Hairyness
I was thinking about leg & underarm hair yesterday (the bane of many women's lives). Yeah, we're constantly trying to get rid of all that hair, but aren't we lucky that we don't have to keep TRIMMING it? I mean, it's bad enough that we have to pluck it or wax it out or whatever, but at least if you don't you won't find your legs suddenly swamped by a forest of hair gone beserk.
And then I realised, hey, only hair on the top of the head keeps growing and growing. Hair on the rest of the body only grows to a certain length, then stops. Why is that??
Being a curious sort of person (with perhaps a little too much time on my hands... but not as much as these people), I decided to ask the Internet. In other words, I googled it lah.
Well, I discovered that the hair follicles on the rest of the body have been programmed to have a short "growth phase" whilst the hair follicles on the head have been programmed to have a much longer "growth phase". In fact, hair transplants don't work if you try moving hair from the head to another part of the body, or vice versa.
"When researchers transplanted hair from the head to the leg, it kept growing," Neufeld says. "It didn't grow as long as it would on the head, but the hair grew much longer than typical leg hair."
—ScienceDaily: Researchers Conclude Head Hair & Fur Are Not The Same
But why is hair on the head programmed for a longer period of growth than hair on the rest of the body?? This still didn't tell me why.
Apparently nobody really knows why. According to Wikipedia, "Anthropologists speculate that the functional significance of long head hair may be adornment, a byproduct of secondary natural selection."
It even goes on to say that long head hair could have something to do with selection of a mate: "...long lustrous hair is a visible marker for a healthy individual (with good nutrition, waist length hair預pproximately 1 meter or 39 inches long謡ould take around 80 months, or just under 7 years, to grow)." No wonder so many guys like girls to have long hair. And no wonder St Paul wrote that "if a woman has long hair, it is her glory"!
Wait a minute, I have short hair. No wonder I'm still single lah -- it's all my hair's fault!