Thread: the smartest spider ever?!!

I love spiders and think they are some of the coolest, most varied, and the most intelligent of all creatures with an exoskeleton. My favorite one as far as intelligence goes is the trap-door spider. This spider burrows a hole and then drags a rock or similar object over the hole. There they wait until something comes near. Like all spiders, trap-doors have a very keen sense of touch that allows them to feel even the tiniest vibrations. They can then pick out and identify what made those vibrations as far as size, weight distribution, etc. Something walks by its home. The spider recognizes it as an insect of some sort. It creeps up the hole, pushes the rock up, and looks to see what it is. It then pounces, grabs the insect, and drags it into its hole where, unlike other spiders, is eaten on the spot. But where the spider's real intelligence is demonstrated is something like the following scenario; a human walks by accidentally kicking the rock and spraying dirt on the spider. The spider will close its eyes, tense up, and stay still until the vibrations cease. Then it shakes itself off, climbs up, and repairs the damage. This demonstrates a cognitive ability that was never before seen in such a creature. Because of these traits, the trap-door spider is one of the most efficient, successful, and intelligent creatures on the planet.

::


But yeah I dispute this one on a few levels:

the trap-door spider is one of the most efficient, successful, and intelligent creatures on the planet.

Don't mistake predatory instinct for intelligence.

and the most intelligent of all creatures with an exoskeleton

Hard to qualify methinks

But where the spider's real intelligence is demonstrated is something like the following scenario; a human walks by accidentally kicking the rock and spraying dirt on the spider. The spider will close its eyes, tense up, and stay still until the vibrations cease. Then it shakes itself off, climbs up, and repairs the damage. This demonstrates a cognitive ability that was never before seen in such a creature.

See first point. Seriously.

It then pounces, grabs the insect, and drags it into its hole where, unlike other spiders, is eaten on the spot

Untrue. Some spider courtship involves giving a gift of a 'ready to eat' insect; certainly not one that was eaten on the spot. Just an example for you

Is this a discussion thread or were you just wanting us all to know how cool you think trapdoor spiders are? Your description, save the burrowing part, could be a myriad of other spiders.


Edit:
Anyone else notice this:

Joined: 05 Jan 2009
Posts: 84

insane, even worse than me

Originally Posted by the man of science

The spider will close its eyes

Spiders have eyelids?

The trapdoor spider follows a specialized routine. It's more like a robot performing operations in sequence. Yes it has some very acute senses and great processing power, but that isn't intelligence. It never actually learned what different vibrations mean. It just knows.

Personally I feel the roaming species must be more intelligent, because every situation to them is novel.

Spiders do in fact have eyelids that are similar to a nictating membrane. If they didn't eye damage could occur. I know about the ready to eat gift, but that is still an example of saving the food for later. Every spider besides the trapdoor spider saves their catches to be eaten at a later time. I believe it is intelligence and not just predatory instinct. Younger trapdoors are often eaten or killed due to misinterpretations of vibrations or poor burrow covering. Also trapdoors learn based from mistakes, which is not an instinctual ability at all.

Man of science - you're a troll.

I find it interesting that the young of some species stay in their mother's burrow until they are nearly adults, which is two to three years. This would most certainly represent an opportunity for learning. Unfortunately I couldn't get full access to the paper I was reading so I don't know if any more research has been done in that direction.

http://icb.oxfordjournals.org/cgi/co...stract/9/1/175

Certainly not all trapdoor spiders use web lines. Amongst Australian species, only those living in drier habitats use them, presumably to increase their hunting area as prey is in general more scarce.

http://www.publish.csiro.au/?paper=ZO9570402
(I have the full text of this one if anyone is interested.)

There appear to be trapdoor spiders in many tropical areas in the world. It would be interesting to find a phylogenetic analysis of all these groups. I wonder if some arose independently.

Why I am a troll? Man there are haters everywhere.

Originally Posted by the man of science

Why I am a troll? Man there are haters everywhere.

You are a troll because you know damn well spiders do not have eyelids. You are coming here saying outrageous stuff just to get a rise out of people and watch them sincerely trying to correct the silly stuff you say.

Well srry can't a guy have a little fun? From now on I'll stick to straight facts. When spiders get something in their eyes its pretty bad news. They gently remove the stuff on their eyes with their 2 front feelers that they use as hands. They use those 2 front feelers to act as eyelids and they will cover their eyes with them when they sleep.

Originally Posted by Harold14370

Originally Posted by the man of science

Why I am a troll? Man there are haters everywhere.

You are a troll because you know damn well spiders do not have eyelids. You are coming here saying outrageous stuff just to get a rise out of people and watch them sincerely trying to correct the silly stuff you say.

not to mention his postcount is off the charts since he joined 5 days ago.


Harold you are officially in my cool books.

My post count is off the charts because I know tons of stuff and want to learn as well.

Originally Posted by the man of science

My post count is off the charts because I know tons of stuff and want to learn as well.

I'm looking forward to the point when you start contributing it. 8)

dude thats not cool. In case u haven't noticed I have contributed alot and most of it has been correct.

Originally Posted by John Galt

Originally Posted by the man of science

My post count is off the charts because I know tons of stuff and want to learn as well.

I'm looking forward to the point when you start contributing it. 8)

Why is this thread getting better with every post?

dude thats not cool. In case u haven't noticed I have contributed alot and most of it has been correct.

Not in this thread you haven't...and why do you post shit you know isn't correct?

everything up until the eyelids joke was 100% correct.

Originally Posted by the man of science

everything up until the eyelids joke was 100% correct.

Not so. As mormoopid pointed out you likely overstated the case for intelligence on the part of the trapdoor spider.

I seem to have been interacting rather a lot with you over the last few days. In nearly every instance you have wound up accepting a correction, or going off at a tangent.

Great enthusiam. I don't want to put a damper on it. But enthusiasm can be most effective when it is controlled and directed. You might want to give that some thought. Why not try using fewer absolutes in your posts? And why not spend some of the time checking your facts before you post? Just some well intentioned thoughts.

Only once or twice was I wrong and at that time I accepted it. I am not overstating its intelligence at all.

Originally Posted by the man of science

Only once or twice was I wrong and at that time I accepted it. I am not overstating its intelligence at all.

I'm not wishing to get into a shouting match, but you might wish to review the threads and reconsider the statement in your first sentence. I think you'll find it is incorrect.

As far as the intelligence of the spider is concerned you are expressing an opinion. Its intelligence is not an established fact. Its behaviour is likely instinctive. If you contend otherwise please provide some documentary evidence, ideally citations from peer reviewed journals, to justify your claim.

Any further off-topic content in this thread will be removed. If some of you have concerns over another poster's posting quality, deal with it via PM. If you think there's a troll around, PM me.

man of science, I am unhappy to hear that you gave misinformation as though it was fact. There is technically no rule against this but it most certainly does not foster scientific discussion, no matter if your intentions were joking (though I personally don't see what's so funny about it). I am asking that you please refrain from this in the future.

/moderator mode

Off-topic content removed.

If you have requests of me as a moderator, do it via PM, not in a thread.

Paralith

Back on topic.

The most intelligent spider is the jumping spider.

Why?
1. They are hunters who are have to actually reason out tactics to sieze their prey, everytime different with new challenges
2. jumping spiders are the only spider with very good eyesight (about as good as a dog's actually!). Web spiders have very poor eyesight. I don't know about trapdoor spiders.
3. jumping spiders (species portia labiata) have been tested in complex mazes and they can outperform rats. Only primates outperform jumping spiders in mazes.

I have several posts on this subject in a thread on this subject a month ago in the Animals forums of the space.com forums, you can find links to journal papers there. http://www.space.com/common/communit...life.space.com

dog's have pretty poor eyesight.

Would it be unfair to say that an animal's intelligence is dependent on its brain:body size ratio and the overall size of its brain? And that intelligence is proportional to a combination of these two factors? Maybe I'm confusing intelligence for knowledge capacity or something of that kind, but it seems to be the trend that the animals with the largest brains for their body (Humans, I think) are considered the most intelligent.

Jumping spiders have a huge brain/size ratio, judging from the figure (I dont have weights), much greater than humans. Please see the link I posted in the earlier thread, and read it. It has this information too.

Of course the absolute size of the brain is important too.

Originally Posted by spuriousmonkey

dog's have pretty poor eyesight.

Actually dogs have pretty good eyesight. I don't know where you got your information from.

Dogs see in two colors (not three major ones like primates). Dogs have a tapetum lucidum, which effectively doubles their photon capture effieciency compared to apes, making their night sight twice as good as ours.

In humans, flicker fusion occurs at about 50 Hz (ability to differentiate flickering lights). Dogs can discern flicker at 70 Hz or greater, giving them a better flicker detection than humans. Fluorescent light must drive them crazy! This is useful, for a study indicated that dogs could discriminate an object in motion at 810 to 900 meters, but were only able to discriminate the same object when stationary at 585 meters or less.

Humans have about a 180 degree of view, dogs have a wider field of view, 240 degrees. Dog's binoculor overlap is about 40 - 60 degrees, compared to about 140 degrees in humans, so less of their visual field is in 3D.

Dog's visual acuity is approximately 20/75. This is better than perhaps 1/4 of the population of the US, judged by uncorrected visual acuity.
http://psychlops.psy.uconn.edu/eric/...dogvision.html

There is a general trend in mammals for increasing brain size to body size ratio to relate to increased intelligence between species. The exact mechanisms behind this trend are unknown, and there are a variety of ways in which this ratio can be measured.

I do not know if there is a similar trend in other animals, let alone invertebrates like spiders. Their brains are fundamentally different in structure from those of mammals so a direct comparison probably cannot be made at the current state of knowledge.

Originally Posted by silylene

Dogs can discern flicker at 70 Hz or greater, giving them a better flicker detection than humans.

I may be misunderstanding this, but does this mean that computer screens will flicker in dogs' eyes? Do they find this annoying? I have never seen a dog and a computer screen in the same place, so I wouldn't know.

It has a very small brain size, the new scientist article actually does go on to explain how the unique nature of the spider's eyes could result in a sort of selective blindness and serial memory, that functions instinctively but seems to mimic intelligence because of how efficient it is. It's certainly interesting, but the way this spider behaves can not really be compared to intelligence of mammals.

Smartest spider on the other hand, maybe? Arthropods in general are usually thought of as being completely dependent on instinctive behavior.

Originally Posted by paralith

There is a general trend in mammals for increasing brain size to body size ratio to relate to increased intelligence between species. The exact mechanisms behind this trend are unknown, and there are a variety of ways in which this ratio can be measured.

I do not know if there is a similar trend in other animals, let alone invertebrates like spiders. Their brains are fundamentally different in structure from those of mammals so a direct comparison probably cannot be made at the current state of knowledge.

paralith is right in the first paragraph.

The further you move from mammalia, the harder it is to accurately measure intelligence (especially what we consider intelligence) because the comparison becomes more and more vague. And what do you know, she's right in the second paragraph too!

True that the brains of spiders and vertebrates are organized very differently, and I have no idea how this impacts on intelligence. My point was simply that the jumping spider has a very large brain / body size ratio, and bigger than most mammals.

Absolute brain size is also a very important factor. A tiny brain will simply lack enough neurons and connections to be capable of significant reasoning ability.

All that said, jumping spiders abilities in 3-dimensional maze navigation significantly exceed the abilities of most mammals (see my link in the prior post please). This does takes short term memory, mental mapping, and reasoning ability, and maze navigation is not a 'pre-programmed' ability.

Originally Posted by Hazz

Originally Posted by silylene

Dogs can discern flicker at 70 Hz or greater, giving them a better flicker detection than humans.

I may be misunderstanding this, but does this mean that computer screens will flicker in dogs' eyes? Do they find this annoying? I have never seen a dog and a computer screen in the same place, so I wouldn't know.

Maybe dogs find some computer screens annoying from flickering. I personally find most cheaper cathode ray tube monitors annoying and exhausting because I can see the 60 Hz flickering in my non-fovea vision. Only the high-end CRTs with good video cards have 75 Hz and better capability, which has a lot less eye fatigue for me at least. (At work we had to endure for decades cheap CRTs and no monitors!)

LCD screens are much better, as I see no flicker at all.

As far as dogs are concerned, I would guess that perhaps the disinterest most dogs have in watching television has to do with their ability to discern the annoying flicker in TVs (in the US analog TV is 60 Hz, but only 30 interlaced frames/sec).

Originally Posted by silylene

True that the brains of spiders and vertebrates are organized very differently, and I have no idea how this impacts on intelligence. My point was simply that the jumping spider has a very large brain / body size ratio, and bigger than most mammals.

And no one was arguing with the truth of your statement. We were arguing its relevancy when comparing intelligence between vastly different classes of organisms.

Absolute brain size is also a very important factor. A tiny brain will simply lack enough neurons and connections to be capable of significant reasoning ability.

All that said, jumping spiders abilities in 3-dimensional maze navigation significantly exceed the abilities of most mammals (see my link in the prior post please). This does takes short term memory, mental mapping, and reasoning ability, and maze navigation is not a 'pre-programmed' ability.

Though I admit I don't know a whole lot of neuroscience, it's my feeling that structural/organizational differences in brains my one day be shown to have almost as significant an effect on brain function as size, be it relative or absolute. I don't think this means that a brain the size of a jumping spider's will be able to equal the cognitive ability of a human, but it could most certainly enable it to have greater cognitive ability than we would expect of a brain that size organized in a mammalian fashion.

You also have to consider, however, exactly what you mean when you speak of the reasoning ability of a jumping spider. I read your articles, and I found it very interesting how the spider studied would sit and stare at a scene for hours plotting its path through the environment to the prey. Clearly what it has over other spiders in terms of analysis it loses in speed. In the niche that this spider occupies, clearly this time lag is not a survival problem - but it most definitely would be in many other species. Processing speed is, at least in my estimation, an important part of overall intelligence.

A mouse might not be able to solve the maze the first and at least the second time it tries it, but I wouldn't be surprised if a mouse's active search method would allow it to understand a maze of relatively equal size to that presented to the spider in a nearly equal amount of time.

I also found it interesting how your article also provided an explanation for how at least some of this spider's remarkable abilities may in fact still be instinctive:

Harland thinks that understanding the serial nature of the spider's vision makes it easier to imagine how prey recognition and other processes could be controlled by hard-wired programs. When Portia is looking for an egg sac, for example, it wouldn't need to deal with the scene as a visual whole. Instead it could check a template, ticking off critical features in a sequence of fixations. Perhaps the less the eye sees with each fixation the better.

The human brain, on the other hand, has to cope with a flood of information, and much of the work lies in deciding what to ignore. The laser-like focus of Portia's eyes might do much of this filtering by default. So what seems like intelligent decision-making could really be an evolved selective blindness.

This does not explain everything this spider does of course, but it certainly provides an example of how basic differences in the way information is processed can lead to an instinctive behavior that appears to imitate the flexibility displayed by other animals.

Originally Posted by paralith

Though I admit I don't know a whole lot of neuroscience, it's my feeling that structural/organizational differences in brains my one day be shown to have almost as significant an effect on brain function as size, be it relative or absolute. I don't think this means that a brain the size of a jumping spider's will be able to equal the cognitive ability of a human, but it could most certainly enable it to have greater cognitive ability than we would expect of a brain that size organized in a mammalian fashion.

You also have to consider, however, exactly what you mean when you speak of the reasoning ability of a jumping spider. I read your articles, and I found it very interesting how the spider studied would sit and stare at a scene for hours plotting its path through the environment to the prey. Clearly what it has over other spiders in terms of analysis it loses in speed. In the niche that this spider occupies, clearly this time lag is not a survival problem - but it most definitely would be in many other species. Processing speed is, at least in my estimation, an important part of overall intelligence.

I am also not disagreeing with anything you said. I actually find this study of spider intelligence to be fascinating (as you pointed out in some of the details), as it gives us an insight in a very non-mammalian brain that has evolved very differently from ours.

Please see the part of your statement I outlined in red. Clearly a small brain can still be quite unexpectedly smart. For example, the Caledonian Crow has a tiny brain compared to a primate. Yet it can fashion its own tools from either the serrated palm leaves it finds in the jungle, or from never encountered before wires in a laboratory, to solve the problem on how to get food better than even a chimp is capable of doing. Another example is H. Flores, which has a brain not much bigger than a chimp. Yet this cousin of man was apparently able to fashion stone spearheads, spears and make fires. I think both of these cases speak to the value of brain organization.

On the opposite (in a way), a large brain can make one smart, even if the brain/body ratio is not within the primate category...for example the elephant. They are one of the few animals which can self-recognize in a mirror, have a long childhood of learning like humans, with training they can construct and paint recognizable 2D figures as well as many humans, and they possess a basic communication language.

wire: http://news.nationalgeographic.com/n...0808_crow.html
there's a fascinating youtube video of this somewhere I recall watching

elephant painting: http://www.snopes.com/photos/animals...ntpainting.asp

For what its worth, I once saved a jumping (or wolf, not sure of the difference) spider from the web of some other spider; for the rest of that season my "little friend" would come out of his hiding space when I was near and just watch me. Sometimes I would put my hand down and he or she would climb on, hang out for a little while then jump off. I know it was the same spider because he was missing one leg. Not sure if it indicates intelligence, but the little guy or girl seemed to know who I was and that I was not a threat.

Originally Posted by todd tomorrow

For what its worth, I once saved a jumping (or wolf, not sure of the difference) spider from the web of some other spider; for the rest of that season my "little friend" would come out of his hiding space when I was near and just watch me. Sometimes I would put my hand down and he or she would climb on, hang out for a little while then jump off. I know it was the same spider because he was missing one leg. Not sure if it indicates intelligence, but the little guy or girl seemed to know who I was and that I was not a threat.

I stayed at a hotel that had a small resident spider in the bathroom, tending it's small web, tucked into an obscure location where room service would not easily find it, lol. I have a fairly benign attitude toward spiders of most kinds as they generally are a beneficial species in this climate. We declared a truce and the spider and I went about our respective business without alarm for the duration of my stay.

I remember in the movie Charlotte's Web that the spider was very smart, even spelling out what she was after for breakfast!

Originally Posted by cosmictraveler

I remember in the movie Charlotte's Web that the spider was very smart, even spelling out what she was after for breakfast!

I sense MacGyver's influence in this. I cohabit with plenty of spiders and none of them have ever demonstrated any interest in bacon, raw or cooked.

I do not believe that there is any significance to brain / body size percentage other than what ends of being matter of fact. This is due to the required brain size against an ultimate bottom limit of necessary neurons for the the animals requirements.

Fire and pharaoh ants are truly tiny. Their physical bodies fit well within the niche that they have evolved in. Their brains are large compared to their bodies because a smaller number of neurons simply won't get the job done.

A good example is that of my favorite animal, the jumping spider. At 1/4" long, a species may have its cephalothorax stuffed to 35% capacity with brain.

Larger jumping spiders don't necessarily have larger brains. Larger jumping spiders have smaller brain/body percentages. Once the required amount of neurons are available for the animals needs, it's not necessary for the brain to be much larger. Jumping spiders of varying sizes can have brains of equal size, and both be just as intelligent.

I'm 5'10", 200 lbs. My brain/body percentage is lower than that of someone born a dwarf, or someone who is genetically a true pygmy. I would not expect these ratios to have any bearing on actual intelligence, other than my not being smart enough to get off my butt and exercise more.

The measuring stick for basic species intelligence is absolute brain size, not its relation to the size of the rest of the body.

So the real question is why do jumping spiders have such a neuron requirement? Why won't a smaller brain do the job? What do they need smarts for?

I've had numerous jumping spider pets, and I know that they can learn by trial and error. They have to be able to learn, because while genetics can predispose them to try a fulcrum drag-line jump to a surface they can't jump to directly, they don't always get it correct without practice.

I've seen them examine a jump, change position, look again, go back to the first position, look, consider, ponder, pontificate, day dream, waste time, wonder when the next episode of Dexter will finally air, and finally jump and miss. Then they climb up and try again from another launch point until they get the goodie (a semi-live fly pinned to a dowel).

Can they reason? I'm really not sure what actually constitutes reasoning ability in a spider. I haven't thought up a test for it. I've seen reasoning demonstrated in a cricket, but not a jumping spider yet.

I know that they think slowly. For something that moves in such quick, staccato movements, it's surprising how patient they can be at figuring out a jump path.

They don't have an innate fear of people, as other spiders do. They will readily jump onto your finger, and as long as you keep offering them another finger higher than the one they are on, they will continue to jump up to the next and the next. I don't consider this innately smart behavior. Humans are great and terrible destroyers of small many-legged critters. Jumping spiders seem to have a child-like ignorance of greater predators.

I believe they are capable problem solvers. They have to be, because the are not trappers. I think only one known type waits for prey to come to them. The rest are mobile hunters looking for mobile prey.

I tend to be polite to frogs, spiders, snakes, and wasps they all eat things I don't want to share my space with.

My son the science teacher said that our wolf spiders who wander about are males, and those with the funnel shaped webs are females.
We also used to have large yellow and black "garden spiders" but I ain't seen any this year(so far).

Mr Ekshin

Welcome to the forum. There are some Dexter topics in this forum I think, or maybe it was the other forum. Anyway you can't be all bad if you like Dexter.


The following is a short video from the TV series "Monster Bug Wars" featuring the green jumping spider. Very impressive little bugger.

bug wars - Bing Videos

At first I thought I'd never heard of the "Ogre-faced spider", but once I saw it's "net", I

realized that I had seen that some time in my dim past.


I had no idea that their night vision was so good. I wonder how people test for that?


"OK... what's our distance for this test?"

"We have... 12 meters. I mean 11. No wait, 12. Definitely 12."

"All set then, and hold up the banana... now!"

"Got it. Banana is a go."

"Is it looking?"

"I... I think so. It looked our way, yes?"

"I can't really tell, I swear it's hard to see from here. I keep losing him."

"What?"

"Well, it IS dark. He may have great night vision, but I can't see for beans out here."

"His net twitched! It definitely... no that's a leaf."

"okay..."

"Right."



"Are we sure they even like bananas?"

_____

Anywho...

Dr. Linda S. Rayor from that video said (twice) "posterior median eyes". No, those two big

headlights are the anterior (front) median eyes. No soup for her!

Then again, she really gets an "A" for her enthusiasm. She was positively giddy about that spider.

Originally Posted by Mr Ekshin

I had no idea that their night vision was so good. I wonder how people test for that?

In the lab they can put an insect or spider eye under a microscope and simply count the receptors (rods and cones) More rods means better night vision and more cones is better color vision in daylight. With animals that have good night vision, not only do they have a higher rod density, they have eye shine. This is a coating that reflects the light of the few meager photons from behind the retina back to the rods. In a sense it's a way to double the amount of available light. I don't think bugs have eye shine but they could have a very high rod density per a given area on the retina.