A
beard is the collection of
hair that grows on the
chin,
upper lip,
cheeks or
neck of
humans and some non-human animals. In humans, usually only
pubescent or
adult males are able to grow beards. From an evolutionary viewpoint the beard is a part of the broader category of
androgenic hair. It is a
vestigial trait from a time when humans had hair on their face and entire body like the hair on
gorillas. Since hair bore parasitic bugs and ticks, as humans evolved they lost more hair, due to the advantage that a more
glabrous body prevented parasitic bugs. The evolutionary loss of hair is pronounced in some populations such as
indigenous Americans and some east Asian populations, who have less facial hair, whereas
Caucasians and the
Ainu have more facial hair. Women with
hirsutism, a hormonal condition of excessive hairiness, may develop a beard.
