American Journal of Primatology 71:1–9 (2009) RESEARCH ARTICLE Exudativory in the Bengal Slow Loris (Nycticebus bengalensis) in Trishna Wildlife Sanctuary, Tripura, Northeast India N. SWAPNA 1,2 , SINDHU RADHAKRISHNA 3 , ATUL K. GUPTA 4 , AND AJITH KUMAR 1,2Ã 1 Post-graduate Program in Wildlife Biology and Conservation, National Centre for Biological Sciences, Bangalore, India 2 Wildlife Conservation Society-India Program, Centre for Wildlife Studies, Bangalore, India 3 National Institute of Advanced Studies, Bangalore, India 4 Department of Forests and Wildlife, Government of Tripura, Aranya Bhavan, Agartala, Tripura, India In this study we estimated the extent of exudativory in Nycticebus bengalensis and examined whether exudates can be considered as fallback foods. This study was carried out in Trishna Wildlife Sanctuary, northeastern India, in winter (December–February) and summer (March and April). We estimated time–activity budget using instantaneous sampling and used continuous focal animal sampling to record all instances and durations of feeding, over a total of 177 hr. Feeding accounted for 22.372.2% of the activity budget, with no seasonal difference. Bengal slow lorises fed on exudates, nectar, fruit, bark, invertebrates and avian eggs. In addition to scraping they also obtained exudates by gouging holes into the bark of trees. In winter, lorises almost exclusively fed on exudates (94.3% of winter feeding time). In summer, exudates (67.3%) and nectar from one species (22.3%) dominated the diet. This study identifies the Bengal slow loris as the most exudativorous loris. Exudates rather than being a staple fallback food, seem to be a preferred, patchily distributed and common food in the diet of the Bengal slow loris. Exudativory in this species is characterized by high selectivity among species and seasonal variation, which may be related to variations in productivity of exudates and their chemical composition. An understanding of these factors is necessary for predicting the response of this species to human disturbance such as logging. This study also underscores the importance of protecting some of the common species such as Terminalia belerica on which the loris feeds during periods of scarcity. Am. J. Primatol. 71:1–9, 2009. r 2009 Wiley-Liss, Inc. Key words: exudates; diet; seasonal variation; preferred foods; fallback foods INTRODUCTION Plant exudates, consisting of gums, saps, resins and latexes, although rich in energy are often difficult to digest [Douglas, 2006; Porter et al., 2009; Waterman, 1984] and are a relatively uncom- mon dietary choice among vertebrates [Nash, 1986]. However, exudates feature in the diets of at least 37 primate species [Vinyard et al., 2003], giving rise to a separate foraging guild that includes some species of Central and South-American callitrichids, African lorisiformes and cercopithecines, Madagascar lemuri- formes and Asian lorisiformes [Garber, 1987; Nash, 1986; Streicher, 2004; Weins et al., 2006]. Within this guild, an important distinction must be made between species that consume exudates as the principal part of their diet and others that do so in lower quantities or only seasonally [Porter et al., 2009]. Primates of the former category, such as marmosets, pygmy marmosets, fork-marked lemurs and needle-clawed bushbabies, display a suite of specialized anatomical adaptations like an enlarged cecum and colon, procumbent lower incisors and pointed, keeled or claw like nails that aid in the procurement and processing of this food resource [Bearder & Martin, 1980; Nash, 1986; Vinyard et al., 2003]. In contrast, other exudate feeders like tamarins, lion tamarins, callimicos, lesser bushba- bies and patas monkeys lack all or some of these morphological specializations and do not gouge holes into tree bark to elicit exudate flow. Instead they feed on exudates that are formed on trees in response to insect damage/natural breakage or from holes gouged by other species [Bearder & Martin, 1980; Heymann & Smith, 1999; Isbell, 1998; Lopes & Ferrari, 1994; Peres, 1989; Porter et al., 2009]. Marshall and Wrangham [2007] posit that morphological adaptations such as those mentioned Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ajp.20760 Received 6 March 2009; revised 29 September 2009; revision accepted 29 September 2009 Contract grant sponsors: Primate Conservation, Inc.; Wildlife Conservation Society-India Program. Ã Correspondence to: Ajith Kumar, National Centre for Biological Sciences, Bangalore 560 065, India. E-mail: ajith@ncbs.res.in r r 2009 Wiley-Liss, Inc.