The secret life of a rock-dweller: arboreal acrobatics observed in the European leaf-toed gecko Euleptes europaea

The European leaf toed Gecko, Euleptes europaea, is a strictly nocturnal species endemic to the western Mediterranean and has long been considered a rock-specialist as it is associated with this habitat during its entire daily and life cycle. In this study, we report observations of arboreal behaviour in E. europaea, collected during field research over a 40-year period from across the entire species range. We provide a review of the available information on this topic that contributes to a refined view of the habitat uses and arboreal abilities of this species. Arboreal behaviour in E. europaea was observed throughout the year, across different macrohabitats, on a wide variety of tree, shrub, and bush species, on various parts of the plant (trunk, branches, fronds, twigs, leaves), and at different height from the ground. Remarkably, E. europaea shows an extraordinarily agile arboreal locomotion associated with striking morphological adaptations to an arboreal lifestyle, namely a prehensile tail bearing a terminal adhesive pad that supplements grasping force, an equilibrium asset, and scansor adhesion both in static condition and during escape. We conclude that E. europaea is a climbing gecko (opposed to ground dwelling), occupying both rocky and arboreal microhabitats. While the evolutionary origin and ecological drivers of the arboreal behaviour of E. europaea remains to be fully investigated, this realization has important implications for designing fieldwork research and management strategies for conservation.