Contested evidence pushes Ardi out of the woods
Alternative analysis moves ancient hominid to the open savanna
By Bruce Bower
An ancient hominid hung out on grassy savannas, not in forests as initially claimed, a new study argues. Whether the species trucked across open savannas has major implications for understanding how and why human ancestors began walking upright, scientists say.
The original discoverers of the species Ardipithecus ramidus disagree with the new study and say that a wide array of findings — including evidence not considered in the new investigation — keeps these hominids in the woods.
When a 4.4 million-year-old partial Ardipithecus skeleton, dubbed Ardi, was first unveiled in October 2009, she was presented as a forest dweller that split time between walking upright and crawling along tree branches (SN: 1/16/10, p. 22). In this scenario, a two-legged gait evolved to support long-distance foraging by males who were seeking to impress potential mates.
In contrast, the new analysis, published in the May 28 Science, supports a longstanding idea that shrinking African forests spawned the evolution of hominids capable of walking across vast savannas.