Functional efficiency and life history of Late Holocene lithic points from southern Patagonia: An experimental estimation using survival curves models

Abstract

As part of a long-term experimental project aimed at assessing size and shape variations and use life of lithic points as they vary by weapon systems, we report the first results of experiments about functional efficiency and life history of two types of Late Holocene lithic points from southern Patagonia commonly known as Fell, Magallanes or Bird IV and V. Ten replicas of each type were fired to depletion or discard, using a traditional wooden longbow of 43 lb draw weight against a target of cow ribs 10 m away. Each point was measured, weighed and photographed in plan view and 360° before and after each firing to record size and shape variations and obtain 2 and 3D digital models. After every firing the kind of impact (bone or meat), the presence-absence of damage (macrofractures) and presence/absence of damage repair were recorded. We estimated the survival probability of both point types, survival measured as number of shots and resharpenings, and fitted each to survival models. Results indicate significant differences in functional efficiency and life history between types. Type IV points show a longer use-life by number of shots and resharpenings, type V points shorter use-life and higher probability of fracture concentrated on the first firing before being resharpened at least once. Linear regression between the number of shots and the number of resharpenings shows a positive relationship for the two point types, although with a higher resharpening rate for type V. All these differences suggest that under the same conditions of use, expected longevity differs significantly between the types, offering new information to evaluate hunting strategies and comparative advantages in the use of different point classes in southern Patagonia prehistory.