Understanding the processes influencing the distribution and abundance of organisms and their adaptations is a prime goal in ecology (Krebs, 1994). Although a community approach has been applied to primates for some time, most of the comparisons have been regionally restricted (Charles-Dominique, 1977; Struhsaker & Leland, 1979; Gautier-Hion, 1980; MacKinnon & MacKinnon, 1980; Mittermeier & van Roosmalen, 1981; Terborgh, 1983; Ganzhorn, 1989). A more global perspective of primate ecology was initiated in the 1980s with intercontinental comparisons of whole primate communities (Bourlière, 1985; Terborgh & van Schaik, 1987; Reed & Fleagle, 1995; Fleagle & Reed, 1996; Wright, 1997) and comparisons of primate and other mammalian radiations (Smith & Ganzhorn, 1996; Wright, 1996; Emmons, chapter 10, this volume).
In 1996, Fleagle and Reed used multivariate techniques to quantify and visualize a ten-dimensional niche space of primate species from eight different communities. The niche dimensions were based on body mass, activity cycle, locomotion and diet. According to this analysis, primate communities in the Old World show similar ecological diversity and occupy similar space in the ten-dimensional hypervolume, while the neotropical primate communities show lower overall diversity than the communities on other continents. Thus, the ecological space filled by primates in the neotropics is smaller than in other regions due to the lack of folivores, the lack of species with very large body mass, and the lack of a diverse set of nocturnal species among New World primates (Terborgh & van Schaik, 1987; Kappeler & Heymann, 1996; Wright, 1997).