jueves, 28 de agosto de 2014

Stone-tipped spears lethal, may indicate early cognitive and social skills


Spears were carefully constructed to measure the same for the controlled experiments. Credit: Jayne Wilkins, Benjamin Schoville, Kyle Brown.

Attaching a stone tip on to a wooden spear shaft was a significant innovation for early modern humans living around 500,000 years ago. However, it was also a costly behavior in terms of time and effort to collect, prepare and assemble the spear. Stone tips break more frequently than wooden spears, requiring more frequent replacement and upkeep, and the fragility of a broken point could necessitate multiple thrusts to an angry animal. So, why did early hunters begin to use stone-tipped spears?

To learn if there was a "wounding" advantage between using a wooden spear or a stone-tipped spear, ASU postdoctoral researcher Jayne Wilkins, doctoral student Benjamin Schoville and coauthor Kyle Brown from the University of Cape Town, conducted controlled experiments using tipped and untipped spear replications, a calibrated crossbow and ballistics gelatin. The experiments looked at the size and shape of the "wound," penetration depth and damage done by extraction of the spear. Wilkins and Schoville are affiliated with the Institute of Human Origins, a research center of the ASU College of Liberal Arts and Sciences in the School of Human Evolution and Social Change. [...] sciencedaily.com / Link 2