Editing Bipedalism (section)

===Traveling efficiency hypothesis===
An alternative explanation is that the mixture of savanna and scattered forests increased terrestrial travel by proto-humans between clusters of trees, and bipedalism offered greater efficiency for long-distance travel between these clusters than quadrupedalism.<ref>{{Cite journal |vauthors=Isbell LA, Young TP |title=The evolution of bipedalism in hominids and reduced group size in chimpanzees: alternative responses to decreasing resource availability |journal=Journal of Human Evolution |volume=30 |issue=5 |pages=389–397 |doi=10.1006/jhev.1996.0034 |year=1996|bibcode=1996JHumE..30..389I }}</ref><ref>{{Cite book |author1=Lewin, Roger |author2=Swisher, Carl Celso |author3=Curtis, Garniss H. |title=Java man: how two geologists' dramatic discoveries changed our understanding of the evolutionary path to modern humans |publisher=Scribner |location=New York |year=2000 |isbn=978-0-684-80000-4 |url=https://archive.org/details/javamanhowtwogeo00roge}}</ref> In an experiment monitoring chimpanzee metabolic rate via oxygen consumption, it was found that the quadrupedal and bipedal energy costs were very similar, implying that this transition in early ape-like ancestors would not have been very difficult or energetically costing.<ref>{{Cite journal |last1=Pontzer |first1=H. |last2=Raichlen |first2=D. A. |last3=Rodman |first3=P. S. |year=2014 |title=Bipedal and quadrupedal locomotion in chimpanzees |journal=Journal of Human Evolution |volume=66 |pages=64–82| doi=10.1016/j.jhevol.2013.10.002 |pmid=24315239|bibcode=2014JHumE..66...64P }}</ref> This increased travel efficiency is likely to have been selected for as it assisted foraging across widely dispersed resources.