Noun
the condition of being void of hair
the quality of not having hair
Source: WordNetHorses also sweat, and they are larger, hairier, and expend more energy running than human males, so there may not be any connection between the ability to sweat and the apparent hairlessness of humans. Source: Internet
Historically, some ideas have been advanced to explain the apparent hairlessness of humans, as compared to other species. Source: Internet