You're looking at it the wrong way. Not why do we have beards, but why did we lose all our other hair?
Cats don't have beards, because cats have fur.
On the premise that beard is testosterone triggered hair we would think that it was different from the neck hair of cats as both genders have that, though I can't say if males have more hair there in many mammal species, aside from those which have so much we call it a mane.
You're looking at it the wrong way. Not why do we have beards, but why did we lose all our other hair?
Cats don't have beards, because cats have fur.
Because it's harder to shed heat when you're covered in fur.
Saw the docu Becoming Human today and that was the main theory they purported. Didn't catch why we managed to keep things like pubic hair (which always confused me), head hair made sense in colder climes, and thick hair growth on the body is connected to testosterone in humans (unrelated to the docu).
Pubic hair is springy and acts as a damper during a certain motion. Many people that shave it off have irritation there, and not from the hair growing back or being scratched by stubble.
You're looking at it the wrong way. Not why do we have beards, but why did we lose all our other hair?
Cats don't have beards, because cats have fur.
Because it's harder to shed heat when you're covered in fur.
Saw the docu Becoming Human today and that was the main theory they purported. Didn't catch why we managed to keep things like pubic hair (which always confused me), head hair made sense in colder climes, and thick hair growth on the body is connected to testosterone in humans (unrelated to the docu).
From my understanding its body temperature regulation and before human lost the ability to do phomena some of that to.
I'm not an expert on this by any means, but here's a side-note:
Humans have been incredibly good hunters because they hunted through endurance hunting. They simply could chase animals for so long that the animal would become exhausted while the human could keep going. We managed that through temperature regulation--we sweated and we had very little body hair. Without that fur, we would not overheat and dehydrate and all that bad stuff.
As far as pubic hair goes, I have no idea for females, but I speculate (only speculate) that pubic hair might have stayed on men, potentially and partially, to help keep the epididymis warm so that sperm didn't die. I learned in high school health classes that sperm needs a remarkably regulated temperature to stay alive and so I'm guessing some sort of link from that to pubic hair.
I'd say that is probably not the reason. If you want them warm you can just have them closer to or even up in the body. They are outside of it in the first place for the lower temperature.
Ooh! Then an adventurer could quest around the world, earning the trust and learning the techniques of the legendary senseis as he went! (And yes, I know the plural of sensei is sensei; I changed it for clarity.)
Could have just thrown the word "many" in front of legendary.
The pubic hair adds surface. Pheromones etc. which are secreted on the crotch-region and under the arms are the cause for having hair there. Thats because said pheromones are secreted by sweat which can evaporate better on a bigger surface.
Thus being shaved in this regions brings problems. Because the sweat cant evaporate that good - on the compareable small surface of the pure skin - you create a biome for bacteria. This bacteria, if the growth is uncontrolled, lead to skin irritation. Mild to heavy infections can be be obtained if said bacteria get into wounds from the shaving process. So if you are shaved in your never-regions you should use anti-transpirants etc. to control the growth of bacteria. Also many bacteria can create a "stench" if theyr numbers are big enough.