Why do men have short hair and women long?

It always amazes me to look at a group photo from late 1960s, the 1970s and early 1980s Ireland, nearly without exception every man has long hair, even elderly men. I’m sure this was the case elsewhere.

I remember when LBJ left office, he grew his hair pretty long, by presidential standards. Arch conservative Barry Goldwater was asked what he thought of LBJ’s unshorn locks, and he replied something to the effect of, “I think it is great; when I retire, I’m going to grow my hair down to my ass.”

[QUOTE=brazil84]
I would have thought that height, muscles, and jaws serve practical purposes too. As opposed to large breasts.
[/QUOTE]
Large breasts have practical purposes. They’re really good for keeping crumbs from falling in your lap.

And if you have them properly cantilevered, you can rest your drink on them. Not to mention the ability to store considerable amounts of paper money between them, given the proper undergarments.

[QUOTE=brazil84]
I would have thought that height, muscles, and jaws serve practical purposes too. As opposed to large breasts.
[/QUOTE]
Large breasts serve as a display to males that a woman has enough body fat to be fertile; concentrating it in one area makes it more visible; the fat itself is useful as well. That’s one theory at least.

And attracting males IS a practical purpose, from a biological perspective.

[QUOTE=brazil84]
But anyway, putting aside aspects of the human body that are genetically determined and looking at peoples’ day to day behavior, it definitely seems like women are the “flashy” sex.
[/quote]
I’d call men and women flashy in different ways. Women, on average, tend to go to more trouble for flashiness in terms of pure looks. Men tend to show off in other ways, like bragging, feats of strength, taking risks, etc. Showing off your “manliness” by daredevil behavior is just as flashy as wearing a tight dress ( and rather more likely to get you splattered ).

[QUOTE=brazil84]
I wonder if this has been scientifically studied or not. Certainly there is genetic variation in peoples’ ability to grow long hair. Does this variation correlate with sex at all? I wouldn’t dismiss the possibility.
[/QUOTE]
I seem to recall reading somewhere that women’s hair will on average grow longer than men’s if left uncut, but I haven’t been able to find a cite.

[QUOTE=Der Trihs]
Large breasts serve as a display to males that a woman has enough body fat to be fertile; concentrating it in one area makes it more visible; the fat itself is useful as well. That’s one theory at least.

And attracting males IS a practical purpose, from a biological perspective.
[/quote]

That’s obviously true, but it’s not quite what I had in mind when I defined “flashy” as “something that is relatively less practical but is perceived to enhance one’s appearance.”

But is it more likely to get you laid? I’m not sure. Certainly that argument could be made about a display of wealth, such as a fancy car.

I recall reading that too.

[QUOTE=danceswithcats]
And then He, summoning His disciples, did travel unto the city of Capernaum, and therein did find a tonsorial salon. Entering, He spake unto the keeper, saying, “Render unto us all a High and Tight.”
[/QUOTE]

…and verily did the tonsorial salon keeper spake unto Him saying “Do you have an appointment?”

And He was mightily vexed and smote the salon keeper and spake thus " Do you knowest who I am?"

And the salon keeper said unto Him “I don’t give a shiteth pal, no appointment no tonsorial trimmings”

And it came to pass that He and His disciples were rendered speechless and returneth to the inn and got mightily smashed

[QUOTE=KidCharlemagne]
Roman men cut their hair so that it couldn’t be grabbed during battle. It stands to reason that short hair became associated with warriorhood and masculinity.
[/QUOTE]
Actually, that’s from a few hundred years earlier. Alexander the Great insisted on his soldiers being clean-shaven or with very short beards, so their enemies couldn’t grab them by the beard during battles. And short hair (for that time), too – short enough that it didn’t hang outside of their helmets.

He got a lot of complaints about this. They complained that no beard and short hair was ‘un-manly’ and made them look like boys, not men. But he was the boss. (And, really, when he’s barely out of his teens, and has already conquered most of the known world – well, it’s hard to make that argument stick.)

But the Romans imitated this Greek trend (like a lot of things). During most of the Roman Republic, the Consuls and leading Senators, and the first dozen or so Roman Emperors were all clean-shaven.