Accurate interpretation of the cause and timing of bone breakage is essential for understanding the archaeological record. However, many variables potentially influencing break morphology have yet to be systematically explored. Focusing primarily on hammerstone breakage, we introduce new analytical methods for comparing fracture angles using the absolute values of the angle from 90°. We systematically control for intrinsic variables such as taxon, skeletal element, limb portion and skeletal age. We also compare experimental assemblages of femora broken by hammerstone and spotted hyena (Crocuta crocuta). We show that fracture angles are influenced by breakage plane, skeletal element and limb portion. While the latter two have been suggested before, this is the first time the differences have been quantified. We suggest that researchers stratify their assemblages by these variables if they are using fracture angles in analyses. At the assemblage level, hyenas created more oblique fracture angles on oblique breaks than did hammerstones.
Bibliographical noteFunding Information:
This work was partially funded by the Department of Anthropology at the University of Minnesota and a National Science Foundation Grant (#1019408) to Martha Tappen. We are grateful to all the students who participated in this project, especially Cassie Clifford, Joel Cramblit, Sommer Osborn, Suzy Reece, Laura Scheid and Jason Zowin. Thanks go to Josh Feinberg for identifying the stone of our anvil and hammerstone. We thank Tim Wild, the numerous zookeepers and Scruffy from the Milwaukee County Zoo. We also thank Scott Salonek and the Elk Marketing Council for providing the whole elk and individual long bone specimens. This work could not have been undertaken without the efforts of John Soderberg and Keith Manthie; and benefitted from discussions with Gil Tostevin and Kieran McNulty. Special thanks are offered to Sanford Weisberg and Baolin Wu for statistics consultation. We are grateful for helpful revisions and suggestions from Aaron Armstrong, Gilliane Monnier, Katherine Erdman and two anonymous reviewers.
© 2017 University of Oxford
- bone breakage
- carnivore and human bone modification
- experimental archaeology