Janine Chalk1,2, Barth W Wright3, Peter W Lucas4, Katherine D Schuhmacher5, Erin R Vogel6, Dorothy Fragaszy7, Elisabetta Visalberghi8, Patrícia Izar9, Brian G Richmond10. 1. Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD. 2. Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, GA. 3. Department of Anatomy, Kansas City University of Medicine and Biosciences, Kansas City, MO. 4. Department of Bioclinical Sciences Faculty of Dentistry, Kuwait University, Safat, Kuwait. 5. College of Veterinary Medicine, Cornell University, Ithaca, NY. 6. Department of Anthropology, Rutgers University, New Brunswick, NJ. 7. Department of Psychology, University of Georgia, Athens, GA. 8. Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy. 9. Department of Experimental Psychology, University of São Paulo, São Paulo, Brazil. 10. Anthropology Division, American Museum of Natural History, New York, NY.
Abstract
OBJECTIVES: The diet of tufted capuchins (Sapajus) is characterized by annual or seasonal incorporation of mechanically protected foods. Reliance on these foods raises questions about the dietary strategies of young individuals that lack strength and experience to access these resources. Previous research has demonstrated differences between the feeding competencies of adult and juvenile tufted capuchins. Here we test the hypothesis that, compared to adults, juveniles will process foods with lower toughness and elastic moduli. MATERIALS AND METHODS: We present data on variation in the toughness and elastic modulus of food tissues processed by Sapajus libidinosus during the dry season at Fazenda Boa Vista, Brazil. Food mechanical property data were collected using a portable universal mechanical tester. RESULTS: Results show that food tissues processed by the capuchins showed significant differences in toughness and stiffness. However, we found no relationship between an individual's age and mean or maximum food toughness or elastic modulus, indicating both juvenile and adult S. libidinosus are able to process foods of comparable properties. DISCUSSION: Although it has been suggested that juveniles avoid mechanically protected foods, age-related differences in feeding competence are not solely due to variation in food toughness or stiffness. Other factors related to food type (e.g., learning complex behavioral sequences, achieving manual dexterity, obtaining physical strength to lift stone tools, or recognizing subtle cues about food state) combined with food mechanical properties better explain variation in juvenile feeding competency.
OBJECTIVES: The diet of tufted capuchins (Sapajus) is characterized by annual or seasonal incorporation of mechanically protected foods. Reliance on these foods raises questions about the dietary strategies of young individuals that lack strength and experience to access these resources. Previous research has demonstrated differences between the feeding competencies of adult and juvenile tufted capuchins. Here we test the hypothesis that, compared to adults, juveniles will process foods with lower toughness and elastic moduli. MATERIALS AND METHODS: We present data on variation in the toughness and elastic modulus of food tissues processed by Sapajus libidinosus during the dry season at Fazenda Boa Vista, Brazil. Food mechanical property data were collected using a portable universal mechanical tester. RESULTS: Results show that food tissues processed by the capuchins showed significant differences in toughness and stiffness. However, we found no relationship between an individual's age and mean or maximum food toughness or elastic modulus, indicating both juvenile and adult S. libidinosus are able to process foods of comparable properties. DISCUSSION: Although it has been suggested that juveniles avoid mechanically protected foods, age-related differences in feeding competence are not solely due to variation in food toughness or stiffness. Other factors related to food type (e.g., learning complex behavioral sequences, achieving manual dexterity, obtaining physical strength to lift stone tools, or recognizing subtle cues about food state) combined with food mechanical properties better explain variation in juvenile feeding competency.
Authors: Myra F Laird; Barth W Wright; Annie O Rivera; Mariana Dutra Fogaça; Adam van Casteren; Dorothy M Fragaszy; Patricia Izar; Elisabetta Visalberghi; Robert S Scott; David S Strait; Callum F Ross; Kristin A Wright Journal: Sci Rep Date: 2020-11-30 Impact factor: 4.379