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Humans
Were Born to Run, Scientists Say Wed
Nov 17, 4:05 PM ET By
Patricia Reaney LONDON
(Reuters) - Humans were born to run and evolved from ape-like creatures into the
way they look today probably because of the need to cover long distances and
compete for food, scientists said on Wednesday. From
tendons and ligaments in the legs and feet that act like springs and skull
features that help prevent overheating, to well-defined buttocks that stabilize
the body, the human anatomy is shaped for running. "We
do it because we are good at it. We enjoy it and we have all kinds of
specializations that permit us to run well," said Daniel Lieberman, a
professor of anthropology at Harvard University in Massachusetts. "There
are all kinds of features that we see in the human body that are critical for
running," he told Reuters. Lieberman
and Dennis Bramble, a biology professor at the University of Utah, studied more
than two dozen traits that increase humans' ability to run. Their research is
reported in the science journal Nature. They
suspect modern humans evolved from their ape-like ancestors about 2 million
years ago so they could hunt and scavenge for food over large distances. But
the development of physical features that enabled humans to run entailed a
trade-off -- the loss of traits that were useful for climbing trees. "We
are very confident that strong selection for running -- which came at the
expense of the historical ability to live in trees -- was instrumental in the
origin of the modern human body form," Bramble said in a statement. AGAINST
THE GRAIN The
conventional theory is that running was a by-product of bipedalism, or the
ability to walk upright on two legs, that evolved in ape-like human ancestors
called Australopithecus at least 4.5 million years ago. But
Lieberman and Bramble argue that it took a few million more years for the
running physique to evolve, so the ability to walk cannot explain the
transition. "There
were 2.5 million to 3 million years of bipedal walking without ever looking like
a human, so is walking going to be what suddenly transforms the hominid
body?" said Bramble. "We're
saying 'no, walking won't do that, but running will."' If
natural selection did not favor running, the scientists believe humans would
still look a lot like apes. "Running
has substantially shaped human evolution. Running made us human -- at least in
the anatomical sense," Bramble added. Among
the features that set humans apart from apes to make them good runners are
longer legs to take longer strides, shorter forearms to enable the upper body to
counterbalance the lower half during running and larger disks which allow for
better shock absorption. Big
buttocks are also important. "Have
you ever looked at an ape? They have no buns," said Bramble. Humans
lean forward when they run and the buttocks "keep you from pitching over on
your nose each time a foot hits the ground," he added.
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