What is the evolutionary function of the male beard?

Question

Is there a reason as to why, for adult men, beards grow back every day, besides for obvious heat retention?

Answer 1

That is an interesting question.  Usually in the wild if a male or female have some kind of trait different from the other s*x it is for a purpose such as to be attractive.  Maybe in the early days hairy beards were attractive to women, and we just haven't stopped growing them.  

Answer 2

Its just a left over.

What is the value of the male nipple?

Answer 3

This is an interesting question.  

Attraction of the opposite s*x seems to be the most likely answer.

Human males retained beards because of sexual selection.

Just recently a study was conducted that found a relationship between attractiveness and facial stubble compared to no hair and a full beard.

So did facial hair coevolve with culture making shaving attractive today?  Who knows, but it is an interesting question.

As an aside, humans as a mammal are pretty much naked. So, another good question is why do humans not have as much hair as other mammals?  One possible answer is that it helped reduce the amount of parasites.  

Answer 4

There does not necessarily have to be a function in order for a trait to exist. As long as there is no distinct disadvantage to the beard's presence it may continue to exist as long as the species survives.

Answer 5

So how come a lot of East Asians and Native Americans don't grow facial hair at all? How about that?