How warfare shaped human evolution

I am an insomniac so I'm still up at 4am Cambodian time. One last post and I'm off to bed, or I'll fall asleep in the shop tomorrow!

This one is from www.newscientist.com. I've always thought it is part of our nature to regard people who look and act different as "others", that racism or prejudice is a primal instinct that we have to be constantly vigilant against. You only need to observe a football match to see how primal we human beings are.

Quoted from the article:
"Warfare has been with us for at least several tens, if not hundreds, of thousands of years....In fact several fossils of early humans have wounds consistent with warfare."

"Studies suggest that warfare accounts for 10 per cent or more of all male deaths in present-day hunter-gatherers."

"Anthropologist Mark Flinn of the University of Missouri at Columbia found that cricket players on the Caribbean island of Dominica experience a testosterone surge after winning against another village. But this hormonal surge, and presumably the dominant behaviour it prompts, was absent when the men beat a team from their own village..."

"Our warlike past may have given us other gifts, as well. "The interesting thing about war is we're focused on the harm it does," says John Tooby, an evolutionary psychologist at the University of California at Santa Barbara. "But it requires a super-high level of cooperation." And that seems to be a heritage worth hanging on to."

Thanks to zeitgeiber via reddit.