[george76]

"early human tribes to expand more quickly than their largely vegetarian contemporaries..."

[Varda]

This Pleistocene "vegetarian contemporaries" idea is a PETA induced fantasy. Trust a British paper to include it in a science story.

Clue to the Times,
"Humans evolved beyond their vegetarian roots and became meat-eaters at the dawn of the genus Homo, around 2.5 million years ago, according to a study of our ancestors' teeth."
(http://www.newscientist.com/article.ns?id=dn4122)