Relative limb strength and locomotion in Homo habilis
Article first published online: 18 AUG 2008
Copyright © 2008 Wiley-Liss, Inc.
American Journal of Physical Anthropology
Volume 138, Issue 1, pages 90–100, January 2009
How to Cite
Ruff, C. (2009), Relative limb strength and locomotion in Homo habilis. Am. J. Phys. Anthropol., 138: 90–100. doi: 10.1002/ajpa.20907
- Issue published online: 1 DEC 2008
- Article first published online: 18 AUG 2008
- Manuscript Accepted: 24 JUN 2008
- Manuscript Received: 25 APR 2008
- Wenner-Gren Foundation for Anthropological Research
- early Homo;
- locomotor behavior;
- bone strength;
The Homo habilis OH 62 partial skeleton has played an important, although controversial role in interpretations of early Homo locomotor behavior. Past interpretive problems stemmed from uncertain bone length estimates and comparisons using external bone breadth proportions, which do not clearly distinguish between modern humans and apes. Here, true cross-sectional bone strength measurements of the OH 62 femur and humerus are compared with those of modern humans and chimpanzees, as well as two early H. erectus specimens—KNM-WT 15000 and KNM-ER 1808. The comparative sections include two locations in the femur and two in the humerus in order to encompass the range of possible section positions in the OH 62 specimens. For each combination of section locations, femoral to humeral strength proportions of OH 62 fall below the 95% confidence interval of modern humans, and for most comparisons, within the 95% confidence interval of chimpanzees. In contrast, the two H. erectus specimens both fall within or even above the modern human distributions. This indicates that load distribution between the limbs, and by implication, locomotor behavior, was significantly different in H. habilis from that of H. erectus and modern humans. When considered with other postcranial evidence, the most likely interpretation is that H. habilis, although bipedal when terrestrial, still engaged in frequent arboreal behavior, while H. erectus was a completely committed terrestrial biped. This adds to the evidence that H. habilis (sensu stricto) and H. erectus represent ecologically distinct, parallel lineages during the early Pleistocene. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc.