“The average person swallows eight spiders a year in their sleep.”

The notion that an average person unknowingly swallows several spiders each year while sleeping is a pervasive urban legend with a rather ironic origin. While its precise beginnings are somewhat unclear, a popular theory traces this myth back to a 1993 magazine article. The "eight spiders a year" claim was reportedly fabricated as a joke to illustrate how readily misinformation could spread, particularly online. Ironically, this fictional fact then took on a life of its own, becoming one of the most persistent and widely believed false statements, proving the very point it sought to make.

Scientifically, there is no credible evidence to support this unsettling claim. Spiders are highly unlikely to venture into a sleeping human's mouth. These arachnids are sensitive to vibrations, and the regular sounds and movements of a sleeping person—such as breathing, heartbeats, and shifting—would deter them. Furthermore, spiders prefer quiet, undisturbed environments for building webs and finding prey, making a human mouth, which is often closed and emits warm, moist air, an extremely undesirable location. From a spider's perspective, a human is a large, potentially dangerous predator (Review) to be avoided.

The enduring belief in this myth can be attributed to several factors. Its shocking and memorable nature makes it a compelling story that people are inclined to share. Additionally, the widespread human fear of spiders, known as arachnophobia, plays a significant role, as people are often more receptive to information that confirms existing anxieties, even if it lacks a factual basis. The ease with which such a vivid and unsettling image can be processed and passed along contributes to its longevity as a common misconception.