So, why haven't bald men gone extinct?

Years ago, back in California, I asked a colleague--a biologist--why we don't have a greater variety of colors when it comes to hair on our bodies.  The thought was triggered by the daily sights of students, almost always women, with so many colors on their heads, thanks to the dyes humans have developed.

Her reply didn't satisfy my curiosity.  Or, perhaps, I was too stupid to understand her answer?

A few months after that thought, I was shocked at a more personal revelation--I was beginning to develop the typical male bald patches.

A course that I taught had students in the same classroom and students at another off-campus site. The class was held at a television studio-classroom, and images and sounds from the studio were sent in real time to the off campus, and the video and audio from there were beamed back as well.  The off-campus room had only one camera, while the classroom where I was had a camera turned towards the instructor (me) and another from behind me to capture the students.

There was a monitor in my view where I could see the images from the cameras.  And that is when I caught the image from the camera that was behind my back--it showed the back of my head with the (then) thinning hair where the scalp was beginning to shine through.

It was so much a shock that I remember commenting right there something along the lines of "wow, I am going bald!"

Since then, the hairline in front has receded a lot.  The back has become a lot smoother.  When raindrops fall, as they do for nine months of the year here in Oregon, there is very little hair on top to act as shock-absorbers, and I can feel every drop falling like a pebble.

Over the years, the question about hair, in terms of colors, has, therefore, and understandably so, morphed into why there is baldness at all.  Does it serve any evolutionary purpose?  If it does not, and if baldness is a disadvantage, then can we expect bald people to become extinct?

Robb Dunn comments on the question of "why haven't bald men gone extinct?" in the New Scientist.

The hair on our heads may protect us from the noonday sun, maintain body heat when it is cold, and even attract a mate. If so, men who lose their hair are at a disadvantage, and you would expect natural and sexual selection to have weeded them out. So why haven't bald men like me, or at least our versions of genes, gone extinct?

Turns out that it is a teaser essay, without any real explanations; the mystery continues :(

It seems like the rate at which I am balding is far from steady but increases every single day. 

A couple of weeks ago, I wondered how I might look like if (when?) I become fully bald.  So, in a typically scientific approach, I headed (pun intended!) to the barbershop, and came out looking like this:

A few more steps to satisfy my curiosity, and I became:

I don't know about all the bald people, but I am well on my way to extinction :)