Born to Run

There's a new storm in the ranks of anthropologists who try to understand the long and puzzling history of human evolution by studying fossi...

There8217;s a new storm in the ranks of anthropologists who try to understand the long and puzzling history of human evolution by studying fossil evidence from millions of years ago.

A Utah biologist and a Harvard anthropologist have concluded that a dramatic anatomical shift more than 2 million years ago endowed ancestral members of our human family tree with bodies uniquely adapted for long-distance running 8212;a crucial difference between earlier ape-like relatives and the long-limbed forms that mark us all today.

But other experts insist that the two scientists are completely wrong and that their evidence is far from persuasive.

In a study of African fossils dating back nearly 5 million years, Dennis Bramble of the University of Utah and Daniel Lieberman of Harvard University conclude that the evolutionary change they have discovered led directly from earlier creatures8212;known as the Australopithecines8212;to the emergence of the first members of the genus Homo, the true ancestors of Homo sapiens.

The results of their study are published Thursday in the journal Nature.

The evolutionary shift, Bramble said in an interview, must have given the newly evolved creatures a distinct survival advantage, most probably in scavenging dead animals for meat quickly before other scavengers 8212; hyenas or vultures 8212; could consume the meat. It also helped in escaping their own predators. 8220;Humans are awfully good at running, and they have exceptional endurance,8221; Bramble said, 8220;and they are the only primates that engage in this kind of weird behavior 8212; which is why we asked ourselves how this could have happened.8221;

In fact, Bramble said, humans and their Homo ancestors are by no means well adapted for tree-climbing. The far earlier Australopithecines 8212; with short, blunt legs, wide hips and curved toes 8212; were also bipedal but were adapted primarily for living in trees and for walking only briefly, not striding or running.

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But C. Owen Lovejoy of Kent State University, one of the world8217;s most noted paleoanthropologists, reviewed their evidence point by point and said in an interview: 8220;If an animal becomes a dedicated biped, are we to presume that it would evolve without any escape strategy? How can one even conceive of evolving a 8217;walking8217; strategy that was entirely decoupled from a 8217;running8217; strategy?8221;

However, F. Clark Howell, another noted UC Berkeley paleoanthropologist who has studied hominid fossils for his entire career, called the report by Bramble and Lieberman 8220;very important and very provocative.8221; In an interview, he agreed the report is bound to be controversial 8212; and should prompt many more anthropologists to look even more deeply into the issue.