Sapient Spiders--as if they weren't bad enough already

[Jendekit]

Over in World-Building, there was a thread about asking anthropology, geology, biology, etc. based questions. One of them (from myself) was about a race of sapient spiders. I have a loose idea of how they evolved:

Tarantula-esk starting point
Complicated web designs were seen as sexually attractive
Brains grew and became more intelligent to facilitate more complex webs

I know that at some point they would develop some level of social capabilities, but I'm having difficulty figuring out how that would evolve to the level of using a web-based Morse Code or having villages made out of silk (both of which happen at some point).

Suggestions?

[GloatingSwine]

Fortunately for your nightmares, there's only so big a spider can get. And that means only so big its brain can be, which puts a crimp on the whole intelligence deal. (Also it tends to be the smaller spiders that live socially anyway)

So, it's not the sort of thing that would evolve naturally, so just make up something that fits the world and narrative and use the appropriate local flavour of magic to make it work.

[NecroRebel]

Arthropods' respiratory system is the primary reason why they can't get terribly large as I understand it. They just simply cannot absorb enough oxygen to survive if they're beyond a certain size, which depends on the amount of oxygen in the atmosphere. In short, either your spider-folk will have to be little larger than tarantulas, the natural oxygen levels of your world will have to be much higher (which will have other consequences), or your spider-folk will need to have a radically different form of respiration than natural spiders.

While the third option is probably the best, there's... really no conceivable way for a very different form of respiration to evolve when a form of respiration already exists. You'll probably have to go with the old fallback, "it's magic." I'd probably go whole-hog on that and just outright give them magical means of respiration in general, making it so they naturally don't breathe as a special ability.

[Yora]

The breathing is only an issue of we insist to still call it a spider.

Go back 500 million years and look at the animals and you could say "these could not go on land because their breathing system only works in water. But evolution changed how they breath and now they can. Might be covergent evolution, but many of those aquatic animals look a lot like scorpions and centipedes. And O think spiders are actually somewhat related to crabs.
So I don't see any reason why spiders would be unable to evolve lungs and a circulatory system. Even though that would take millions of years. A creature that looks like a spider on the outside, but quite different on the inside should not be a big stretch evolutionary. Debatable if it would be classified as a spider biologically, but for a fantasy world that is not an issue.

And since nobody in that fantasy world would know about the evolutionary history of animals, it's not actually necessary, or even useful to write it down.

[The Random NPC]

I remember watching some speculative documentary on what would happen if humans just left Earth, and one of the things they described was some kind of hivemind spider colony that spun large webs to catch seeds, which they stored to feed mice, which were their livestock.

[Tvtyrant]

I remember watching some speculative documentary on what would happen if humans just left Earth, and one of the things they described was some kind of hivemind spider colony that spun large webs to catch seeds, which they stored to feed mice, which were their livestock.

Full bore nightmare fuel. We don't have a run screaminh from the room smiley, so I will make due with gagging slightly in real life. On the oxygen thing, crusteaceans have fewer size limits and can get much bigger. Make them sea spiders.

[weaseldust]

If spiders were social animals like ants they could solve the respiration problem by having a caste devoted to growing big brains at the expense of all their other organs. If they didn't have to move, breed, or find or digest their own food they could be, say, 4 kilo sessile animals with 2 kilo brains (about the same as a human). That might be supportable with only book lungs. Presumably there would be another caste for gathering food (and chewing it up and feeding it to the brain caste), and another for fighting, and a queen for breeding, and maybe a special caste for making stuff out of web. The brain caste could communicate orders to the others via pheromone.

I seem to remember that some male spiders introduce themselves safely to potential mates by tapping on their webs in a certain way. So there's some precedent for communication-via-web.

[The Random NPC]

Found it, it's call The Future is Wild (http://en.wikipedia.org/wiki/The_Future_Is_Wild).

[GloatingSwine]

Arthropods' respiratory system is the primary reason why they can't get terribly large as I understand it.

One of them. The other is that they have an exoskeleton*, as you scale up an exoskeleton it becomes significantly more massive (because surface area doesn't scale linearly), to the point that a creature with one will basically be crushed under the weight beyond a certain size.


* Spiders have an endoskeleton as well, unlike insects, but they'd basically have to ditch the exoskeleton beyond a certain size.


I remember watching some speculative documentary on what would happen if humans just left Earth, and one of the things they described was some kind of hivemind spider colony that spun large webs to catch seeds, which they stored to feed mice, which were their livestock.

They're already doing that. (http://www.wired.com/2014/10/4-acre-spider-web-engulfs-building/).


If they didn't have to move, breed, or find or digest their own food they could be, say, 4 kilo sessile animals with 2 kilo brains (about the same as a human). That might be supportable with only book lungs.

Running a human sized brain would be a nontrivial task for a small creature. The brain uses about 20% of a human body's energy to operate, so in order to run it you probably couldn't just have it be half the creature because you need more digestive system, external digestion may be insufficient, and you need an efficient way of accessing food calories that are normally lost, and because you have to run the brain all the time just lying around digesting forever like snakes probably not good enough, you need throughput! Also, because surface area is a significant property of brain function and that means more circulatory load you need to have a better circulatory system (so book lungs and hemolymph probably aren't enough, you need veins and you probably need to swap the hemocyanin for hemoglobin)

So it's actually pretty damn hard to run a human sized brain without the rest of a human sized animal doing life support for it.

Not that the image of a big fat spider where the abdomen is all wrinkled with brain ridges isn't awesome and someone should draw one to horrify the internet with.

It just doesn't work without magic.

[weaseldust]

Running a human sized brain would be a nontrivial task for a small creature. The brain uses about 20% of a human body's energy to operate, so in order to run it you probably couldn't just have it be half the creature because you need more digestive system, external digestion may be insufficient, and you need an efficient way of accessing food calories that are normally lost, and because you have to run the brain all the time just lying around digesting forever like snakes probably not good enough, you need throughput! Also, because surface area is a significant property of brain function and that means more circulatory load you need to have a better circulatory system (so book lungs and hemolymph probably aren't enough, you need veins and you probably need to swap the hemocyanin for hemoglobin)

So it's actually pretty damn hard to run a human sized brain without the rest of a human sized animal doing life support for it.

Not that the image of a big fat spider where the abdomen is all wrinkled with brain ridges isn't awesome and someone should draw one to horrify the internet with.

It just doesn't work without magic.

You are probably right about the circulation issues, though I still think digestion wouldn't be a problem if they are constantly being fed by worker spiders. Honeypot ants already have a system where some ants are specialised workers responsible for feeding sugar-water to others.

What if the brains of the brain spiders were exposed to the air and worker spiders could come up and spray sugar-and-oxygen-rich spittle on them to keep them supplied with energy? Then they wouldn't have such a problem with circulation.

EDIT: Alternatively, the spiders could paralyse mammals and lay eggs in them. Then the metabolism and circulatory system of the paralysed mammal could support the spider(s) growing inside it. They'd need to evolve some way to make the mammal capillaries penetrate their bodies and avoid being attacked by the mammal's immune system, though.

[Jendekit]

...since nobody in that fantasy world would know about the evolutionary history of animals, it's not actually necessary, or even useful to write it down.

It's more for personal interest and curiosity than anything else. I try to avoid just handwaving how something could exist in my settings in my headcannon at least. I like to have some sort of history for how something like that could occur.

For example, the orcs in the current setting that I am working on are actually a relative of humans much like Neanderthals. Whether they are the descendants of neanderthals or not I have not decided. One race was created from forcefully merging early human tribes with serpents, another was from a similar situation with pumas instead of snakes. The only other major race at this point are Dhampirs which out-competed humans in their homeland due to an overabundance of vampires (vampires in this setting universally Look Like Orlok (http://tvtropes.org/pmwiki/pmwiki.php/Main/LooksLikeOrlok) as a side note). So every major race has a headcannon biological history.

[Gritmonger]

Instead of web-building, you could look at Jumping Spiders - they are complicated in terms of behavior. Most other spiders, the male is a tiny thing that has to sneak up on the female as part of its strategy: she has no brakes on her aggressive instincts, no complex behavior. Not supported by most spider-minds.

Jumping spiders, on the other hand, have complicated couring rituals. The male has usually brighter and more decorative front legs, and will wave them, semaphore-fashion, to signal to a female that he is not a threat or prey but a suitor. They are, among spiders, what we would associate as "curious" - they look first rather than jump first, and unlike most other jumping creatures they are quite precise in the start and end point as well as throwing a safety line.

Salticidae, I think the group is called. Among spiders, there are actually some that might be classified as "cute." When looking for intelligent species, look at behavioral complexity or adaptive behavior.

[The Random NPC]

...They're already doing that. (http://www.wired.com/2014/10/4-acre-spider-web-engulfs-building/)....

Yes, but are they farming livestock?

[hamishspence]

So it's actually pretty damn hard to run a human sized brain without the rest of a human sized animal doing life support for it.

Kaldanes in the Edgar Rice Burroughs Mars books were a bit like that - spidery creatures, nearly all brain - which had co-evolved as symbiotes with a humanoid creature with virtually no brain.

[Starwulf]

Yes, but are they farming livestock?

I am absolutely with the top comment on that article. Can't repeat it here due to cursing, but yeah, to hell with that. If I walked into a building and saw that many spiders and that much spider web, I'd run out of the screaming, probably with pee leaking down my leg and poop piling up in my underwear, with a bare hold on my sanity.

[Winter_Wolf]

I am absolutely with the top comment on that article. Can't repeat it here due to cursing, but yeah, to hell with that. If I walked into a building and saw that many spiders and that much spider web, I'd run out of the screaming, probably with pee leaking down my leg and poop piling up in my underwear, with a bare hold on my sanity.

I don't think regular fire is gonna be enough for my sense of sanity. We're talking napalm, greek fire, thermite, the works. I'd be afraid to demolish the building because then instead of all gathering inside of an enclosed structure, they'd be free to roam. I still get the heebie jeebies when I remember walking on a wooded trail and realizing that the entire forest floor was moving because it was all spiders. I think that it's probably a blessing that nearly everything in my brain kind of shut down so that the only real thought processes were, "keep moving" and "get the heck out of here right now." And then I walked into/"discovered" a graveyard. Man that was one hell of a day hike.

[GloatingSwine]

Instead of web-building, you could look at Jumping Spiders - they are complicated in terms of behavior. Most other spiders, the male is a tiny thing that has to sneak up on the female as part of its strategy: she has no brakes on her aggressive instincts, no complex behavior. Not supported by most spider-minds.

Jumping spiders, on the other hand, have complicated couring rituals. The male has usually brighter and more decorative front legs, and will wave them, semaphore-fashion, to signal to a female that he is not a threat or prey but a suitor. They are, among spiders, what we would associate as "curious" - they look first rather than jump first, and unlike most other jumping creatures they are quite precise in the start and end point as well as throwing a safety line.

Salticidae, I think the group is called. Among spiders, there are actually some that might be classified as "cute." When looking for intelligent species, look at behavioral complexity or adaptive behavior.

They're the most photogenic of spiders because the little red light preceding a camera flash gets their attention as possible prey, so they turn to look into the camera with their main front eyes.

http://i.dailymail.co.uk/i/pix/2012/07/02/article-2167700-13E3B387000005DC-955_964x678.jpg

[halfeye]

Fortunately for your nightmares, there's only so big a spider can get. And that means only so big its brain can be, which puts a crimp on the whole intelligence deal. (Also it tends to be the smaller spiders that live socially anyway)

So, it's not the sort of thing that would evolve naturally, so just make up something that fits the world and narrative and use the appropriate local flavour of magic to make it work.
http://en.wikipedia.org/wiki/Coconut_crab

They have an almost working lung, and they are as big as land arthropods get, so far. Improve the lung, and they should go further.

[Tyndmyr]

Full bore nightmare fuel. We don't have a run screaminh from the room smiley, so I will make due with gagging slightly in real life. On the oxygen thing, crusteaceans have fewer size limits and can get much bigger. Make them sea spiders.

Oh yeah, this is like...deepest pits of horror crap here.

To comfort you, I bring you the news that one kind of spider is considered potentially sentient/intelligent, etc. Been a while since I read the release, but they would look at a complex maze(that was not visible when you were in the maze), crane this way and that, memorizing how to get through it to the prize, and then run the whole(insanely complex) thing.

See, the thing is, brains scale in relation to creature size, not merely intelligence. Otherwise, blue whales would be WAY smarter than humans. Absolute brain side doesn't mean much, just relative to the size of the creature. So, really, nothing prevents horrifyingly intelligent spiders.

Which is why the world needs to burn.

[halfeye]

Oh yeah, this is like...deepest pits of horror crap here.

To comfort you, I bring you the news that one kind of spider is considered potentially sentient/intelligent, etc. Been a while since I read the release, but they would look at a complex maze(that was not visible when you were in the maze), crane this way and that, memorizing how to get through it to the prize, and then run the whole(insanely complex) thing.

See, the thing is, brains scale in relation to creature size, not merely intelligence. Otherwise, blue whales would be WAY smarter than humans. Absolute brain side doesn't mean much, just relative to the size of the creature. So, really, nothing prevents horrifyingly intelligent spiders.

Which is why the world needs to burn.
Not true. The thing is intelligence is some sort of function of size, probably excess brain over what's needed for the size of body. If there's enough excess brain, then there might be intelligence. Spiders just can't get big enough to have intelligence, their lungs don't scale up.

We don't know how intelligent whales are, yet.

[GloatingSwine]

See, the thing is, brains scale in relation to creature size, not merely intelligence. Otherwise, blue whales would be WAY smarter than humans. Absolute brain side doesn't mean much, just relative to the size of the creature. So, really, nothing prevents horrifyingly intelligent spiders.


Absolute brain size is still quite important. Number and connectivity of neurons makes a big difference to brain operation. You can teach a few neurons a complicated task (http://www.newscientist.com/article/dn6573-brain-cells-in-a-dish-fly-fighter-plane.html#.VT6jhK1Viko), but that's not the same as general intelligence.

[Sith_Happens]

This is the best thread on the Internet.

[Gritmonger]

Absolute brain size is still quite important. Number and connectivity of neurons makes a big difference to brain operation. You can teach a few neurons a complicated task (http://www.newscientist.com/article/dn6573-brain-cells-in-a-dish-fly-fighter-plane.html#.VT6jhK1Viko), but that's not the same as general intelligence.

Which, I think, is where we get to what comes first - personally, I think that the amount of processing power required to parse complex information (visual or sonar) in three dimensions makes for excess power, overkill if you will. And that overkill (excess processing power) can get turned to other things over time. Like curiosity (leading to new food sources), storing away new behaviors, and so-on.

Complex sensory input parsing leads to more complicated processing which can lead to intelligence.

Mind you, this is a personal view - but I think it holds up pretty well across species. Octopi are smart, but they aren't communal-living, social (as we think of social), and they die before their young are born (or right when) so they can't pass on behaviors.