The surprisingly deep history of trouser technology.

Whence came pants? I'm wearing pants right now. There's a better than 50 percent chance that you, too, are wearing pants. And neither of us have probably asked ourselves a simple question: Why?

It turns out the answer is inexplicably bound up with the Roman Empire, the unification of China, gender studies, and the rather uncomfortable positioning of man atop horse, at least according to University of Connecticut evolutionary biologist Peter Turchin.

"Historically there is a very strong correlation between horse-riding and pants," Turchin wrote in a blog post this week. "In Japan, for example, the traditional dress is kimono, but the warrior class (samurai) wore baggy pants (sometimes characterized as a divided skirt), hakama. Before the introduction of horses by Europeans (actually, re-introduction - horses were native to North America, but were hunted to extinction when humans first arrived there), civilized Amerindians wore kilts."

The reasons why pants are advantageous when mounted atop a horse should be obvious, nonetheless, many cultures struggled to adapt, even when their very existences were threatened by superior, trouser-clad horseback riders.