Manual and pedal grasping among anurans: a review of relevant concepts with empirical approaches

Abstract

Here we review studies pertaining to the ways in which frogs use their hands and feet for one of the most charismatic skilled abilities: grasping. We highlight the power of different disciplinary approaches to address grasping. In addition, we discuss the utility of incorporating these approaches for the study of grasping in other tetrapod lineages. We discuss concepts that are of relevance for the study of grasping. Additionally, we report on a set of morphological analyses from an empirical perspective based on a sample of frogs, through which we challenge some of the approaches and concepts considered relevant to hand grasping. We conclude that: (1) anurans present the three main grasping types described in humans (power grip, precision grip and intermediate grip); (2) grasping in frogs, although classically associated with an arboreal mode of life, also occurs in the aquatic environment; (3) grasping can be displayed by the hands and feet, and in particular cases even in the same way; (4) short second metacarpals are good indicators of a grasping hand in anurans; and (5) although wide divergence angles between digits typically indicate enhanced grasping abilities, we demonstrate that, for example in pseudines, this is not always the case.