Do You Really Swallow Eight Spiders a Year in Your Sleep? The Anatomy of a Myth
It is the perfect bedtime story to ruin bedtime. Somewhere along the way — at a sleepover, on a trivia card, in the comments under a science video — you almost certainly heard it: the average person swallows eight spiders a year in their sleep. Eight. While dreaming. While the legs tap-dance past your teeth.
The image is so vivid it practically crawls. And that vividness is exactly why you should be suspicious. ProofNews put the claim where all viral claims belong: under the lamp of the evidence. We traced where the number came from, read what arachnologists and sleep biology actually say about it, and checked whether any scientist has ever documented a single case. The result is one of the strangest debunking stories we have ever published — because the origin story of this myth, as we will see, may itself be a myth.
The Claim, As It Circulates
The claim exists in several flavors, all equally specific and equally unsourced. The classic version: the average person swallows eight spiders per year while asleep. Variants say ten spiders, or that you swallow “several” spiders per night, or that you will swallow about 80 spiders in your lifetime. The details shift with each retelling; the core horror stays fixed. It appears in trivia books, on shock-fact social media pages, in classroom banter, and in forwarded emails that have been circling since the dial-up era. It is presented as settled science, a fun fact with the authority of a statistic.
But here is the first thing a fact-checker notices: nobody ever cites a study. There is no named researcher, no journal, no dataset, no year of publication. The number eight arrives naked, without any of the apparatus real statistics travel with — no margin of error, no population, no methodology. A real finding that humans swallowed spiders at a measurable rate would be astonishing. It would show up in sleep laboratories, in medical literature, in autopsy-adjacent research, in entomology journals. It shows up nowhere.
Britannica, in its coverage of the claim, has been plain about this: no scientific study has ever documented people swallowing spiders during sleep. Smithsonian Magazine’s reporting likewise found no record of the claim in any original study or observational report. When science outlets go looking for the paperwork, the file is empty. Every “statistic” has to come from somewhere, and this one’s birth certificate has never been found in any laboratory.
So where did the number come from? That question leads to one of the most delicious ironies in the history of internet misinformation.
The Origin Story: A Myth About the Myth
The most widely repeated origin story goes like this. In 1993, a columnist named Lisa Holst wrote an article in a magazine called PC Professional about the ubiquitous lists of “facts” circulating via email — the early internet’s version of viral content. She was making a point about gullibility: people would believe anything that arrived formatted like a fact. To demonstrate, she invented her own list of ridiculous “facts,” and among them was the statistic that the average person swallows eight spiders per year. The fake example escaped its cage and became one of the most widely circulated bits of misinformation on the internet. The fact-check site Snopes published this account on its page about the claim, and for years it was treated as the authoritative explanation: the myth was born as a deliberate demonstration of how easily myths are born.
There is just one problem. The origin story itself does not hold up to inspection.
Researchers and curious readers who tried to verify the 1993 article found almost nothing. The columnist, the column, and the magazine leave barely a trace in the historical record outside of the spider story itself. When a blogger who ran a site about the myth called the Library of Congress to ask about PC Professional, he was told they had no record of the magazine. The whole thing began to smell — and then Snopes posted a follow-up that turned the story upside down: the “Lisa Holst” account was itself a piece of misinformation. The full name given in the original Snopes telling, “Lisa Birgit Holst,” is an anagram of “this is a big troll.” Snopes had published the origin story as a joke, an April-style prank aimed at showing how easily readers swallow fabricated “facts” — and in the process, its fabricated explanation became the accepted history of the myth, repeated by science writers and fact-checkers for years.
Read that twice, because it is the whole story in miniature. A made-up explanation for how misinformation spreads became one of the most widely circulated pieces of misinformation. Snopes, a fact-checking institution, manufactured a fake history of a fake statistic to demonstrate how fake histories spread, and the demonstration worked so well that it colonized every debunking of the claim that followed. Even the debunkers got debunked.
Mental Floss, digging into this tangle, added that Snopes’s version said Holst had taken the spider figure from a collection of common misbeliefs printed in a 1954 book on insect folklore — another layer of “source” that leads nowhere checkable. The honest position, as of April 2026, is that the precise origin of the eight-spiders figure is inconclusive. What is certain is that it never came from a study, an experiment, or any kind of observation. It came from somewhere in the folklore-to-internet pipeline — possibly a made-up example, possibly an email-forward invention, possibly a joke — and it survived because it was too good not to share.
What Spiders Actually Do
Now set the folklore aside and look at the animals. Arachnologists — the scientists who actually study spiders — treat this claim the way physicists treat perpetual-motion machines: with weary patience. Their objections are not nitpicks; they are about the fundamentals of both spider biology and human biology.
Rod Crawford, the curator of arachnids at the Burke Museum in Seattle, has addressed the claim in interviews with Scientific American, and his verdict is the one every arachnologist echoes: “This notion flies in the face of both spider and human biology.” That is eight words that settle the matter from the people who know spiders best. Bill Shear, a biologist at Hampden–Sydney College and a former president of the American Arachnological Society, has explained the same conclusion from the spider side in Scientific American’s coverage: everything about how spiders sense the world and where they choose to go argues against this scenario.
Consider what a sleeping human is to a spider. Spiders are exquisitely sensitive to vibration — their legs are studded with sensory structures that read the world as tremors. A sleeping person is a seismic event: breathing, heartbeat, snoring, tossing, the thump of a pulse transmitted through a mattress. To a small animal that hunts by stillness and startles at footfalls, a human bed is not a quiet meadow; it is a construction site. Spiders avoid large, warm, moving animals as a matter of survival instinct, and humans are the largest moving animals in most houses.
Spiders also read chemistry. They are sensitive to carbon dioxide and to heat — both of which a sleeping human emits in generous quantities. A face exhaling warm, CO2-rich air is not an inviting cave to a spider; it is a warning beacon. And the supposed destination is even less appealing. A human mouth is warm, wet, muscular, full of teeth, and attached to a creature that twitches, swallows, coughs, and wakes. Spiders seek quiet, dry crevices and corners where they can wait for prey in stillness. Nothing about an open mouth — a moving, breathing, snoring trap that periodically fires a tongue across it — matches what any spider wants from real estate.
Arachnologist Catherine Scott has put the point even more bluntly for a general audience: “This myth has no basis in fact. It’s just not something spiders do.” That is worth sitting with. Not “it’s rare.” Not “it hasn’t been measured.” It is not something spiders do. The animals whose behavior the claim depends on are, by every account of the people who study them, simply not in the business of marching into sleeping mouths.
Could it ever happen? Science is cautious about the word “never,” and arachnologists generally concede the theoretical possibility of a freak accident — a spider blundering onto a face, a sleeper inhaling at exactly the wrong moment. But that is not the claim. The claim is a regular, measurable, eight-per-year event happening to the average person. There is no documented case of it happening even once in the ordinary sense the myth requires, let alone at a rate of eight per year. An event so rare it has never been recorded cannot be an annual routine.
What Sleeping Humans Actually Do
The spider side is only half the problem. The human side of the claim quietly assumes that a sleeping person is a passive tube — a mouth left open like a garage door while spiders file in. Real sleep is nothing like that.
Most people do not sleep with their mouths hanging open all night. Many sleep with mouths closed or semi-closed, breathing through the nose. Even habitual mouth-breathers are not motionless: sleep involves constant micro-movement, position shifts, twitches, and swallowing. The gag and cough reflexes remain on duty. A spider crossing a lip or touching a tongue would be, from the nervous system’s perspective, an emergency, not a snack. The likely outcome of a spider touching a sleeping face is that the sleeper flinches, brushes, snorts, or wakes — the body has layers of defense against foreign objects near the airway, because choking on foreign objects is a real danger that evolution has spent millions of years guarding against. These reflexes do not switch off at bedtime; they are the reason we do not routinely choke on our own saliva, let alone on wandering arthropods.
Snoring, which the myth’s imagery seems to require, actually makes the scenario harder, not easier. A snoring sleeper is producing noise and vibration at close range — the exact signals spiders avoid — and generating irregular blasts of air through the very passage the spider would have to enter. The picture of spiders queuing politely to enter a snoring mouth reverses the biology: the snoring mouth is the least spider-friendly structure in the bedroom.
Then there is the arithmetic the myth never does. Eight spiders per year is roughly one spider every six weeks, for every person, year after year. Think about what that would mean in observable reality. Sleep laboratories monitor thousands of sleepers with cameras and sensors; dental and airway specialists examine mouths daily; entomologists study household spider populations in detail. An event happening billions of times a year worldwide — eight times 8 billion is 64 billion spider-swallowing incidents annually — would be one of the most common human-wildlife interactions on Earth. It would be in textbooks. It would be a known factor in sleep medicine, a variable in entomology, a line in public health statistics. Instead there is silence: no case series, no sleep-lab footage, no entomological survey, no medical report. A phenomenon of that scale cannot hide from every instrument pointed at it for decades.
Why the Number Sounds So Believable
If the claim is biologically absurd and evidentially empty, why has it survived for thirty years? Because it is engineered — by accident or design — to bypass our skepticism and lodge in memory.
First, it has a number. “Eight spiders a year” sounds like a measurement. Numbers confer an unearned authority; they suggest someone counted. The specificity of “eight” is doing enormous rhetorical work. Had the myth said “some spiders,” it would feel vague and dismissible. “Eight” feels like data, even though no data exists behind it. This is one of the oldest tricks in the misinformation playbook: precision as a substitute for evidence.
Second, it weaponizes disgust. Humans have a powerful, ancient disgust response, and the image of spiders in the mouth hits it dead center. Disgusting claims are memorable claims — psychologists have shown repeatedly that emotionally arousing content, especially disgust, is shared more and remembered longer than neutral information. The myth does not survive because it is plausible; it survives because it is unforgettable. Every retelling is a small dose of horror delivered as a “fun fact,” and horror is the best marketing.
Third, it is almost impossible to disprove from personal experience, which gives it a strange immunity. You cannot observe yourself sleeping. The claim occupies the one part of your day you can never witness, so your own lack of spider-in-mouth memories proves nothing either way. Myths that live in unobservable territory — dreams, the deep ocean, the far side of the moon — are hard to kill because nobody can produce the definitive personal counterexample. The only counters are the ones this article has used: biology, probability, and the absence of evidence where evidence should be abundant.
Fourth, it flatters the teller. Sharing a gross “fact” is a social performance: the teller gets to play the insider with secret knowledge, and the audience’s squirm is the reward. The myth spreads at sleepovers, in classrooms, and in comment sections precisely because the reaction it produces is the point. It is not really a claim about spiders; it is a claim about the kind of person who knows shocking things.
And fifth — the deepest irony — the myth has repeatedly been “debunked” in ways that spread it further. Every article explaining that you do not swallow spiders repeats the number eight, the image, the scenario. Psychologists call this the illusory truth effect’s ugly cousin: repetition increases familiarity, and familiarity feels like truth, even when the repetition comes with a “false” label. The Lisa Holst episode is the extreme version of the same dynamic: an explanation of the myth became part of the myth. Debunking this claim will always be a little like fighting a fire with a flamethrower — which is why the verdict has to be stated as plainly as possible.
How to Think About “No Evidence”
A careful reader might object: absence of evidence is not evidence of absence. Fair — in the abstract. But there is absence of evidence, and then there is the absence of evidence where evidence would be unavoidable.
If the average person swallowed eight spiders a year, spiders would be turning up in sleep studies, in dental records, in emergency-room anecdotes from credible clinicians, in entomological surveys of bedroom fauna, in the published observations of the thousands of arachnologists who have spent careers watching what spiders actually do around humans. Pest-management professionals — people who spend their working lives inside other people’s houses, observing spider behavior at close range — report that the spiders living in homes are solitary, shy, and far more frightened of us than we are of them, and they stay away from beds and bodies. The claim does not merely lack a supporting study; it lacks the entire ecosystem of traces that a real, common phenomenon would leave behind. That is not a gap in the research. That is the research’s answer.
It is also worth noting what the myth quietly gets wrong about spiders as housemates. The spiders in your home are mostly hunting in stillness: in corners, behind furniture, along baseboards, in the quiet zones where small insects travel. Your bed is the loudest, warmest, most vibration-soaked piece of furniture you own. A spider has no prey to catch on your face and no shelter to find in your mouth. There is no motive in the story at all — which is why the myth never explains why the spiders are doing this. They are not. That is the whole explanation.
The Verdict
False. The claim that the average person swallows eight spiders a year in their sleep has no basis in fact.
No scientific study has ever documented people swallowing spiders during sleep — not one case in the ordinary sense the myth requires, let alone eight per year. The number eight has no source in any research, experiment, or observation; the most widely repeated origin story (a fabricated 1993 magazine example by a columnist demonstrating how misinformation spreads) is itself unverifiable and was later revealed to be a joke — “Lisa Birgit Holst” being an anagram of “this is a big troll.” Arachnologists are unanimous and blunt: Rod Crawford of the Burke Museum says the notion “flies in the face of both spider and human biology,” former American Arachnological Society president Bill Shear’s assessment points the same way, and arachnologist Catherine Scott states flatly that “this myth has no basis in fact” and “it’s just not something spiders do.” Spider biology argues against it — spiders detect vibration, heat, and carbon dioxide and actively avoid large, noisy, moving animals. Human sleep biology argues against it — mouths are mostly closed, reflexes stay on duty, and sleepers flinch, cough, and swat at intrusions. And the arithmetic argues against it: eight spiders per person per year would mean tens of billions of incidents annually, a phenomenon that could not possibly escape every sleep lab, clinic, and entomologist on Earth.
The myth survives because it is disgusting, specific, unobservable, and fun to share — not because it is true. It is a myth about gullibility that proved its own point so thoroughly that even the story of its origin turned out to be made up. If there is a moral, it is the one the original fabricators — whoever they were — intended all along: a number is not evidence, a vivid image is not a study, and “everyone knows” is the weakest citation in the world.
Sleep easy. The spiders are in the corners, doing spider things, and they want nothing to do with your mouth.
Sources consulted for this fact-check include Scientific American’s reporting quoting Burke Museum arachnology curator Rod Crawford and biologist Bill Shear (former president of the American Arachnological Society); Britannica’s coverage noting no scientific study has documented spider-swallowing during sleep; Smithsonian Magazine’s reporting finding no record of the claim in any original study; Snopes’s fact-check page and its follow-up on the “Lisa Birgit Holst” anagram; Mental Floss’s investigation of the unverifiable 1993 PC Professional origin story and the Library of Congress’s lack of records; and arachnologist Catherine Scott’s public debunking of the myth.
