses-major-threat-us-new-government-report-concludes?utm_campaign=news_daily_2018-11-26&et_rid=17045989&et_cid=2511504
>> > _______________________________________________
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>> > Coral-List at coral.aoml.noaa.gov
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>

-- 
Douglas Fenner
Ocean Associates, Inc. Contractor
NOAA Fisheries Service
Pacific Islands Regional Office
Honolulu
and:
Consultant
PO Box 7390
Pago Pago, American Samoa 96799  USA

Global warming will happen faster than we think.

https://www.nature.com/articles/d41586-018-07586-5

Nations falling short of emissions cuts set by Paris climate pact, analysis
finds

http://www.sciencemag.org/news/2018/11/nations-falling-short-emissions-cuts-set-paris-climate-pact-analysis-finds?utm_campaign=news_daily_2018-11-28&et_rid=17045989&et_cid=2515903

Climate change poses major threat to the US, new government report concludes

http://www.sciencemag.org/news/2018/11/climate-change-poses-major-threat-us-new-government-report-concludes?utm_campaign=news_daily_2018-11-26&et_rid=17045989&et_cid=2511504