With the fall weather, my house has been infested with those nasty, evil spiders that can run like the wind, covering about 20 times their body length in a second. While trying to hunt down and smash the little bastards I started wondering if a person (in relation to their size) could move as quickly, how fast would they be running?
Well, that’s an easy question (especially when Google will do unit conversions between fps and mph). Assuming a 6 foot person, that is 120 fps, and Google tells me that that is 81.8 mph.
Clearly we’ll have to refer to the work of Professors Lee and Ditko, et al.
Assuming they are not carrying coconuts.
Do they have a shrubbery?
There might be a problem decelerating in time to avoid running into the fridge.
That’s why we need a person with the speed of a cockroach - they can run under it.
That depends on how you define “relative to their size”. Why is body length the relevant factor, rather than, say, mass? For that matter, why would one expect speed to scale with size at all?
Supposin’ it has a little blue Dune Buggy?
I wouldn’t expect it to. And I suppose one could calculate it many ways but body length was just what sprang to mind while I was trying not to scream and run away like a frightened little girl…
The top speed of a giant house spider Tegenaria gigantea (whcih could very well be the spider you saw if you live in the Puget Sound area) is 33 body lengths per second (when being chased). So 20 per second would be well within range. Body lengths per second actually is the standard for measuring spider speeds, which depend more on leg length then on the tiny amount of mass involved. If you take a human’s body length as the human’s height (say, 2 meters for a tall man), 33 times would be 66 meters (216.5 feet) per second. However, this is not a very good comparison because humans, unlike spiders, stand erect. A more apt comparison would be the area of ground you cover when striding. This would be less than 1 meter (maybe a full meter when running) so you would actually have to cut the comparative human speed in half to be completely fair. That would be 33 meters per second, which is still 3.5 times as fast as the current world record speed for the 60 meter dash.
Another interesting question: why do you hate harmless house spiders, and go to all that trouble to seek and destroy them? They are beneficial, after all. They are always in the house no matter what you do, and the ones you see are only the tip of the iceberg anyway. So just what do you think you’re accomplishing there, other than lowering your karma? 
Gaaaaaaaaaaaaa!! I hate hate hate them! And I don’t seek them out - it’s when they venture into the open that they sign their death warrant. I know it’s an irrational fear - I can’t even watch them on TV. And thankyoueversomuch for telling me it’s just the tip of the iceberg! Karma be damned - the exterminator came today and sprayed the entire 2000+ sq. ft. house (plus the cellar and attic). I just moved in so there’s no furniture yet and I’ll be damned if I’m going to sleep on my inflatable bed and let the evil bastards run all over me. The last one I smashed on Friday was so huge that even the dog was afraid. And I’ve made huge steps just being able to smash them with a shoe - before I had to drop a phone book on them…
- harmless house spiders are fine.
- Not all house spiders are harmless. Brown Recluses, Hobos, Black widows…a bite from any of these will give you a bad week.
- Not being an expert, I cannot discern a Hobo from a Funnel web spider so, the simple and safe solution - Spidey, meet the business end of a my Swiffer.
I didn’t evolve a feeling of “the willies” whenever a spider crawls across me for no reason. Clearly I’m evolutionarilly meant to squish them by reflex.
Dude! Do you, like, live in my head or something? FWIW that song has done more to help me consider spideys as misunderstood, fun-loving critters than years of self-disciplined urging that they are merely not the fell beasts of the bug world. " GO GO GO!!! "
Having grown up in Seattle and routinely finding S.O.U.S.'s in my bed, in my shoes, in my freaking gloves(holymarymotherofgawd!), I still stand fast in the “Spiders are Ilwrath” camp. In Denver we have black widows (never saw any in Washington), which are startling in the same way as coming home and seeing Ted Bundy in the Lay-Z-Boy watching TV, but they don’t come close to inspiring raw, visceral terror the way Tegenaria gigantea does. And to think of a 6 foot-tall (at the shoulders) house spider chubbing along at 60+ mph quite frankly makes my spine want to leap out of my body through my chest and wrap itself around my head.
I have a list of acceptable places that I can move to, and I’m saddened and depressed that that list is shrinking all the time. I thought the PNW might be on it, but not on your life. As long as you people commonly refer to them as “gigantic house spiders,” I’ll be staying away, thanks.
Clearly, I proscribe to the “Kill it! Kill it with fire!” school of thought.
As much as I dislike winter, I do appreciate how it keeps the bugs small 'round these parts. (Yes, I know about wolf spiders. These do not make any appearances in my home.)
If the exterminator doesn’t work, I’m seriously considering investing in a flame-thrower. Just because I live in a 260 year old wood house is not going to deter me. That’s what insurance in for.
You don’t need to be an expert to know what part of the country you live in. Hobo spiders and brown recluses both have a quite limited distribution. See my pages:
If you’re outside their range, you don’t have them, despite all your ignorant friends who think they know someone who was bitten by one. Even within their range, there are many places where these species are vanishingly rare (for example, I haven’t seen a real hobo spider from Seattle all year). Black widows (real ones) don’t turn up indoors that often, though the false black widow is a common house spider.
In any case, real spider bites (the “I didn’t see what bit me so it was a spider” type don’t count!) are quite rare events, and spiders that happen to be toxic to humans are not any more likely to bite on that account. The danger to humans from spiders is so tiny there is no way that it justifies all the fear and loathing (which is not instinctive, BTW – the smaller the kid, the less likely to be fearful – it’s learned!).
Don’t care. It’s not that I don’t like them because of a fear of getting bitten, I don’t like them because of the question in the OP. They sit there all still and unassuming and then suddenly RUN AT YOU. It could crawl up my arm before I could react enough to get it off! No thank you. If they stay in the walls or outside, I have no problem with 'em, but if they come into my space they’re meeting the wrong end of a flyswatter.
On reading your links, arachnologus, (great username combo) I’m disappointed to learn that I probably wasn’t bitten by a Brown Recluse when I was ten, despite what the doctors told me. Something did give me a lesion the size of a softball, though.
Spiders are cool.