But it's not just this flexible behavioral repertoire that's so amazing. It's not the fact that somehow, this dumb little spider with its crude compound optics has visual acuity to rival a cat's (even though a cat's got orders of magnitude more neurons in one retina than our spider has in her whole damn head). It's not even the fact that this little beast can figure out a maze which entails recognizing prey, then figuring out an approach path along which that prey is not visible (i.e., the spider can't just keep her eyes on the ball: she has to develop and remember a search image), then follow her best-laid plans by memory including recognizing when she's made a wrong turn and retracing her steps, all the while out of sight of her target. No, the really amazing thing is how she does all this with a measly 600,000 neurons— how she pulls off cognitive feats that would challenge a mammal with seventy million or more.
She does it like a Turing Machine, one laborious step at a time. She does it like a Sinclair ZX-80: running one part of the system then another, because she doesn't have the circuitry to run both at once. She does it all sequentially, by timesharing.
She'll sit there for two fucking hours, just watching. It takes that long to process the image, you see: whereas a cat or a mouse would assimilate the whole hi-res vista in an instant, Portia's poor underpowered graphics driver can only hold a fraction of the scene at any given time. So she scans, back and forth, back and forth, like some kind of hairy multilimbed Cylon centurion, scanning each little segment of the game board in turn. Then, when she synthesizes the relevant aspects of each (God knows how many variables she's juggling, how many pencil sketches get scribbled onto the scratch pad because the jpeg won't fit), she figures out a plan, and puts it into motion: climbing down the branch, falling out of sight of the target, ignoring other branches that would only seem to provide a more direct route to payoff, homing in on that one critical fork in the road that leads back up to satiation. Portia won't be deterred by the fact that she only has a few percent of a real brain: she emulates the brain she needs, a few percent at a time.
As an Aussie I get to see a lot of spiders, and they are absolutely amazing creatures. I can spend ages watching an orb weaver spider carefully constructing its web by ziplining down single threads at a time to get every part of the web to just the right spot in 3D space. They do other amazing things as well: for instance, funnelweb spiders can survive underwater by trapping air around them. (As a result of which we need to check pools very carefully before swimming.) I am thoroughly unsurprised that spiders are as intelligent as the article reports.
I once saw a spider hoist himself up 2 stories in a most elegant way. I was sitting outside on the porch and a gentle breeze was blowing. I noticed this shimmering line floating and it went up until it latched unto the roof and then this little creature just floated up from the porch and a few seconds later, was on the roof. It was almost like a dance. I remember being very impressed with that little spider and admiring it.
I did some amateur research on this years ago. I couldn't understand how a spider can 'fly' with a thread of gossmer, than has no aerodynamic lift. The most likely explantion is that the spider is falling in a rising column of convective air, but (in some cases) the thread allows it to fall slower than the air is rising.
"ballooning mechanisms are not fully explained by current aerodynamic models. The global atmospheric electric circuit and the resulting atmospheric potential gradient (APG) provide an additional force that has been proposed to explain ballooning"
So perhaps a combination of drag and electrostatic force. And, unless the spider can build up a substantial charge on the thread, I am guessing that drag is the more important part.
The surface of spider thread is such that air blowing across it takes away charge, leaving behind the opposite charge.
So, atmospheric drag provides horizontal motion, and electrostatic repulsion provides vertical motion. Once the spider is aloft, air motion relative to it falls off, and the charge begins to leak away. Eventually it descends.
The rising convective air dragging along a vertical thread also provides some lift.
I wonder if anyone has tried to lift a spider using electrostatic forces alone and what voltage that would need? You'd think it wouldn't that hard an experiment to do.
I simply hate them sorry. If they were any larger, they would prey on us in the same way that they prey on their own scale creatures -- and that is simply frightening.
I'm not sure if your second sentence was meant to be the sole justification for the first, but unless you're bothered by other small predators (cats, bullfrogs, mantises, etc) then there's got to be something else behind it.
Well I am bothered by those other predators -- and you have inadvertently proven my point: Large cats such as lions or tigers are fearless predators of people.
But you are right. It's the whole trap your unsuspecting victim in a giant immobalazing web, wrap them up in silk and then :
"As a first step in eating, the spider will literally vomit digestive fluid over the prey. Then the prey is chewed with the "jaws" (chelicerae), and the fluid is sucked back into the mouth together with some liquefied "meat" from the prey"
Yooo, when I was in grade school there was a jumping spider on the monkey-bars so I started throwing bark ships up at it trying to scare it off so I could swing around... The little fucker jumped off the monkey-bars right onto my elbow and bit me.
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[ 0.21 ms ] story [ 66.4 ms ] threadBut it's not just this flexible behavioral repertoire that's so amazing. It's not the fact that somehow, this dumb little spider with its crude compound optics has visual acuity to rival a cat's (even though a cat's got orders of magnitude more neurons in one retina than our spider has in her whole damn head). It's not even the fact that this little beast can figure out a maze which entails recognizing prey, then figuring out an approach path along which that prey is not visible (i.e., the spider can't just keep her eyes on the ball: she has to develop and remember a search image), then follow her best-laid plans by memory including recognizing when she's made a wrong turn and retracing her steps, all the while out of sight of her target. No, the really amazing thing is how she does all this with a measly 600,000 neurons— how she pulls off cognitive feats that would challenge a mammal with seventy million or more.
She does it like a Turing Machine, one laborious step at a time. She does it like a Sinclair ZX-80: running one part of the system then another, because she doesn't have the circuitry to run both at once. She does it all sequentially, by timesharing.
She'll sit there for two fucking hours, just watching. It takes that long to process the image, you see: whereas a cat or a mouse would assimilate the whole hi-res vista in an instant, Portia's poor underpowered graphics driver can only hold a fraction of the scene at any given time. So she scans, back and forth, back and forth, like some kind of hairy multilimbed Cylon centurion, scanning each little segment of the game board in turn. Then, when she synthesizes the relevant aspects of each (God knows how many variables she's juggling, how many pencil sketches get scribbled onto the scratch pad because the jpeg won't fit), she figures out a plan, and puts it into motion: climbing down the branch, falling out of sight of the target, ignoring other branches that would only seem to provide a more direct route to payoff, homing in on that one critical fork in the road that leads back up to satiation. Portia won't be deterred by the fact that she only has a few percent of a real brain: she emulates the brain she needs, a few percent at a time.
https://en.wikipedia.org/wiki/Ballooning_(spider)
"ballooning mechanisms are not fully explained by current aerodynamic models. The global atmospheric electric circuit and the resulting atmospheric potential gradient (APG) provide an additional force that has been proposed to explain ballooning"
So perhaps a combination of drag and electrostatic force. And, unless the spider can build up a substantial charge on the thread, I am guessing that drag is the more important part.
So, atmospheric drag provides horizontal motion, and electrostatic repulsion provides vertical motion. Once the spider is aloft, air motion relative to it falls off, and the charge begins to leak away. Eventually it descends.
I wonder if anyone has tried to lift a spider using electrostatic forces alone and what voltage that would need? You'd think it wouldn't that hard an experiment to do.
We have eons of new technology development ahead of us just figuring out how certain animals function natively.
Like the meta-meta-mercenary who only kills meta-mercenaries who only kill mercenaries.
But you are right. It's the whole trap your unsuspecting victim in a giant immobalazing web, wrap them up in silk and then :
"As a first step in eating, the spider will literally vomit digestive fluid over the prey. Then the prey is chewed with the "jaws" (chelicerae), and the fluid is sucked back into the mouth together with some liquefied "meat" from the prey"
https://www.burkemuseum.org/collections-and-research/biology...
Spiders know what they're doing lol