Do We Eat Spiders in Our Sleep?

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You may have heard from a friend or colleague that we eat spiders in our sleep. I’ve even heard it said that you can eat up to 8 a night (but generally its 8 a year). It is a common urban legend, so here, I’ll investigate the possibility of eating spiders, and see if there is any truth behind it.


Spider Science

Spiders are extremely well adapted to survival, and it is no wonder that they have thrived in almost every corner of the world. Along the legs of spiders are chemoreceptors1 , which to you and me, is something similar to a nose. These chemoreceptors on the legs of spiders can sense a number of chemicals, and are there to avoid predators, and to seek out prey.

If a spider was to come close to a human mouth it would sense the many 1000’s of different chemicals in their breath. From the toothpaste, to the evening meal and even the carbon dioxide we breath out. A spider would be able to tell that a massive and dangerous mouth is nearby, and it would move in the opposite direction.


Unlikely odds

When people hear that they eat spiders in their sleep, they often imagine a tiny spider dangling on a web down into your gaping mouth by accident. However, this isn’t likely to be the case. Most people will instinctively sleep on their side or their front, not their back, which means that a spider must actively crawl into your mouth. based on their highly sensitive chemoreceptors (and not to mention their eyesight) its very unlikely that they will ever crawl into a mouth.

Furthermore, when you are asleep, your mouth is far from being gaping. In fact, your mouth rarely opens more than 25% of its full open position, which means the gap for a spider to ‘accidentally’ fall into, or even crawl into, is quite small. This makes it very unlikely that a spider would end up in your mouth.


Near impossible to measure

Aside from the above 2 points, which make the chances of a spider going into your mouth extremely small, how would we ever measure this? Think about it – how (and why) would researchers go about counting how many spiders people eat in their sleep in a year. They would have to carefully watch or film someone sleeping for a year, and count how many spiders go in their mouth. Ideally, this would have to be done for a large population size to minimise the risk of chance, and different sleeping locations (e.g in the country and in the city).

This would take a massive amount of time and money, and frankly, no one in their right mind would do it.



The chances of eating spiders in our sleep is extremely slim due to the spiders ability to detect/ avoid us, and the difficulty in getting into our mouths in the first place. The myth that we eat 8 spiders a year is nothing more than a myth, simply because testing for it is too difficult, and pointless.

So, you can sleep safe in the knowledge that you won’t be eating any spiders tonight (or rather, the changes of eating spiders is very very low).



1. Encyclopedia of Entomology, Volume 4, By John L. Capiner

Image courtesy of  Martin Cooper


This Youtube video will give an overview of the information found on the article tab. If you want to know more about the topic, or want to see where the information came from, have a read of the article after you watch the video.

No one knows for sure, but the chances of you eating any spiders in your sleep are extremely low.