What extant primates eat: a global survey

Primate dietary profiles have been the focus of a vast cumulative effort of observational field studies which now enable an enhanced level of comparative analysis. Attempts to classify dietary strategies into discrete categories inevitably lead to a loss of detail and often overlook geographic, seasonal, and other forms of variation. We review the feeding ecology and major dietary classes for non-human primates worldwide, demonstrating cases of considerable overlap and proposing an alternative approach that acknowledges the blurriness of boundaries along a continuous spectrum of dietary strategies. This view is supported by a case study showing the highly variable degree of frugivory across platyrrhine primates, and a preliminary extension of this approach to primate taxa worldwide. We explore the association between diet and the anatomical constraint of body size, while emphasizing the complex inter-relationships with behavioral, morphological, physiological, and other variables. In developing the continuum concept, a comprehensive synthesis and accompanying database of primate feeding studies and species traits, would help inform models to better understand the multi-dimensional drivers of dietary decisions.