Dating archaeological deposits
They found that the Twa and the Agta hunter-gatherers regularly climbed trees to gather honey, an important element in their diets.
More specifically, they observed that the climbers "walked" up small trees by applying the soles of their feet directly to the trunk and progressing upward, with arms and legs advancing alternately.
It was first discovered by Donald Johanson and colleagues in the Afar region of Ethiopia with the recovery of the partial skeleton of a 3.2 million-year-old specimen they named "Lucy".
The find has represented a possible benchmark in human evolution for decades.
The implications for our possible early human ancestors, such as the species Australopithecus afarensis, are significant.
Four key previously excavated sites will be investigated through full-scale excavation.
To do this successfully, they said, required extreme dorsiflexion, or bending the foot upward toward the shin to a degree not normally possible among most modern humans.
"We hypothesized that a soft-tissue mechanism might enable such extreme dorsiflexion," wrote the authors in their study report.
(Africa) 31 December 2012 The results of recently conducted field studies on modern human groups in the Philippines and Africa are suggesting that humans, among the primates, are not so unique to walking upright as previously thought.
The findings have implications for some of our earliest possible ancestors, including the 3.5 million-year-old species Australopithecus afarensis, thought by many scientists to be the first known possible human predecessor to have forsaken arboreal life in the trees and live a life walking upright (bipedalism) on the ground.