Full text
| |
| Author(s): |
Andrés David Ballesteros Ardila
Total Authors: 1
|
| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Psicologia (IP/SBD) |
| Defense date: | 2015-02-02 |
| Examining board members: |
Briseida Dogo de Resende;
Raphael Moura Cardoso;
Miriam Garcia Mijares
|
| Advisor: | Briseida Dogo de Resende |
| Abstract | |
Evidences point out that capuchin monkeys select stone tools for nut cracking based on the physical characteristics of tools (material, weight, transporting distance) in relation to their own physical characteristics (size, weight), and that selectivity seems to affect the efficiency of nut cracking, determining individual decision making in tool use. Considering the prediction that nut crack efficiency is affected by individual control, the stone and the impact angle; this study aimed to evaluate experimentally if the tools shape affect nut crack efficiency, and if this is considered in individual tool selection. We tested the choices of five semi-free individuals using artificial designed tools in eight different experimental conditions, manipulating hammers weight, shape and distance to the anvil, to determine the factors involved in tool selection process for nut cracking. The results shows the monkeys prefer hammers that increase cracking nut efficiency, with more holding possibility, and higher potential contact surface in the bites. There was no evidence for effect of variables related with costs (hammer weight and transporting distance) on the shape preference, and there was no relation between preferences in experimental conditions and engage or efficiency in baseline. We found that the capuchin monkeys based their tool choices in visual characteristics and exhibit manipulative exploratory behaviors that allow them to gain information about the tools shape to make choices (AU) | |
| FAPESP's process: | 13/11158-4 - Stone tool selectivity in capuchin monkeys: tool shape effects |
| Grantee: | Andrés David Ballesteros Ardila |
| Support Opportunities: | Scholarships in Brazil - Master |