An earlier introduction of bow-and-arrow in southernmost Patagonia? firing experiments, survival curve models, and geometric morphometric methods to evaluate the use of Fell IV points as arrowheads

Abstract

In southernmost continental Patagonia (52º S) the introduction of the bow-and-arrow is traditionally associated with the appearance of the small Fell V or "Ona" points around 700 years ago. Earlier and larger Fell IV or "Patagonian" points were considered spear points. Our study focuses on a firing experiment with replicas of the Fell IV points hafted onto arrows that were repeatedly fired and resharpened until the end of their use-life. After each firing, surface impact (bone or meat), macrofractures, and the need for resharpening were recorded. Additionally, size measurements and plan-view photographs of each point at the beginning and end of the experiment, as well as after each resharpening, were documented to further analysis of size and shape variations. Survival-curve models were used to estimate the probability of point survival based on the number of shots and resharpenings endured. By employing landmark-based geometric morphometrics, blade-shape variations throughout replicas' use-life were compared to Fell IV and V archaeological points morphology. The experimental results exhibited the functional efficiency of Fell IV replicas used as arrowheads, with a variable but extended use-life averaging 21 shots and two resharpenings. Shape similarity is observed in the comparison of both experimental and archaeological point datasets. Therefore, an earlier adoption of bow-and-arrow technology in southernmost continental Patagonia is suggested according to experimental data and shape analysis. This technological innovation might be associated with the macroregional climate variations that affected in different ways the subsistence and settlement patterns of Patagonian human populations during the last ca. 2000 years BP.