<story><title>The Octopus Is Smart as Heck, But Why?</title><url>https://www.nytimes.com/2018/11/30/science/animal-intelligence-octopus-cephalopods.html</url></story><parent_chain><item><author>jaggednad</author><text>One theory why primates evolved big brains is because they had hands. Big brains for an animal like a gazelle don’t pay off because, without hands, there isn’t much a gazelle can do with that big brain. Better it use that energy for bigger leg muscles. Primates evolves hands so they could better grasp branches, but, once they had hands, there was a lot more they could do with them, like make tools. A bigger brain for a creature with hands is an evolutionary advantage, because that bigger brain allows complex behaviors that can be carried out with hands. I bet octopuses are intelligent for a similar reason. Its body is like one big hand, and there are lots of complex behaviors it can carry out with those tentacles. Similar for its color changing skin. There are many complex and useful ways that skin can be used, so it pays to have a big brain. The important point is that the bodily appendages came first, and those appendages made it actually useful to have a big brain. I find it more surprising that dolphins became intelligent, but the article is right that living in groups capable of communication and cooperation can similarly make big brains pay off, because the animal can engage in complex group behaviors.</text></item></parent_chain><comment><author>Nasrudith</author><text>Well I think the bigger issue for gazelles is energy density period - brains are calorie hogs and it doesn&amp;#x27;t take much cunning to track down grass. Grass eating is the opposite direction in a food strategy - going for abundant but low density food instead of chasing higher density.&lt;p&gt;A diverse diet is a bit of a hallmark of intelligence in itself in that they are able to use their brains to get more food to make it worth the investment - similarly to complex group behavior I guess.&lt;p&gt;Hermit crabs for instance are shockingly intelligent for crustaceans, especially for ones of their size. I know that improperly shut lids which while closed have enough play - they cold push from the inside causing them to rotate on their axis and let them escape. That isn&amp;#x27;t quite tool use but recognizing tools unlike anything in nature and how to manipulate them to get what they want.&lt;p&gt;Hermit crabs have both and live in large social groups and eat a diverse diet as well.</text></comment>
<story><title>The Octopus Is Smart as Heck, But Why?</title><url>https://www.nytimes.com/2018/11/30/science/animal-intelligence-octopus-cephalopods.html</url></story><parent_chain><item><author>jaggednad</author><text>One theory why primates evolved big brains is because they had hands. Big brains for an animal like a gazelle don’t pay off because, without hands, there isn’t much a gazelle can do with that big brain. Better it use that energy for bigger leg muscles. Primates evolves hands so they could better grasp branches, but, once they had hands, there was a lot more they could do with them, like make tools. A bigger brain for a creature with hands is an evolutionary advantage, because that bigger brain allows complex behaviors that can be carried out with hands. I bet octopuses are intelligent for a similar reason. Its body is like one big hand, and there are lots of complex behaviors it can carry out with those tentacles. Similar for its color changing skin. There are many complex and useful ways that skin can be used, so it pays to have a big brain. The important point is that the bodily appendages came first, and those appendages made it actually useful to have a big brain. I find it more surprising that dolphins became intelligent, but the article is right that living in groups capable of communication and cooperation can similarly make big brains pay off, because the animal can engage in complex group behaviors.</text></item></parent_chain><comment><author>warent</author><text>When you&amp;#x27;re saying &amp;quot;Big brains&amp;quot; I assume you mean a higher level of cognition and awareness in some general sense, not a physically larger brain.&lt;p&gt;First I think you&amp;#x27;re getting the cause&amp;#x2F;effect of evolution backwards. For example, primates did not evolve hands so they could better grasp branches, but rather they better grasp branches because they evolved hands and so had a higher rate of survival.&lt;p&gt;So the question isn&amp;#x27;t so much &amp;quot;what causes complex intelligence&amp;quot; (your proposal being hands) but rather &amp;quot;why hasn&amp;#x27;t complex intelligence appeared for something like the gazelle family tree?&amp;quot;&lt;p&gt;It&amp;#x27;s an interesting hypothesis to say that perhaps it&amp;#x27;s because they don&amp;#x27;t have hands, but there are innumerable other factors that could also be an influence, I doubt it comes down to a lack of hands.&lt;p&gt;I&amp;#x27;m not a biologist though so take what I&amp;#x27;m saying here with a gigantic grain of salt.</text></comment>