Interspecific size regularities in tropical felid assemblages

Summary I extend an earlier analysis of size relationships in Neotropical cats to felid assemblages in tropical Africa and Asia. Jaw length is the size measure, which apparently correlates well with modal prey size. Each assemblage contains two species (convergents) that are indistinguishable in jaw length. When, the convergent species are treated as separate entities, there is little evidence of even ratios, but there is a tendency for ratios to be larger on average than expected by random assembly, especially among the larger species. This tendency may reflect greater prey size variance for the large species or fewer alternatives to prey size as a basis for niche segregation among large species. Extreme evenness in size ratios observed among the larger Neotropical cats is not repeated in the other assemblages. Because demonstration of strong size ratio evenness depends on merging the convergents, the significance of such regularity must await greater knowledge of the habits of the convergent species. Differences between the convergent species in habitat use or predatory behavior are suggested by the fact that in each convergent pair, one species has dappled (striped or spotted) coat coloration and the other a plain coat.