# How bright are spiders? **URL:** \ **Category:** Factual Questions\ **Created:** [January 8, 2006, 3:35am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967 "2006-01-08T03:35:38Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\ **Post date:** [January 8, 2006, 3:35am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/1 "2006-01-08T03:35:38Z")
I read recently in a fascinating little book called, I believe, Mini-Monsters, that some species of spiders have shown to have rudimentary problem-solving skills. Is this true? ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [January 8, 2006, 3:56am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/2 "2006-01-08T03:56:12Z")
_makes obligatory radioactive spider joke_ ---
**Author:** ![MC\_E](https://avatars.discourse-cdn.com/v4/letter/m/c77e96/32.png) [@MC\_E](https://boards.straightdope.com/u/MC_E)\ **Post date:** [January 8, 2006, 5:05am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/3 "2006-01-08T05:05:50Z")
We’ve had spiders smart enough to hide on the little black tiles of our black and white tile floor, after you take a swat at them. It makes them very hard to see. I don’t know about problem solving though… ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [January 8, 2006, 6:00am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/4 "2006-01-08T06:00:37Z")
> [@Love Rhombus](#): > > I read recently in a fascinating little book called, I believe, Mini-Monsters, that some species of spiders have shown to have rudimentary problem-solving skills. Is this true? I’d have to question that; spiders are extraordinarily well adapted, but their responses seem to be pretty much autonomic. Spiders don’t really have brains in the geniune sense of the word; they have two nerve ganglia–roughly corresponding to the two brain hemispheres in other phylia–that provide impulse response but can scarcely be compared to brains in even the dumbest vertebrates or mollusca. They do display learning ability via aversion behavior, but so do flatworms. Conceptual problem solving ability (i.e. the ability to idealize a situation and calculate an optimal approach) is well and beyond any reasonable expectation of their abilities. Spiders are very cool biomechanical machines, and I love watching them at work, but they aren’t going to be winning any Nobel Prizes, or even bumping the curve on the SAT. Stranger ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [January 8, 2006, 6:21am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/5 "2006-01-08T06:21:37Z")
Yes, some spiders are extraordinarily smart. I recall reading a science magazine article (probably _Discover_) about a certain species of spider which preys on other spiders. It would imitate the mating behaviour of the other spider to lure it out into the open where it was vulnerable to attack. Apparently it was able to learn and remember mating behaviours of species it had never before encountered. Perhaps some resident arachnologist will know which spider I’m talking about and provide its full name. ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [January 8, 2006, 6:25am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/6 "2006-01-08T06:25:22Z")
> [@psychonaut](#): > > Apparently it was able to learn and remember mating behaviours of species it had never before encountered. I should add that I don’t remember whether the spider learned from trial and error or from watching authentic matings. But in either case it’s impressive that it would remember the mating behaviour and subsequently use it to capture prey. Some of the behaviour learned was pretty complex, as I remember… it can range from plucking web strings in a certain pattern to dancing to waving its arms in a certain way to combinations of these. Sorry for the lack of a precise cite, but as I said, the magazine was most likely an issue of _Discover_ between 1997 and 1999. ---
**Author:** ![chinaglenn](https://avatars.discourse-cdn.com/v4/letter/c/e5b9ba/32.png) [@chinaglenn](https://boards.straightdope.com/u/chinaglenn)\ **Post date:** [January 8, 2006, 6:52am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/7 "2006-01-08T06:52:22Z")
The spider is of course famous for making sticky spider webs to catch flies and other bugs for food. These webs are very ellaborate and it is interesting to watch a spider making these creations. This is called INSTINCT. The spider knows how to make a web, it does not have to think about it. I doubt that spiders have any real analytical reasoning, but I have been a dick and set flame to a web and the spider knows to run away from the fire. If you don’t kill the spider (spiders are good creatures that keep the flies and skeeters at bay), the spider will just say “$HIt!” in Spiderese and just go to make another web. it has no choice in the matter, Instinct again. When I was younger, I was homeless for a short time in San Francisco. I hung out with the bums and winos from Height Ashbury and one young yet truly alcoholic fellow did something he called “Spidering” which was to pick up a discared drink (mostly beer bottles left outside by clubbers) and consume the contents. Yum! ---
**Author:** ![TellMeI\_mNotCrazy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tellmei_mnotcrazy/32/3419_2.png) [@TellMeI\_mNotCrazy](https://boards.straightdope.com/u/TellMeI_mNotCrazy)\ **Post date:** [January 8, 2006, 10:21am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/8 "2006-01-08T10:21:58Z")
I remember seeing something on Discovery, I think it was, where they had a contraption set up to test the “thinking” ability of spiders. It basically looked like a large tuning fork elevated off the floor. At the end of one tine, they placed a fly, and nothing on the other tine. The spider was placed at the beginning of the “handle” and observed to see if it would work out the best way to get to the fly. And it did, repeatedly, take the correct path to get to the fly. Sounds sort of basic, I guess, but it’s pretty impressive considering that upon reaching the handle, the spider had to work out whether it should go left or right to get to a fly that was vaguely in front of him. ---
**Author:** ![don\_t\_ask](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@don\_t\_ask](https://boards.straightdope.com/u/don_t_ask)\ **Post date:** [January 8, 2006, 10:27am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/9 "2006-01-08T10:27:13Z")
I remember when I was a kid I asked my father, “How do spiders know to make webs around electric lights to catch moths when they don’t know what electric lights are?” Never did get an answer. ---
**Author:** ![TellMeI\_mNotCrazy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tellmei_mnotcrazy/32/3419_2.png) [@TellMeI\_mNotCrazy](https://boards.straightdope.com/u/TellMeI_mNotCrazy)\ **Post date:** [January 8, 2006, 10:31am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/10 "2006-01-08T10:31:20Z")
Found a little bit of info on the Portia, which is supposedly one of the best problem-solving spider around: [http://www.ingentaconnect.com/content/brill/beh/2001/00000138/00000010/art00002](http://www.ingentaconnect.com/content/brill/beh/2001/00000138/00000010/art00002) > [@](#): > > Portia is a genus of web-invading araneophagic jumping spiders known from earlier studies to derive aggressive-mimicry signals by using a generate-and-test algorithm (trial-and-error tactic). Here P. fimbriata’s use of trial-and-error to solve a confinement problem (how to escape from an island surrounded by water) is investigated. Spiders choose between two potential escape tactics (leap or swim), one of which will fail (bring spider no closer to edge of tray) and the other of which will partially succeed (bring spider closer to edge of tray). The particular choice that will partially succeed is unknown to the spider. Using trial-anderror, P.fimbriata solves the confinement problem both when correct choices are rewarded (i.e. when the spider is moved closer to edge of tray) and when incorrect choices are punished (i.e. when the spider gets no closer to edge of tray). From [http://www.amonline.net.au/factsheets/portia.htm:](http://www.amonline.net.au/factsheets/portia.htm:) > [@](#): > > Fringed Jumping Spiders use their behavioural skills to lull victims into a false sense of security. Other jumping spiders seem to be taken in by Portia’s slow gait and resemblance to a piece of detritus, allowing it to move fatally close. When invading webs, Portia uses its legs and palps to vibrate the silk in specialised patterns. This may simulate struggling prey or a male spider’s mating signals, causing the web’s unsuspecting owner to move toward the waiting, or slowly stalking, predator. When the victim is about 5 mm away, Portia suddenly attacks, lunging forward, fangs outstretched to grasp its prey and inject a fast acting venom. > > Persistence characterises Portia’s hunting strategy. One spider performed vibratory behaviour in a web for 3 days before the host spider finally decided to investigate and fell victim to it. In another instance, when a direct web approach to an orb web spider was unsuccessful, Portia left the web only to re-appear in the foliage above it. From there the hunter lowered itself down on a silk line beside the web until it was close enough to grasp its victim and deliver a fatal bite. > > How does this species determine which method of attack or web signal to use with a particular spider? Probably, it is through a sophisticated trial and error procedure, backed up by cues from the victim or its web. Portia’s web signalling behaviour seem to be constantly varied until the confused victim finally responds - usually with fatal results. All of this reveals a form of problem solving capacity unmatched by other spiders. ---
**Author:** ![TellMeI\_mNotCrazy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tellmei_mnotcrazy/32/3419_2.png) [@TellMeI\_mNotCrazy](https://boards.straightdope.com/u/TellMeI_mNotCrazy)\ **Post date:** [January 8, 2006, 10:33am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/11 "2006-01-08T10:33:17Z")
Sorry, included a colon in my second link: [http://www.amonline.net.au/factsheets/portia.htm](http://www.amonline.net.au/factsheets/portia.htm) ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [January 8, 2006, 11:26am UTC](https://boards.straightdope.com/t/how-bright-are-spiders/338967/12 "2006-01-08T11:26:04Z")
> [@TellMeI'mNotCrazy](#): > > Found a little bit of info on the Portia, which is supposedly one of the best problem-solving spider around: Now that seeing the name has refreshed my memory, I can confirm that Portia is the spider I was talking about in my previous posts.