Faculty Scholarly Dissemination Grants


Cracking the challenges of extractive foraging: Common marmosets use behavior to augment morphological specializations


Biomedical Sciences


College of Liberal Arts and Sciences

Date Range



Medicine and Health Sciences


Extractive foraging requires animals to overcome the mechanical defenses of foods to obtain nutrition. However, resource extraction may entail distinct mechanical stages that each elicit different selection pressures. We test the hypothesis that tree gouging marmoset monkeys, Callithrix jacchus, preferentially gouge trees with fewer mechanical challenges to extracting exudates by examining three distinct stages of bark removal: 1) indentation, 2) crack initiation, and 3) crack propagation. By surveying trees gouged by wild marmosets in Pernambuco, Brazil, we found that trees with less mechanical challenges to crack initiation were gouged more intensely. Variables related to initial bark indentation and crack propagation showed no relationship to gouging behavior. However, marmoset craniofacial morphology displays specialized features that facilitate indentation and crack propagation during tree gouging, suggesting that marmosets use a combination of behavioral choice and morphological specializations to competently perform each mechanical stage in removing bark. Behavioral preference for less challenging resources likely allows marmosets to reduce costs and potential risks associated with extractive foraging. Our data show that extractive foragers can face a set of complex, distinct mechanical processes during resource acquisition. Understanding how each of these processes limit successful foraging is integral to reconstructing selection pressures and understanding food preferences

Conference Name

Midwest Primate Interest Group

Conference Location

Ames, IA

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