Obligate exudativory characterizes the diet of the pygmy slow loris Nycticebus pygmaeus.

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.