Terrestrial locomotion-where do we stand, where are we going? An introduction to the symposium.

Locomotion is fundamental to the survival of many animal species, and terrestrial environments are one of the primary habitats through which a wide range of animals (including humans) must move. Many recent efforts have been made to broaden the approaches and systems used to understand how terrestrial locomotion is executed and modulated. This symposium highlights these efforts and seeks to identify new directions for the study of this diverse behavior. Studies focusing on the structural and functional foundations of terrestrial locomotion, terrestrial locomotor dynamics, and terrestrial locomotor diversity point toward several promising areas for future work. These include: the development, application, and refinement of computational and robotic models; the integration of approaches to clarify which of multiple layers of selection and biological organization influence locomotor performance; increasing the taxonomic, environmental, and behavioral range of study systems to promote new research syntheses and questions; and expansion of studies from laboratory settings to examinations in the field and in the context of ontogenetic and evolutionary time. With new, integrative data from diverse systems in natural settings, new opportunities will emerge for understanding how locomotion contributes to the survival and fitness of terrestrial animals.