A new study conducted at the University of Sheffield in Britain suggests that the reason humans are covered in small, nearly invisible body hair is so that we can detect bugs crawling on our skin.
During the study, researchers shaved the arms of some participants and left the hair on others. Then they placed bed bugs on each subject’s arm and waited to see how long it took for each subject to notice the movement of the bugs. Those with arm hair noticed the movement much sooner than those without leading the researchers to conclude that the hair allows us to detect the movements of things crawling on our skin. One thing to note was that men seem to detect movement quicker presumably because men are more hairy than women.