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.
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't quite tool use but recognizing tools unlike anything in nature and how to manipulate them to get what they want.
Hermit crabs have both and live in large social groups and eat a diverse diet as well.
Many hermit crabs will come together and work as a team to change shells in hierarchy. If you've never seen it, you are in for a treat.
That one crab was caught with its pants down for a moment.
First I think you're getting the cause/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.
So the question isn't so much "what causes complex intelligence" (your proposal being hands) but rather "why hasn't complex intelligence appeared for something like the gazelle family tree?"
It's an interesting hypothesis to say that perhaps it's because they don'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.
I'm not a biologist though so take what I'm saying here with a gigantic grain of salt.
We agree that it can be difficult to distinguish causation from correlation, and in this case you may be right that the survival advantage conferred by better grasp of branches might have been a "bonus" or helpful side-effect, rather than an adaptive trait directly informing our ancestors' evolution. But I don't think it's so clear-cut or obvious.
When you talk generation to generation, the gradual tiny mutation each time did indeed allow primates to grab the branches a little better and so they had a higher rate of survival and the causation matters.
But when you talk about the end product (the hand), it is fair to say that primates (as the product of those millions of tiny iterations) evolved to better grab branches, imo.
But on the other hand, some of the kludginess is also bloody amazing. Spiders, for example. The gut passes through the "brain". So there's a tradeoff between "brain" size and eating. And so they employ external digestion, and suck liquid.
The first part is that brains are just plain weird, and perhaps one of the weirdest aspected of any multicellular organism. More than half of all known life forms don’t have brains. So, brains usually aren’t a priority.
Second, the gut is often regarded as a brain-like organ in many vertebrates, and so, with arthropods and crustaceans, it’s interesting that the the two might be more tightly coupled. It probably cheapens the endocrine feedback loop.
Third, external digestion actually comes across as less freakish and uncivilized underwater. On land it has a messy, disgusting sensibility, but in the ocean it’s kind of on par with a smokey cooking fire at a camp site, especially when considered from a single celled animal’s perspective.
When you consider that crabs and lobsters are the ancestral relatives of insects and arachnids, the low prioritization of a brain, and externalized digestion start to look more and more normal.
In all invertebrates, "brains" (to the extent that they're present) are ring ganglia, with the gut going through the center. So arguably they all face that tension between brain development and the ability to eat. Vertebrates, conversely, have ~parallel guts and central nervous systems, so there's no conflict.
The thing with octopuses is that their ring ganglia are mode widely spaced. Having no exoskeleton helps with that, I guess.
Corvids are among the most intelligent animals in the world. In many cases far more intelligent than many ape species. Their brains are the size of almonds, at largest. Whale species are intelligent but their brains are incredibly massive. Whales aren't 10-100x more intelligent than humans because of brain mass.
The intelligence level of Neanderthals is unknown but they had a cranial volume approximately 22% larger than modern humans. The common knowledge is that Neanderthals went extinct because they were stupid and eventually killed off by human invaders. The current evidence is that Neanderthals and humans overlapped in Europe for roughly 5000 years and heavily interbred with humans. The most likely cause of extinction had nothing to do with intelligence. They likely died off because the evidence indicates they were less social and reproduced less frequently. If anything they may have been comparatively too smart for their own good.
Large animals aren't just scaled up versions of smaller animals. Large animals use the space for more complicated digestive tracts. Their larger appendices allow them to have more joints with more degrees of freedom, and longer appendices and higher speeds require a higher resolution from their eyes to perceive sufficient detail. Skin with more surface area also means many more cells for sensing heat, pressure, damage, etc across the entire skin.
All of this means the brain of a larger creature needs more "IO ports", more neurons to compute sensible outputs for them even for routine tasks, and more neurons to break the wealth of data into a form usable by a cognitive process or an instincutal reaction (mapping to area of body, computing averages over time and over multiple inputs, correlating different types of senses, etc).
All of these differences have different scaling factors. The amount of neurons to count to 5 stays the same, the amount of neurons to process skin sensations scales approximately with skin area, or the square of animal diameter, but the amount of neurons to control motor functions or the digestive tract can grow much faster. Overall, putting brain size in relation to animal size or mass is a decent first approximation and works in practice.
why absolute size doesn't matter as much as we think it should is a really good question, but clearly our modern transition from "the nervous system is like a steam engine" to "the brain is like a computer" is only an improvement and not actually a good model yet.
So, when "one thinks of compute capacity" one arrives at the wrong answer instead of one that fits the evidence and statements of the evidence seem like "a strange argument".
It's more about if it's possible for minute intelligence improvements to produce higher survival chances. For a gazelle, the intellect leap needed to be substantial, and random genetic mutations weren't going to get there. For an octopus, each little intellect bump meant little survival bumps too.
d(SurvivalGazel) = 0.001 dIntelligence
d(SurvivalOctopus) = dIntelligence^2
We have an expression (aphorism), something like "clever enough to be dangerous".
Intelligent enough to experiment, but not too realise the dangers involved is relatively common in humans; the societal system in the past mitigated the dangers by pairing younglings with adults who can tell them when they're being dumb.
Not a great source, but here's an excerpt explaining that they tend to grow up in groups:
But growing up is a different story. During younger years, they often live in larger flocks dubbed juvenile gangs. "It's exactly how it sounds: they're basically a bunch of teenagers trying to compete with each other," Brown says. And it's these relationships they have to keep tabs on.
Humans may be unique in having both complex social structure as well has hands.
I guess Niven and Pournelle had the same idea for Footfall.
So, yeah octopodes are really cool, but it's not correct to say that octopodes evolves intelligence and chromo-camouflage in some sort of direct way because they needed to become intelligent: what would have happened was over a very long time, certain families or society started being born with more than above intelligence, which allowed them to get better access to food and mates, which meant they were fitter, which meant they may pass on their advantageous traits their children, who would carry it on the their children etc.
Evolution doesn't happen "because" of something. Wales didn't evolve into marine mammals because they needed more food. Yes, they needed more food but their evolution just randomly moved their species towards the water.
For example a terrestrial wale may have been born with the ability to hold its breath, just by chance. Eventually every terrestrial wale has inherited that ability, and then the process repeats, with another mutant wale evolving thicker blubber which would allow it to obtain more food, spend longer in the water end pass on their trait for blubber.
There isn't a "because".
And, of course, they're just interesting creatures regardless. Their bodies is flexible, yet strong, like one continuous muscle. Each tentacle has a slightly different "personality;" for a single octopus, some of its tentacles are more adventurous while others are more shy. They can change the color of their entire body, and do, for reasons we haven't figured out yet. They mate once, after which the female guards the egg cache without moving from the spot until she withers away.
Everything I read about them absolutely floors me. They're the closest thing we have to an intelligent alien species.
We're quite close to dolphins and killer whales, so the essence of their intelligence is easier for us to understand, because they are more like us.
Bees, termites, ants, etc. are really interesting because any individual is pretty stupid, but the entire swarm is complex and intelligent.
I don't need to concentrate on finger or hand movements while I'm typing this. My brain thinks about the words while it delegates the details to other systems. There's an incredible amount of processing involved in operating human limbs which we're mostly unaware of.
I'd guess octopus consciousness is similar - goal oriented, with delegation. I'm mot sure, given the relatively small distances involved, if the slight physical separation of the central and distributed brains would make a huge difference to having an all-in-one model with distinct areas squished up inside a single unit.
But I absolutely agree - they are amazing and fascinating. If they were more social they'd probably be running the planet.
Humans have two semi-autonomous brain hemispheres, each with a slightly different personality.
Personally I am impressed that cephalopods can be as intelligent and resourceful as they are while being cold-blooded, though I suppose tropical species don't suffer much from that problem.
it's fascinating. they also filmed this in blue planet ii.
that clip unfortunately cuts off the first part where the shark caught the octopus, but the octopus put its arms in the sharks gills so it couldn't breathe and got away.
A succesful splashdown, reasonable adaptation to the local conditions — and a fatal flaw speeds up development enormously, bodies replicate and die long before their brains mature. The culture is lost, the invaders turned into animals doing primitive hunting.
They divide biomass up into three environments, with 6 Gt C in "marine", 70 Gt C in "deep subsurface" and 470 Gt C in "terrestrial". You can also see in their analysis that the huge biomass bias towards the land is due to plants and fungi, which overwhelmingly favour the land; among animals there is actually more biomass in the oceans.
> Intriguingly, using chromatic aberration to detect color is more computationally intensive than other types of color vision, such as our own, and likely requires a lot of brainpower, Stubbs said. This may explain, in part, why cephalopods are the most intelligent invertebrates on Earth.
A notable advantage of everse eye construction is the complete absence of a blind spot, which is where all the wiring passes through the sensor surface. (Image sensors never had that problem because they are connected at the edges).
The location of the ‘wiring’ changes the type of information gleaned from the light field. There is no ‘wrong,’ rather, a variation in local optimization.
Their nervous systems are more like spiders than vertebrates.
So if you love Portia, I recommend Peter Watts' Echopraxia and (for a full-length focus) Adrian Tchaikovsky's Children of Time.
This book really made me realise (once again) how strange and wonderful good science-fiction can be.
It's absolutely amazing, I love how the author constructed a civilization of sentient, tool-using beings that's qualitatively different than humans. It's one of the most original books I've ever read, and it rekindled my interest in insects.
[digs up his copy]
Edit: Doh. I last read that so long ago that I'd forgotten that they were large spider-like beings :)
... and yes, they hop, so maybe Portia. But I don't recall that Vinge ever says so.
Octopus keepers usually keep a second aquarium to grow the octopus's food. So add that to the expense.
Negatives, there are a few. But on the positive, amazing lifespan:size ratio!
Don't keep an animal that had to be captured and removed from its natural habitat.
Also be very, very sure you can take care of the bird for the rest of your life, and will have someone that can take over when you die who the bird will already know and be friendly with. Birds are more work than dogs, they need a whole room in your house (at least) to be made safe to fly around in / shred things in, etc. Don't leave a parrot alone with anything you want intact.
All that said they can be very friendly & great companions.
To be clear, the reason is that parrots bond (with their owner, if alone) for life.
(Don't know why you were downvoted.)
I sometimes think the account of evolution of man you tend to get in popular science writing may have things backwards - it tend to be our ancestors got good at hunting which allowed us to evolve larger brains but I'd imagine it was quite likely that a random mutation made our ancestors smarter first, then there were behaviour changes then we evolved some superficial changes such as changes in size and shape of some parts.
Computers struggle to handle a single genome, let alone mix and match multiple. And even when they do, it's a single organism. In nature, there are thousand's of organisms mixing and matching, thriving and dying all the time, spread over hundreds of millions of years.
No computer's bandwidth could come close to that.
But I have a deeper discomfort with your question. It assumes that the neural network / tensor-flow model we use with computers approximates a human's. I'm not terribly convinced of that.
Sure, human neuron's have are individually approximated by neural network neurons. But concepts such as "instinct" are not captured well by that model.
It's weird that a newborn baby has seen far fewer colors, and patterns than a well trained neural network, yet seems to know far more. It signifies we're missing something pretty central to the model.
"The evolution from squid to octopus is compatible with a suite of genes inserted by extraterrestrial viruses. An alternative extraterrestrial scenario discussed is that a population of cryopreserved octopus embryos soft-landed en mass from space 275 million years ago."
It talks about number of neuron and why cooked food helps us in giving the energy required for the large number of neurons. Also cooked food gives us free time to think. (edited for clarity)
Signed by 33 authors and published in a peer-reviewed, seemingly established journal. Thanks for the pointer!
You probably don't need the warmth underwater, but cooking facilitates nutrient absorption ("exodigestion"?), wards off predators, post-sunset light, and (later) smithing, smelting, steam power etc.
A real world example of this is the isolated tribe of North Sentinel Island (who recently killed an American Christian missionary who smuggled himself there to prosyletize).
As best we can tell, they appear to not have learned to harnessing fire to this day.
EDIT: although the first anthropologist to contact the Sentinelese claims otherwise:
Maybe even held weapons for striking enemies. You can't swing a club underwater due to water resistance, and spears are hard to use well because you don't have feet planted to transmit the force, so you just go backwards if you try to stab something. Not to mention the lack of trees and branches with straight poles.
Meanwhile stone tools and weapons are too heavy to carry. You'll sink.
In fact every tool would either sink or float, and incur huge drag. Which makes tool use much harder overall.
Poison will dissolve and drift away within moments of applying to a projectile.
Nothing to make the tube out of.
You don't have lungs (water respiration doesn't work this way in any creature I know of), so you can't "blow" anything.
You might have heard about mantle, an organ that distinguishes mollusks. Many of them use it to circulate water around the gills and some are so good with it that they can create a water jet and shoot it with such a force that they swim in the opposite direction.
For instance, if you have a container full of hermit crabs, shells, and other debris, nearly 100% of the crabs will adorn themselves with a shell, because of the instinctual drive to protect their carapace.
While if you were to repeat the same exercise, but with octopuses instead of crabs, the octopuses will find shelter in many different and creative ways. Some will find crevasses, while others will wear a shell like their ancestors (though this isn't likely instinct, since ancient cephalopods grew their shells, instead of hunting for them). Some will even live in a shell, and then find a "door" to cover the entrance with.
Combine with evidence of mechanical aptitude, from experiments where octupus are given food in locked containers, it's pretty clear they have a deep understanding of the world around them. For example you can give an octopus a meal in a threaded jar, and after some initial experimentation, they will reliably get to the food. The second time, it will immediately unthread the jar without experimentation, suggesting that it learned the "trick." Keep in mind, very few animals physically capable of opening a jar are actually smart enough to figure out how jars work, so this is very impressive.
Another interesting example, wild octopuses favorite food is crab, they will seek out fisherman's crab traps in the wild, open the latch mechanism, then gorge themselves on all the trapped crab inside. They are the only animal I know of that will do this.
Arguably, there is no "why".
You could say that they're an evolutionary dead end. But that's just speculation.
It also assumes free will in asking the quesiton.
I was thinking generally about the fallacy of seeking intentionality in evolution. There is a point to analyzing what happened, of course. It's just that too much "why" is dangerous.
Why ("how come")? Is a legitimate question, though. What selective pressure is there in the environment that would lead to dumber octopuses dying off while smarter ones thrive?
You're totally right. Asking questions and thinking about things might lead you to dangerous places. You might even (gasp) eventually start believing in God. That would be doubleplus ungood crimethink!