The niche variation hypothesis (NVH) suggests that populations released from competition are able to expand their realized ecological niche (Van valen 1965; Bolnick et al. 2007). This increase in total niche width (TNW) can arise by i) increasing heterogeneity among individuals’ niche through individual specialization, i.e. inter-individual variation in resource use, (IS – Bolnick et al., 2002; 2003) occurring when different individuals of a population use a subset of the population’s resource pool, or ii) by expanding the niche of all individuals within the population (Bolnick et al. 2007). Although several morphological and phenotypical studies have confuted the NVH (e.g. Meiri et al. 2005), there is generally strong support for this hypothesis when behavioural or ecological traits are considered, and in particular when the trophic niche is measured at the individual level (Bolnick et al. 2007; Maldonado et al., 2017). In this study our primary aim is to corroborate the NVH, providing robust evidence for a significant and positive relationship between population TNW and IS in amphibian populations, at a global scale.