Analysis of the unintentional production of fragments and flakes during nut-cracking by capuchin monkeys in Ubajara National Park, Brazil

• Grant number: 25/03396-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: July 01, 2025
• End date: November 30, 2025
• Field of knowledge: Humanities - Archeology
• Principal Investigator: Astolfo Gomes de Mello Araujo
• Grantee: Gabriela de Oliveira Affonço
• Supervisor: Tomos Sion Hopkins Proffitt
• Host Institution: Museu de Arqueologia e Etnologia (MAE). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Universidade do Algarve (UAlg), Portugal
• Associated to the scholarship: 24/01237-9 - Analysis of the unintentional production of fragments and flakes during the use of lithic tools by capuchin monkeys from two populations, BP.MS

Abstract

Until recently, the ability to produce lithic technology was considered exclusive to the human lineage. Capuchin monkeys (Sapajus libidinosus) in Serra da Capivara National Park intentionally strike stones against each other to obtain silica powder. During this percussive behavior, unintentional flakes are produced. Although monkeys have not been observed using the flakes, they exhibit technological characteristics comparable to those of human-made flakes. This project aims to analyze the unintentional production of fragments and flakes by capuchin monkeys in Ubajara National Park (UNP) during nut-cracking and compare them to the objects unintentionally produced during the stone-on-stone percussion behavior observed in monkeys in Serra da Capivara National Park (SCNP). We collected 336 objects from the surface and within a 40 cm perimeter around 36 anvils. Based on defined use-wear marks, we will distinguish between what can be considered a tool or a tool fragment within the collected material. The selected objects will be classified, analyzed, and compared to those generated during the stone-on-stone percussion behavior at SCNP. We predict that fragments, flakes, and hammerstones used for nut-cracking can be distinguished from the objects produced during stone-on-stone percussion. The comparative study of monkey behavior could help us uncover how different human behaviors may have generated fragments and flakes with distinct characteristics.