Scientists from the CENIEH have published a paper in the Journal of Archaeological Method and Theory in which they analyze experimentally the relationships between the anatomy of the arms and the energy expended during the process of stone tool production
The scientists Ana Mateos and Jesús Rodríguez, of the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), in collaboration with the researcher from Isabel I University, Marcos Terradillos, have just published a pioneering paper in the Journal of Archaeological Method and Theory in which they make the first experimental measurements of the energy cost of stone tool production.
In this paper, entitled “Energy Cost of Stone Knapping", they analyze the relationships between the anatomy of the arms and the energy expenditure during the process of hammering and striking, with the collaboration of nine expert knappers, who manufactured that emblematic tool of the Pleistocene, the handaxe, replicating it three times with two direct percussion techniques: one using a quartzite hammer and the other with a deer antler tine.
As Mateos explains, even though analyses show that this is a physical activity of low intensity, metabolically speaking, the work and effort of the upper body (arms and thorax) are a key factor in human physiology. “We have found that individuals with shorter forearms expend less energy in knapping, and this is explained by the greater lever efficacy of the arm at the moment of striking the blow", she states.
As archaeological references, the handaxes found at the Galería site, in the Sierra de Atapuerca, dated at 250,000 to 500,000 years old, the same raw material and, approximately, the same number of impacts as estimated for the originals, were taken. Thanks to this novel approach to energetics in human populations of the Pleistocene, it has been possible to recreate an activity fundamental to their survival, like the production of lithic tools.
“The differences in energy efficiency between knappers, although small, might have affected the likelihood of survival of an individual, in a Paleolithic context", says Rodríguez.
This work has only been possible thanks to the invaluable collaboration of the expert knappers who prepared the 27 experimental handaxe replicas: Raul López, David Canales, Iván de Pedro, Rodrigo Alcalde, Felipe Cuartero, Andreu Ollé, Josep Mª Vergès and Juan Ignacio Morales.