RESEARCH ARTICLE Obligate Exudativory Characterizes the Diet of the Pygmy Slow Loris Nycticebus pygmaeus CARLY STARR 1 AND K.A.I. NEKARIS 2 * 1 School of Agriculture and Food Science, University of Queensland, Gatton, Queensland, Australia 2 Oxford Brookes University, Nocturnal Primate Research Group, School of Social Sciences and Law, Oxford, United Kingdom Few primate species are known to excavate plant sources to procure exudates and other foods via active gouging. It is now apparent that slow lorises belong to this rare guild of obligate exudativorous primates. We investigate the diet of the pygmy loris (Nycticebus pygmaeus) in a mixed deciduous forest in the Seima Protection Forest, Eastern Cambodia, and attempted to determine the importance of this resource in their diet. Feeding behaviors of six females and seven males were observed using radio‐ tracking to facilitate follows, and nine fecal samples were collected in February–May and January– March in 2008 and 2009 respectively. We observed 168 feeding bouts, during which the animals ate exudates (76); fruits (33); arthropods (27); flower parts (21); fungi (3); parts of bamboo culms (7); and reptiles (1). We filmed 19 bouts of exudativory, and observed animals consuming exudates in an orthograde posture, or standing quadrupedally over the exudate source. Pygmy lorises also gouged bamboo to collect lichen and fungi, or broke open dead culms to access invertebrates. Feeding occurred on terminal tree branches (24), tree trunks (21), bamboo (13), the middle of branches (7), and the undergrowth (1). The fecal samples contained plant parts, small‐sized arthropods (primarily Coleoptera and Lepidoptera), reptile scales, animal bones, and animal hairs. Pygmy slow lorises are morphologically specialized for processing and digesting exudates, displaying small body sizes, specialized dentitions, elongated, and narrow tongues, large caecums, short duodenums, expanded volar pads, and modified hindlimbs. These features, combined with the prevalence of exudates in their diet across seasons, and ill health when exudates are missing from their diet in captivity, points to this species being an obligate exudativore. Am. J. Primatol. 9999:1–8, 2013. © 2013 Wiley Periodicals, Inc. Key words: radio‐tracking; slow loris; gummivory; fallback foods INTRODUCTION Exudates, including gums, and saps, provide a carbohydrate‐rich energy source for those primates able to access and digest them [Heymann & Smith, 1999]. Although saps, the circulating fluids in plants, can be reached without excavation, gum consumption often requires active gouging of the surface of a tree [Bearder & Martin, 1980b; Vinyard et al., 2003]. At least 69 primate species are now known to use exudates, but until recently only five genera (Callithrix, Mico, Cebuella, Phaner, and Euoticus) were known to gouge the surface of trees to obtain exudates [Nash, 1986; Nash & Burrows, 2010; Smith, 2010; Fig. 1]. These taxa are defined as obligate exudativores and exudates comprise 40% or more of their feeding time (hereafter referred to as diet) [Nash & Burrows, 2010]. Morphological special- izations characterizing these primates include modi- fied anterior dentition, small body size, a large caecum and/or colon, a long tongue, and keeled nails [Hladik, 1979]. Nekaris et al. [2010a] suggest that Asian lorises (Nycticebus, Loris) should be added to this list of exudativores given that they possess all but the last of these adaptations. Nekaris et al. [2010a] reviewed field studies of lorises and pottos, and showed that nine species are now known to include exudates in their diet. Whereas, pottos are only known to scrape gum, seven species of Loris and Nycticebus actively gouge for exudates. Loris clearly seems to use exudates as Contract grant sponsor: Leverhulme Trust; contract grant number: RPG‐084. Conflicts of interest: None. Ã Correspondence to: K.A.I. Nekaris, Oxford Brookes University, Nocturnal Primate Research Group, School of Social Sciences and Law, Oxford OX3 0BP, United Kingdom. E‐mail: anekaris@brookes.ac.uk Received 26 August 2012; revised 29 April 2013; revision accepted 4 May 2013 DOI: 10.1002/ajp.22171 Published online XX Month Year in Wiley Online Library (wileyonlinelibrary.com). American Journal of Primatology 9999:1–8 (2013) © 2013 Wiley Periodicals, Inc.