One of the most widespread and unsettling sleep-related myths is that people swallow several spiders a year while sleeping. This idea has circulated for decades, often repeated as fact, but when examined closely, it does not hold up scientifically. The claim that spiders crawl into our mouths at night is more folklore than reality, and understanding why the myth persists requires a closer look at both human sleep behaviors and spider biology.
The origins of the myth are not based in scientific research but rather in misinformation. In the 1990s, a columnist writing about how easily false facts spread included the “eight spiders a year” claim as an example of how myths can travel quickly when repeated without evidence. Despite this, the idea stuck in popular culture and has been widely shared ever since.
From a biological perspective, spiders are not drawn to humans while they sleep. In fact, they tend to avoid us. According to arachnologists cited by the American Arachnological Society, spiders are sensitive to vibrations, and the sounds and movements humans make while breathing or shifting in bed would deter them from approaching. Sleeping with an open mouth may feel like an invitation to creepy crawlies, but in reality, spiders are far more interested in catching insects in corners of rooms than crawling into humans’ mouths.
Sleep science also helps debunk the myth. During sleep, especially in deeper stages such as slow-wave sleep, people’s bodies remain relatively still, but breathing patterns, snoring, and micro-movements all create disturbances that spiders are unlikely to overlook. Research from the Journal of the American Board of Family Medicine emphasizes that while many parasomnias such as sleepwalking and talking do happen, involuntary swallowing of spiders is not among them.
There is also no credible scientific evidence documenting cases of people eating spiders in their sleep. If it were a common occurrence, it would have been observed in sleep laboratories, where thousands of subjects have been monitored overnight for sleep studies. Yet not a single report has ever confirmed this phenomenon.
So why does this myth continue to persist? Part of it may be tied to humans’ natural aversion to spiders. Psychologists suggest that fear of spiders is deeply ingrained as a survival mechanism, making stories about them more memorable and easier to believe. In addition, myths like this play into our fascination with the strange and unsettling aspects of sleep, making them more likely to spread.
The conclusion is clear: you are not eating spiders in your sleep. While the thought may be unsettling, spiders have no interest in climbing into our mouths, and science offers no evidence that this myth is true. What the myth does highlight, however, is the importance of questioning commonly repeated claims about sleep and health, especially when they sound shocking.
Disclaimer: This article is for informational purposes only and is not intended as medical or scientific advice. For concerns about sleep health or parasomnias, consult with a healthcare professional.
References:
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American Arachnological Society. (2020). Common myths about spiders. Retrieved from https://www.americanarachnology.org
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Wertheim, M. (1993). The eight spiders a year myth. PC Professional.
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Mahowald, M. W., & Schenck, C. H. (2005). Insights from studying human sleep disorders. Nature, 437(7063), 1279–1285.
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Owens, J. A. (2008). Sleep myths and truths: Implications for health and safety. Journal of the American Board of Family Medicine, 21(2), 141–145.