Editorial: Exploring burrowing in biological and robotic systems

downward thrust while minimizing drag on the recovery stroke. Furthermore, the work successfully utilizes granular Resistive Force Theory (RFT) as a reduced-order model, demonstrating how theoretical physics can directly validate bio-inspired mechanical design.The concept of maximizing anisotropy is then elegantly distilled in "Efficient reciprocating burrowing with anisotropic origami feet" (Kim et al., 2023). This paper presents a beautiful, minimalist solution to the locomotion and anchoring problems. Instead of relying on complex, multi-actuator systems, the design uses foldable origami feet that passively induce the necessary anisotropic friction. With a single actuator applying only symmetric linear motion, the robot achieves highly efficient, directed burrowing, validating the power of leveraging smart material mechanics-a key theme from the review papers-to achieve complexity of motion with simplicity of actuation.The narrative culminates by applying these concepts to one of the most extreme environments: submerged granular media. "Burrowing and unburrowing in submerged granular media through fluidization and shapechange" (Nayak et al., 2025) presents a system that addresses the double challenge of both sinking and rising. Drawing inspiration from the razor clam's brilliant strategy, the robotic system employs water-jetbased fluidization for its descent, drastically reducing drag. For the crucial, often-neglected problem of unburrowing (rising), the robot utilizes an untethered, soft, inflatable bladder that undergoes periodic radial expansion, a direct parallel to the soft-robot principles of anchoring and shape-morphing. This work is groundbreaking for applications in marine research, archaeology, and seabed infrastructure.This collection clearly demonstrates that the future of subterranean robotics lies in the symbiotic intersection of biology, material science, and engineering mechanics. These five papers take us from defining the four fundamental challenges and identifying the grand challenges of soft materials to creating specific, highly efficient hardware solutions that leverage anisotropic forces in granular media and fluidization in underwater environments. This Research Topic provides the essential tools, models, and design philosophies to drive the next generation of robust, efficient, and truly autonomous subterranean systems.