Trialling nutrient recommendations for slow lorises (Nycticebus spp.) based on wild feeding ecology
Nycticebus spp. have a morphology and physiology adapted to consume and exploit plant gums as a staple food source (Nekaris, 2014). Their dentition is specialised to incisiform canines to form a tooth comb as well as procumbent tusk like pre‐molars (Kubota & Iwamoto, 1967). They have a long narrow tongue able to lap up gum that has not yet dried or nectar (Coimbra‐Filho & Mittermeier, 1978). Their gastrointestinal tract (GIT) is also described to be specialised, with a wide large intestine and a voluminous caecum, suggesting their capability for fermenting plant structural carbohydrates (Stevens & Hume, 1995). These adaptations are convergent with the gum‐feeding marmosets (Cebuella, Callithrix spp.) (Smith, 2010). Field research also confirms that gum is available all year long and is used as a staple food item for the pygmy slow loris, which spends on average 30% of its foraging time on gum (Nycticebus pygmaeus: Starr & Nekaris, 2013), 66% of foraging time for the greater slow loris (Nycticebus coucang: Wiens, 2002), 96% of foraging time for the Bengal slow loris: (Nycticebus bengalensis: Das, Nekaris, & Bhattacharjee, 2014) and 52% of intake for the Javan slow loris (Nycticebus javanicus: Cabana, Dierenfeld, Wirdateti, Donati, & Nekaris, 2017; Rode‐Margono, Nijman, & Wirdateti, 2014). These primates are kept in captivity as illegal pets, popular within Japan, Russia, Indonesia, Czech Republic and the United States (Nekaris & Jaffe, 2007) and in zoos worldwide as well as Asian rescue and rehabilitation centres. In spite of the evidence for their exudativorous feeding ecology, this has not been represented in their captive husbandry.
Nycticebus primates are found in 79 accredited zoos worldwide (Zoological Inventory Management System, Species 360, USA), most of which are being fed a diet far removed from their wild diet which does not cater to their morphology or physiology (Cabana & Nekaris, 2015; Fitch‐Snyder, Schulze, & Larson, 2001; Fuller, Kuhar, Dennis, & Lukas, 2013). Zoological institutions worldwide primarily feed these gummivores as frugivores with high amounts of fruits and concentrate feeds, and, little if any, gum or insects (Cabana & Nekaris, 2015). However, multiple studies have found a link between diet and health issues including kidney, dental, coat and gastrointestinal problems (Debyser, 1995; Fuller, Lukas, Kuhar, & Dennis, 2014).