Navigating the night: spatial cognition, locomotor and ranging behaviour in Nycticebus species

In this thesis I examined the various ways physical, social, cognitive, and evolutionary factors influence ranging behaviour and spacing in Nycticebus species. I explored these topics with the ultimate goal of informing future conservation actions throughout Southeast Asia, especially translocations and in-situ rehabilitation. Each chapter covers topics, comprising ranging and locomotor behaviour, physical ontogeny, spatial cognition, and sociality. I worked at two field sites between 2014 and 2015 in Java and Vietnam, focused on two species of slow lorises (Nycticebus javanicus ,13 ind. and N. pygmaeus, 6 ind.); augmenting this work with data from long-term datasets and data from existing literature. Despite its frequent use, translocation can have a low success rate in Nycticebus species. I found that home range sizes in translocated pygmy slow loris males were larger than those reported both in wild and other translocated pygmy slow lorises, causing subsequent males to leave the release site. As a natural proxy for human-mediated translocations I analysed long-term data on natal dispersal in the Javan slow loris. I found that both males and females disperse as late as two years after birth. Offspring development and dispersal is rooted in the social interactions between family group members. The skills they acquire during this time help them to find and establish a suitable home range; skills like accessing essential food resources. In the Javan slow loris, I looked at exudate feeding to assess their preparedness. While examining the behavioural repertoire used to access tree gums and the ontogenetic development of the postures needed to access them physically, I found that the Javan slow loris acquires rapidly adult-like limb proportions to help employ vertical postures while feeding on gums highlighting their specialization for vertical clinging. The demand on individuals to locate these resources may act as an important selection pressure on the evolution of spatial cognition. I identified the use of spatial cognition and cognitive maps as tools to revisit goal locations. The distribution of stable resources throughout a home range help individuals create a map of 4 their environment. Another factor affecting spacing and ranging is their social interactions. To reconstruct the ancestral state of primate social organisation in primates, I found that among lorisiforms the presumed promiscuous ancestral state in mammals, then evolved into a dispersed family group at the last common ancestor of lorisiforms. In conclusion, these new data bring to light the difficulties in carrying out a successful translocation, a previously overlooked social dynamic within Nycticebus family groups, the importance of limb proportion in development and vertical clinging, how gum producing trees shape nightly movement, and the evolutionary history of lorisiforms social organizations. This information can be used to formulate new conservation strategies and help refine existing efforts in-situ and in captivity. Especially in translocations, which should amend practices to incorporating the complex sociality and use of spatial cognition to support natural behaviours prior to and throughout the release process