Well, you should know what a beard is, but if you are interested in reading more about beards, biological, historical etc, I urge you to read the wikipedia page “Beard”. It contains lots of information, history and pictures, and explanation of beards.
A beard is the collection of hair that grows on the chin, upper lip, cheeks and neck of human beings and some non-human animals.
In humans, usually only pubescent or adult males are able to grow beards. However, women with hirsutism, a hormonal condition of excessive hairiness, may develop a beard. When differentiating between upper and lower facial hair, a beard specifically excludes the moustache.
Throughout the course of history, societal attitudes towards male beards have varied wildly depending on factors such as prevailing cultural-religious traditions and the current era’s fashion trends. Some religions (such as Islam and Sikhism) have always considered a full beard to be absolutely essential for all males able to grow one, and mandate it as part of their official dogma. Other cultures (while not officially mandating it), view a beard as central to a man’s virility, exemplifying such virtues as wisdom, strength, sexual prowess and high social status. However, in cultures where facial hair is uncommon (or currently out of fashion), beards may be associated by some with poor hygiene or a “savage”, uncivilized, or even dangerous demeanor.