title: Complex processing of prickly pear cactus (Opuntia sp.) by free-ranging long-tailed macaques: preliminary analysis for hierarchical organisation.
abstract: Complex food-processing techniques by gorillas, chimpanzees, and orangutans have allowed comparisons of complex hierarchical cognition between great apes and humans. Here, we analyse preliminary observations of free-ranging long-tailed macaques (Macaca fascicularis) (n = 3) in Thailand processing Opuntia sp. cactus fruits. From our observations, we suggest that there is potential to extend the analyses of hierarchical cognition to Old World monkeys. We found that the macaques used six behavioural sequences to obtain Opuntia fruits, remove irritant hairs from the skin of the fruits, and break open, and consume the fruits, each a unique combination of 17 action elements. Removing irritant hairs involved abrading fruits on a sand or rock substrate, and washing fruit in water. The behavioural sequences that macaques use to process Opuntia potentially show features of hierarchical organisation described in the leaf-processing behaviours of great apes. Our observations highlight the need for closer study of complex food-processing behaviour in monkeys to better understand the organisational capacities involved.
authors.affiliation: Division of Psychology, School of Humaninities and Social Sciences, Nanyang Technological University, Singapore, 637332, Singapore. wytan5@e.ntu.edu.sg.
authors.forename: Amanda W Y
authors.initials: AW
authors.lastname: Tan
authors.affiliation: School of Archaeology, University of Oxford Dyson Perrins Building, South Parks Road, Oxford, OX1 3QY, UK.
authors.forename: Lydia
authors.initials: L
authors.lastname: Luncz
authors.affiliation: School of Archaeology, University of Oxford Dyson Perrins Building, South Parks Road, Oxford, OX1 3QY, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Haslam
authors.affiliation: Primate Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Phyathai Road, Pathumwan, Bangkok, 10330, Thailand.
authors.forename: Suchinda
authors.initials: S
authors.lastname: Malaivijitnond
authors.affiliation: Division of Psychology, School of Humaninities and Social Sciences, Nanyang Technological University, Singapore, 637332, Singapore.|School of Archaeology, University of Oxford Dyson Perrins Building, South Parks Road, Oxford, OX1 3QY, UK.|Primate Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Phyathai Road, Pathumwan, Bangkok, 10330, Thailand.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Gumert
mesh_terms: D000818:Animals; D003071:Cognition; D005247:Feeding Behavior; D005638:Fruit / Q000033:anatomy & histology; D006608:Hierarchy, Social; D058865:Introduced Species; D008252:Macaca fascicularis / Q000502:physiology*; D029747:Opuntia / Q000033:anatomy & histology; D012919:Social Behavior; D013785:Thailand
keywords: Hierarchically organised behaviour; Khao Sam Roi Yot National Park; Macaca fascicularis; Thailand