This project focuses on the evolution of the locomotor system in burrowing limbless tetrapods. These mysterious animals have received surprisingly little scientific attention since the beginning of the 20th century. Although they have no legs, they occupy a wide range of different habitats and show several locomotor modes. Despite the description of a new and unique mode of locomotion in a burrowing caecilian in 1971, the locomotor system of limbless tetrapods has received little attention. Consequently, a lot of questions remain to be answered about the evolution of the movements and the forces used to burrow in limbless vertebrates. To answer some of these questions, I will study the morphology (using μCT-scans, dissections, and geometric morphometrics), the movements of the vertebral column and skin during burrowing under different conditions (soil compactness) and the force generating capacity of representative limbless tetrapods. By considering these data within a comparative framework, I will explore to what degree functional and anatomical traits associated with burrowing are the result of convergent evolution across the different limbless tetrapods clades. That information will finally form the basis for defining structural and mechanical traits that are crucial for designing prototypes to test additional hypotheses on adaptive evolution. In the future, the results of this PhD project may be further explored to design bio-inspired robots with burrowing capacities.