Emergent technological variation in archaeological landscapes: a primate perspective

Abstract

Archaeological evidence informs our understanding of the evolution of hominin behaviour. Such evidence is traditionally used to reconstruct hominin activities and intentions. In the Plio-Pleistocene, the presence or absence of specific tools and variation in artefact density is often used to infer foraging strategies, cognitive traits and functional activities. However, the Plio-Pleistocene archaeological record is known to be time-averaged and forms through the aggregation of repeated behavioural events over time. Thus, archaeological patterns do not reflect discrete episodes of activity, but rather the interaction of behaviour with environmental factors over time. However, little is known about how such interactions produce archaeological variation diversity. Primate archaeology can help address this research gap by providing the opportunity to observe how behaviour produces material patterns in a natural setting. This study, thus, examines how varying the material properties of stone and resource availability influence the artefactual signature of nut-cracking in a population of long-tailed macaques from Lobi Bay, Yao Noi island, Thailand. Results show that these interactions can produce a structured and diverse material signature in terms of artefact density and frequency of specific artefact types. These findings demonstrate how material patterns can emerge from long-term interactions between behaviour and environmental factors.

Keywords: long-tailed macaques; percussive technology; primate archaeology.

Figure 1.

Map showing the geographical context of Ao Lobi Bay plantation (ALP). This map was produced using the package ggmap in R v. 3.04 [67]. Insets: (a) An example of a long-tailed macaque cracking nuts with a stone hammer and anvil. (b) An example of how identifiable palm trees are from aerial imagery of the forest canopy. (c) Example of a nut-cracking site comprising primarily low-quality (red-oxidized limestone) material. The soft nature and presence of internal fracture planes produce angular debris. (d) Example of a nut-cracking site comprising high-quality (grey limestone) material. (e) Example a semi-exposed limestone boulder used as an anvil.

Figure 2.

Maps showing locations of sampled materials. (a) Locations of documented nut-cracking sites across the study area. (b) Location of palm trees across the study area. (c) Map of stratified random sampling strategy and locations of sampled nut-cracking sites. All maps were produced using ggmap in R v3.04 [67].

Figure 3.

Examples of lithic materials associated with each raw material type. (a–d) Light grey limestone; (e–h) red-oxidized limestone. (a) A light grey limestone hammerstone showing signs of battering and negatives associated with conchoidal fracture. (b) A hammerstone fragment bearing traces of battering and previous scar removals. (c,d) Examples of flakes detached during nut-cracking events. (e) Red-oxidized limestone hammerstone. (f) Example of an angular fragment associated with nut cracking. (g) An angular fragment bearing traces of battering due to nut cracking.

Figure 4.

Spatial distribution of raw materials and palm trees. Left: kriging interpolated map comparing the distribution of high- and low-quality limestone across the study area with the proportion of high-quality material within each sampled nut-cracking assemblage. Each point represents a sampled nut-cracking assemblage. Right: kernel density map comparing the density of palm trees across the study area with the total number of artefacts documented at each sample location.

Figure 5.

The influence of hardness on the representation of flakes and flaked pieces.