INTRODUCTION

There are many reasons to capture your study animals, including marking or radio-collaring individuals (Chapter 10), taking morphological measurements (Chapter 9) and biological sampling (Chapters 1 and 8). For small nocturnal primates, trapping may be the only way to gather data for density estimates (Chapter 6). Furthermore, it is essential for the determination of spatial distribution and social interactions of individuals, as the most effective method uses direct observation of radio-tagged animals (Sterling et al., 2000). Historically, studies in which wild, larger-bodied non-human primates (hereafter called primates in this chapter) are habituated for long-term observation have rarely included capture, perhaps because researchers have been understandably wary of its effects on subsequent behaviour and habituation. However, our survey (Jolly & Phillips-Conroy, 1993; C. J. Jolly and J. E. Phillips-Conroy, unpublished data) of more than 120 studies that combined observation with capture, and which involved about 65 primate species, showed that a careful capture–release programme using trapping will not cause a previously habituated population to change its behaviour towards human observers, and will not be associated with excess mortality or serious injury. Changes in ranging habits caused by baiting and trapping will be temporary at worst, and basic social organisation and structure will not be affected. The survey also showed that trapping has been used most often to catch diurnal–terrestrial and nocturnal–arboreal species. Diurnal–arboreal primates (apart from callitrichines) have generally been captured by darting (Chapter 8), a bias that seems unjustified.