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Over the course of your life time, the average person eats X spider/insects/whatever whilst they are sleeping.

X tends to vary according to who you ask. Is this just an urban legend?

George Chalhoub
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MSpeed
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    Zero is a number... – fred Apr 08 '11 at 13:25
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    A spider scientist once told me that there is [almost] always a spider within 8 feet of you. – JD Isaacks Apr 08 '11 at 17:31
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    @John: Or was it that there is always a spider with all 8 feet in you? – Potatoswatter Apr 08 '11 at 19:10
  • How would a researcher garner this data? If the question is 'how many spiders have I unknowingly swallowed in my life' how can we know? How do we estimate the average occurrence of an event people can't report to a survey instrument? – justin cress Apr 09 '11 at 05:50
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    If you rephrased your question to: How many bug parts (which may include spider body parts) does the average American eat per unit time? That would be quite high since they (bug parts, that is) are 'sprinkled' among the bags of choco-riffic cookies and cake mixes, etc., to name only a few, that Americans eat. Cornell Uni. has a food science dept. and I believe every year they come out with numbers for how many insect and rodent 'bits' are in certain foods. The redeeming fact here is that 'most' of the bug parts are cooked well and do not pose a problem. But eating spiders while you –  Apr 09 '11 at 02:30
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    I liked the old Dave Barry bit, which was to point out that the 8 spiders a year was an average, and because nobody he knew ate any spiders, it must mean that someone, possibly Donald Trump, was eating millions of spiders to get the average up. – Scott Hamilton Apr 12 '11 at 16:14
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    What happens if you eat one while awake, and then it crawls out of you...? Is that eating `-1` insects while sleeping? – Mateen Ulhaq May 12 '11 at 00:31
  • @billynomates The answer you have accepted is not correct. I'd suggest you have a look at the comments on the answer and the related question on the Lisa Holst source. – John Lyon May 13 '12 at 23:20
  • Chocolates are made of spider blood - aren't they? – user unknown May 14 '12 at 04:59
  • Why does this factoid only ever say **spiders**? Why not also flies, gnats, fleas, mosquitoes and all other manner of insects? That alone is enough for me to dismiss this as myth. –  Jul 23 '18 at 18:02
  • @MichaelK Maybe because Mites (Alcari) are in fact spiders. Mites (Alcari) belong to spiders. Pneumonyssus simicola is one of many species which also live in funny places like lungs of Apes. Dermatophagoides (house dust mites) are nearly everywhere. You will breathe in parts and leftovers and shit of them every night. The smalles known fly is 4 times the size then the smallest known adult mite... and as said before mites are virtually everywhere. Fleas are rather large compared to them. Gnats giants. So what du you think you will breathe in more often? A spider with 100 μm or a 1500 μm gnat? – Offler Jan 07 '19 at 11:25

4 Answers4

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This is an utter fabrication.

It is thought to have started with an article in PC Professional Magazine regarding ridiculous facts circulating via e-mail.

In a 1993 PC Professional article, columnist Lisa Holst wrote about the ubiquitous lists of "facts" that were circulating via e-mail and how readily they were accepted as truthful by gullible recipients. To demonstrate her point, Holst offered her own made-up list of equally ridiculous "facts," among which was the statistic cited above about the average person's swallowing eight spiders per year, which she took from a collection of common misbeliefs printed in a 1954 book on insect folklore. In a delicious irony, Holst's propagation of this false "fact" has spurred it into becoming one of the most widely-circulated bits of misinformation to be found on the Internet.

From Snopes.com

However, the Snopes article itself has been called into doubt, with claims that Snopes made up the reference.

Oddthinking
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ElendilTheTall
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    interestingly, citing Lisa Holst and her PC Professional article as the source of the myth has become a bit of a myth itself: http://www.eightspiders.com/2008/08/why-eight-spiders.html – Oliver_C Apr 08 '11 at 15:39
  • Hmmm...so one person couldn't find a an article written 15 years ago (before everything went online). And Lisa Holst must be a fairly common name. – ElendilTheTall Apr 08 '11 at 16:05
  • well, apparently even the Library of Congress doesn't know about a "PC Professional Magazine" (the book from 1954 however does exist). Is there any other website that mentions Lisa Holst's article without copying/referencing Snopes? Is this article mentioned anywhere else, maybe in another context (after all it wasn't just about spiders)? – Oliver_C Apr 08 '11 at 18:07
  • I assume the Library of Congress only records American publications: nothing to say PC Professional was an American magazine. A quick search does indeed reveal plenty of references to the story without referencing Snopes. – ElendilTheTall Apr 08 '11 at 18:59
  • The LoC does have foreign publications (see the mentioned "Professional Computing" published in the 1980s in Peru). Could you please point me to one website that references the Lisa Holst article with a source other than Snopes? – Oliver_C Apr 08 '11 at 20:29
  • Or any other reference to PC Proffessional in general would be nice, because I'm not finding anything, not in other languages or in newspapers. The name Lisa Holst could be German or Swedish, which would make the search a little harder, but I'm not quite sure how this article can be so damned influential yet no one can find the text. – Scott Hamilton Apr 12 '11 at 20:10
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    There is now [a question](http://skeptics.stackexchange.com/questions/2094/is-a-writer-named-lisa-holtz-responsible-for-the-belief-that-everyone-eats-eight) regarding the Lisa Holtz source. – Jason Plank Apr 13 '11 at 23:45
  • @Elendil you should update this answer to clarify that this is likely to be a fabrication, but the underlying source that Snopes cites cannot be verified. – John Lyon Aug 23 '11 at 06:57
  • I've downvoted this answer as the magazine *PC Professional*, as far as anyone can tell, never existed. Many people (myself included) have written to Snopes about this and not had a response. I would suggest that we put Snopes in the "Wikipedia" bucket for not being a good primary source. – John Lyon May 02 '12 at 23:37
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    Seriously, I can confirm that there was (maybe still is) a PC magazine called "PC Professionell" ending in the german (latin?) suffix ~ell, not ~al. Here is an [ebay auction with a 1991 magazin](http://www.ebay.com/itm/VINTAGE-APRIL-1991-PC-PROFESSIONELL-MAGAZINE-GERMANY-OLD-ADS-/261013343664?pt=LH_DefaultDomain_0&hash=item3cc59b8db0) [Here is a press artigcle from 2001](http://www.heise.de/newsticker/meldung/Corel-Gratisversion-nur-halbe-Sache-37352.html). – user unknown May 14 '12 at 05:19
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    That's likely a fake snopes article – Sklivvz Oct 06 '16 at 17:10
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From Rod Crawford (Curator of Arachnids, Burke Museum)

For a sleeping person to swallow even one live spider would involve so many highly unlikely circumstances that for practical purposes we can rule out the possibility. No such case is on formal record anywhere in scientific or medical literature.

[...] I remain unconvinced that a spider would visit a huge breathing monster and enter its mouth.

Unless a spider is so small that it wouldn't realize that the "hole" is the mouth of a large predator, it's probably unlikely that a spider would crawl into it.

Oliver_C
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  • I invoke "The theory of large numbers", given enough opportunity even very unlikely events occur in significant numbers. However, as it is probable that someone has in their lifetime swallowed a spider in their sleep, it is still unlikely that on average a human will swallow > 1 spider. – Richard Stelling Apr 08 '11 at 14:11
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    Spiders (and various other invertebrates) can detect high concentrations of carbon dioxide and avoid it, presumably to avoid mouths (and even the skin of large creatures that may crush them accidentally). So spiders, no matter how small, do realize that mouths, no matter how big, are to be avoided. (Incidentally, mosquitos use these CO2 sensors in reverse--instead of running away, they run towards....) – Rex Kerr Apr 08 '11 at 23:35
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    *"(Incidentally, mosquitos use these CO2 sensors in reverse--instead of running away, they run towards....)"* So how many mosquitoes does the average person swallow a year? – tcrosley May 15 '15 at 09:12
  • @tcrosley: Motorcyclist, or non-motorcyclist? – DevSolar Oct 07 '16 at 08:41
  • Mites (Alcari) belong to spiders. You sometimes talks about mites the size of 100 to 400 µm. Pneumonyssus simicola is one of them which lives in the lungs of .. apes. So they are activly searching for this "huge breathing monsters" – Offler Jan 07 '19 at 11:16
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The Straight Dope claims that one person may accidentally swallow a large number of spiders after an egg sac bursts:

Put it all together, and it would be a miracle for a spider to end up in anyone's mouth while they're sleeping, except for one rare circumstance--when a spider egg sac hatches indoors. At that point, you can have hundreds of microscopic spiders, a millimeter long or less, leaping into the air in a short time span (under an hour total) and trying to ride the air currents to freedom.

However, these events should be rare and the author argues that average number of spiders swallowed being so high seems doubtful:

After all, most people breathe while they sleep (at least I do) and spiders, like virtually all arthropods, flee from breath. After all, there are lots of vertebrates that EAT arthropods, and if you're an arthropod and something is breathing on you, it's not a good idea to stick around. Simple enough.

So, it seems unlikely, but the arguments given in this particular article aren't conclusive.

Casebash
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    Just thinking about sack of spiders bursting in my mouth and then being swallowed makes me .... https://www.youtube.com/watch?v=payt4sD5nro – Matas Vaitkevicius Jan 27 '16 at 14:45
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The 1992 book Basic Statistics for the Behavioral Sciences Student Workbook and Study Guide says:

b.This is a very low p, indicating that, over the long run, we can expect to swallow spiders only 5 out of every 10,000 times we sleep.
c. Since p is not zero, we do expect to swallow spiders sometimes, and we don't know when it will happen.

This appears to be just a hypothetical statistics problem, but it could have been easily misunderstood as actually indicating that people swallow a certain number of spiders.

DavePhD
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