# Identification and quantification of projectile impact marks on bone: new experimental insights using osseous points

## TL;DR

This study examines how to identify and quantify projectile impact marks on bones, using experiments with osseous points to better understand ancient hunting technologies.

## Contribution

The study provides new experimental insights into distinguishing osseous projectile impact marks from lithic ones and addresses their rarity in archaeological records.

## Key findings

- Half of the experimental hits resulted in projectile impact marks (PIM), suggesting these marks may have been common in the past.
- The likelihood of PIM being preserved correlates negatively with the preservation potential of skeletal elements.
- Diagnostic marks that may indicate osseous rather than lithic projectile technology are identified.

## Abstract

Shifts in projectile technology potentially document human evolutionary milestones, such as adaptations for different environments and settlement dynamics. A relatively direct proxy for projectile technology is projectile impact marks (PIM) on archaeological bones. Increasing awareness and publication of experimental data sets have recently led to more identifications of PIM in various contexts, but diagnosing PIM from other types of bone-surface modifications, quantifying them, and inferring point size and material from the bone lesions need more substantiation. Here, we focus on PIM created by osseous projectiles, asking whether these could be effectively identified and separated from lithic-tipped weapons. We further discuss the basic question raised by recent PIM research in zooarchaeology: why PIM evidence is so rare in archaeofaunal assemblages (compared to other human-induced marks), even when they are explicitly sought. We present the experimental results of shooting two ungulate carcasses with bone and antler points, replicating those used in the early Upper Paleolithic of western Eurasia. Half of our hits resulted in PIM, confirming that this modification may have been originally abundant. However, we found that the probability of a skeletal element to be modified with PIM negatively correlates with its preservation potential, and that much of the produced bone damage would not be identifiable in a typical Paleolithic faunal assemblage. This quantification problem still leaves room for an insightful qualitative study of PIM. We complement previous research in presenting several diagnostic marks that retain preservation potential and may be used to suggest osseous, rather than lithic, projectile technology.

The online version contains supplementary material available at 10.1007/s12520-024-01944-3.