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To: Knighty Tin who wrote (298046)	11/19/2004 9:35:42 AM
From: Pogeu Mahone	Read Replies (1) \| Respond to of 436258

Running was a key human characteristic By SCRIPPS HOWARD . By Lee Bowman . The ability to run long distances across the African savannah gave human ancestors an evolutionary advantage over other primates that walked upright, but could not run the mile or 20, researchers argue in a new study. . “We think running is one of the most transforming events in human history. We are arguing that the emergence of humans is tied to the evolution of running,” said University of Utah biologist Dennis Bramble, co-author with Harvard University anthropologist Daniel Lieberman of the report published Thursday in the journal Nature. . Their argument, built on a detailed examination of 26 traits of the human body, runs against the most prevalent theory that running was simply the ability to walk upright faster. Since human ancestors had been upright on two legs for at least 3 million years before the first member of the “homo” family arose some 2.6 million years ago, there was nothing special about running, conventional wisdom holds. . But Lieberman and Bramble spell out the evolution of traits such as a small ridge at the base of the human skull that helps keep the head steady, shoulders decoupled from our heads, a network of springy tendons along the backs of our legs, taller bodies along with shorter forearms, that all contribute to an ability to run well for a long time, at least compared to apes and monkeys and even to other carnivores and prey. . “These esoteric anatomical features make humans surprisingly good runners. Over long distances, we can outrun our dogs and give many horses a good race,” Lieberman said. . Another distinctive human feature shared by no other primate is the gluteus maximus muscle that makes up the buttocks. Bones of earlier human ancestors and chimps show the ability to support only modest hindquarters. . The buttock muscles “stabilize your trunk as you lean forward to run. A run is like a controlled fall, and the buttocks help to control it,” Lieberman said. . “What these features and fossil facts appear to be telling us is that running evolved in order for our direct ancestors to compete with other carnivores for access to the protein needed to grow the big brains that we enjoy today.” . Endurance running may have helped early humans chase down game and kill it with rocks, stone knives or spears, or simply allowed them to reach carcasses before competing animals did, the researchers suggest. . “Today, endurance running is primarily a form of exercise and recreation, but its roots may be as ancient as the origin of the human genus.” . Bramble noted that many of the physical changes needed for efficient running “came at the expense of the historical ability to live in trees” since human ancestors lost the head-and-shoulder structures that allow chimps — and also the human ancestor australopithecines — to easily climb trees and swing from branches. . Fossil evidence for early humans is incomplete — no one has found the feet from a Homo erectus, for instance — but the trends show all the features related to running emerged at roughly the same time and before human brains began to dramatically increase in volume. . Other scientists working over the past few decades have concluded that the climate of sub-tropical Africa was cooling and becoming drier when the first human ancestors emerged there. The environment shifted from heavily wooded tropical forest to the more open grasslands and herds of grazing animals that are still prevalent today. . Out on the savannah, in a hunter-gatherer clan, simply being able to “get to the leftovers soon enough” might have made the difference in survival, Bramble said. “High speed is not always important. What is important is combining reasonable speed with exceptional endurance.” . On the Net: www.nature.com . (Contact Lee Bowman at BowmanL(at)shns.com or online at shns.com)