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Data from: Foraging mode, relative prey size and diet breadth: a phylogenetically-explicit analysis of snake feeding ecology


Glaudas, Xavier et al. (2019), Data from: Foraging mode, relative prey size and diet breadth: a phylogenetically-explicit analysis of snake feeding ecology, Dryad, Dataset,


1. Foraging modes (ambush vs. active foraging) are often correlated with a suite of morphological, physiological, behavioral and ecological traits known as the adaptive syndrome or syndrome hypothesis. In snakes, an ecological correlate often reported in the literature is that ambush-hunting snakes have a higher relative meal size compared to actively foraging snakes which feed on smaller prey items. This “large meal vs. small meal” feeding hypothesis between ambush and active foragers has become a widely-accepted paradigm of snake feeding ecology, despite the fact that no rigorous meta-analysis has been conducted to support this generalization. 2. We conducted a phylogenetically-explicit meta-analysis, which included ca. 100 species, to test this paradigm of snake feeding ecology. 3. We gathered data on prey size by inducing regurgitation by palpation in free-ranging snakes and by examining the stomach contents of preserved museum specimens. When we found prey, we recorded both snake and prey mass to estimate relative prey mass (prey mass/snake mass). We also reviewed published studies of snake feeding ecology to gather similar information for other species. 4. Ambush and active foragers did not differ in minimum or average meal size but the maximum meal sizes consumed by ambush-foraging snakes were larger than the maximum meal sizes eaten by active foragers. This results in ambush-foraging snakes consuming a significantly wider range of meals sizes, rather than being large meal specialists compared to active foragers. We argue that ambush foragers evolved to be more opportunistic predators because they encounter prey less frequently compared to active foragers. This hypothesis is further supported by the fact that ambush foragers also exhibited marginally wider diet breadths, consuming a broader range of prey types in comparison to active foragers. 5. Our study challenges aspects of the foraging syndrome as it is currently conceived, and our results have important implications for our understanding of how foraging mode has shaped the behavior and physiology of ambush-foraging snakes.

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