Folia Primatologica 0 (2023) 1-14 brill.com/ijfp Regional variation in the behavioral aspects of long-tailed macaques and its ecological determinants Santi Julianti a , Kanthi Arum Widayati a,∗ and Yamato Tsuji b a Department of Biology, IPB University, Jl. Raya Dramaga, Kampus IPB Darmaga Bogor, 16680 West Java, Indonesia b Department of Science and Engineering, Ishinomaki Senshu University, Ishinomaki, 986-8580, Japan * Corresponding author; e-mail: kanthiarum@gmail.com ORCID iD: Widayati: 0000-0002-0536-5100 Received 8 June 2022; accepted 21 December 2022; published online 14 February 2023 Abstract – Dietary composition and activity budgets of primate are affected by habitat characteristics. We described variations in activity budgets and dietary habits of free-ranging long-tailed macaques (Macaca fascicularis) in various habitats, including anthropogenic habitats, through a web-based survey, and tried to find determinants of the regional variation in the behavioral aspects of macaques. The activity budgets of the macaques were stable across sites regardless of geographic, climatic, and anthropogenic characteristics, but dietary composition varied among habitats; the percentage of fruits and seeds was significantly lower at higher latitudes. The plasticity of frugivory in response to regional variations in the food environment was similar to that of macaques inhabiting temperate regions. In habitats with strong human activity, the percentage of anthropogenic foods in the macaque diet was remarkably higher, and fruits and seeds was lower than that in natural habitats. Our results suggested that macaques showed high dietary adaptability to different habitats. Keywords – activity budget, dietary composition, food habit, meta-analysis, regional variation. Introduction Food composition is an important deter- minant of group distribution, social behavior, and foraging behavior in mammals (Clutton- Brock and Harvey, 1978; Robinson and Red- ford, 1986; Gende and Quinn, 2004). Food com- position is affected by food availability, which is related to the geographical and climatic char- acteristics of habitats (Hill and Dunbar, 2002). Feeding efforts indirectly affect the budgets of other activities (Dunbar, 1992). Mammals have evolved behavioral traits under specific habitats, such as searching for alternative foods, expand- ing or shifting home ranges, and using tools for foraging (Pomeroy, 2006; Herzog et al., 2014; Cabana et al., 2016). Comparing behavioral aspects among dif- ferent environments is a suitable approach to address the behavioral adaptation of ani- mals, and a study of regional variation in the diet of Japanese macaques (Macaca fus- cata), for example, found that snow depth is the primary determinant of dietary composition (Tsuji et al., 2015). Wild European cats (Felis silvestris) inhabiting lower latitudes consume more rodents, whereas those inhabiting higher latitudes feed more on rabbits and insectivores (Lozano et al., 2006). Martens (Martes spp.) in the boreal region feed more on rodents, whereas those in the temperate region feed more on fruit (Zhou et al., 2011). Regarding activity, popu- lations inhabiting areas with lower fruit pro- ductivity spend more time feeding (Agetsuma and Nakagawa, 1998; Hill and Dunbar, 2002). Most previous studies on regional variation in behavioral aspects have been conducted in tem- perate regions, and little information has been obtained from the tropics, in which fruit pro- ductivity seems much richer and available for longer periods than in temperate forests (Ting et al., 2008; Moles et al., 2009). © KONINKLIJKE BRILL NV, LEIDEN, 2023 DOI 10.1163/14219980-bja10007 Downloaded from Brill.com03/23/2023 07:50:44AM via free access