Why do humans have pubic hair? And likewise, do animals?
What if anything is it good for?
- ask this because my grandson asked me. DUH. Was my answer.
Not all adult humans do; as for animals, I’m reasonably sure ducks don’t, some mammal species have thicker fur in the groin area, others don’t… but the immense majority of mammals have fur all over whereas most of us only qualify for fuzz.
For us hairless monkeys it appears to be one of those traits which has evolved based on whatever-was-considered-attractive by the local possible bedmates or on being linked genetically to another more-beneficial trait.
The naturalist Desmond Morris has many speculations on this and other obscure human traits. That name, Desmond Morris is the citation, and yes, his information, is very speculative, so you should take it all with the appropriate amount of salt …
He thinks pubic and armpit hair is there to concentrate our scent for air dispersal. His books have cute little diagrams of the the naked biped with wind blowing through the respective areas, sending the pheromone communication. Or some such foo.
You probably won’t find a better explanation, people tend to go straight to Desmond Morris on any such topic, because he’s so prolific. But my college professor on evolutionary bio said that he really generates lots of speculation from very little evidence.
Another theory for pubic and armpit hair is that helps to reduce chafing while moving. I’m not sure that one is any less speculative than the scent explanation. After all, kids would presumably have as much need for chafing protection as adults.
It may be as simple as advertising sexual maturity, though. It makes as much sense as breasts, chest hair and deep voices.
A more tongue-in-cheek explanation: the need to shave sped up the development of sharp stone tools. 
This topic came up before, and someone posited this. But the difference was to reduce chafing during sex. I guess that makes sense.
What do you mean by “why”? What makes you think there’s a reason for it?
Wouldn’t that hurt like hell? Scientifically speaking of course.
“Scientiifcally speaking”, I’m sure my Grandson will understand these answers even if I don’t.
Thank all of you for these very interesting answers. J.
Chafing is largely dependent on sweating, it seems. No sweat, no chafe, even with the exact same motion of similar duration between body parts. Children don’t sweat near as much as post-pubescent, hairy people. IIRC the U.S. Army has conducted tests that have shown that blisters are similarly dependent on moisture. Dry feet don’t blister, sweaty feet do.
Seems like if your armpits are getting chafed during sex, you’re doing it wrong (and will have little chance of passing on your genes)… 
I’ll vote for a combination of concentrating pheromones and catching and drying sweat. After all, eyebrows are most usefulfor preventing sweat from easily running into the eyes.Armpits are a good source of sweat, oddly enough (and some interesting glands for scents). Plus, the groin and armpits are areas (like the head) where body heat is easily lost if not insulated.
I suspect the hair in various places is not for one purpose so much as a congruence of multiple purposes, like most biological evolution.
There usually is some reason for biological traits. They might not have evolved because of direct selection, but because of linkage to some other trait; but the entire field of evolutionary biology is based on asking questions such as this.
The feature is particularly interesting since chimps and bonobos don’t seem to have armpit hair like humans do, which presumes it is a feature evolved in our lineage rather than a holdover from an ancestral condition. They apparently don’t have a pubic “bush” either.
Seriously? I was under the impression that the recent trend towards lack of pubic hair was artificial, not that I mind or anything.
I’m going for a sign of sexual maturity.
I thought Mr. Pubic Bush was there to protect the reproductive organs…
Aside from the fact that a patch of hair isn’t that great a line of defense, it mostly protects the pubic bone rather than the more sensitive bits of the anatomy.
I’m kind of surprised it took so long for someone to bring this up. If everyone is naked pubic hair is a great way to recognize from a distance whether a male or female is sexually mature. Facial hair is a great way to recognize someone as male from a great distance.