"These results suggest that habitual climbing by Twa and Agta men changes the muscle architecture associated with ankle dorsiflexion," wrote the authors of the study.
It demonstrated that a foot and ankle bone structure adapted primarily for walking upright on land does not necessarily exclude climbing as a behaviorally habitual means of mobility for survival.
These beds reveal a record of a very important time period (1.79 - 1.15 million years ago), a record that contains evidence of critical changes in the area's fauna, stone tools and climate, such as the disappearance of Homo habilis, a very early hominin and possible human ancestor, and the emergence of Homo erectus, a later hominin considered to be the earliest human ancestor to exit Africa and spread across Eurasia.
The find has represented a possible benchmark in human evolution for decades."These traits are widely interpreted as being functionally incompatible with climbing and thus definitive markers of terrestriality." But now, the research shows that bone structure alone is not an indisputable indicator that an ancient hominid was exclusively terrestrial.Australopithecus afarensis is an extinct hominid that lived between 3.9 and 2.9 million years ago.Recent research at Olduvai has focused primarily on earlier beds, so research on these later beds will likely present new data to consider.Four key previously excavated sites will be investigated through full-scale excavation.