It has long been suggested that species might exhibit their highest densities at the centre of their geographic range and decline in density towards their range limits. If true, this pattern would have important implications for ecological theory and for conservation management. However, empirical support for this pattern remains equivocal. Furthermore, most research on this topic has emphasized temperate taxa, as is true of much of ecology. Therefore, we here test for a decline in population density from centre to edge of the geographic range of a tropical taxon, primates. In the literature we found data on 30 species and 27 genera from a total of 115 studies with duration of at least 3 mo. Mixed-effects linear models and Wilcoxon matched-pairs signed-rank tests indicated no centre–edge gradient in primate densities. However, densities were significantly lower in more disturbed sites, independent of position in the geographic range.
