Habitat adaptations in the felid forearm

Abstract

Extant cats inhabit different kinds of habitat, for example open landscapes, forests, and rocky mountainous areas. In this study, the radius and ulna of extant felids were investigated to identify ecomorphological adaptations to different habitats. Simple scatter plots and multivariate analyses (factor analysis, discriminant function analysis) revealed two distinct clusters of cats preferring open habitats to cats preferring closed habitats (i.e., forests). We also applied our approach to an existing, large database of extant cats to determine the effect of intraspecific variation on the forearm bones. According to our dataset, cat species adapted to closed habitats have relatively shorter but thicker forearm bones whereas those with longer and slimmer forearms are adapted to open habitats. Cats that inhabit mountainous habitats show no distinct differences in adaptation and plot in one of the other two habitat categories. Overall, the radius measurements are sufficient to distinguish open and forest habitats, but with inclusion of the ulna measurements, the results are more confident. The presented method of using just four measurements of the forearm bones has much potential for application to fossil taxa. We tested the approach for fossil taxa from the Miocene to Pleistocene with the result that most fossil felids were adapted to closed habitats but with some species being adapted to more open intermediate habitats.