<p>Robots capable of manipulating cohesive materials would be beneficial in a variety of complex construction tasks. To discover principles by which robotic systems can effectively manipulate entangled granular media, we develop a robophysical platform for interaction with media composed of u-shaped particles. This robotic platform uses environmental signals to autonomously coordinate excavation, transport, and deposition of material. We test the effect of material initial conditions by characterizing robot performance in two different material compaction states, and observe as much as a 75% change in transported mass depending on initial material compressive loading. This large difference suggests the functional role that properties such as packing and geometric cohesion play in excavation and manipulation. To better understand these properties, we develop an apparatus for tensile testing of the geometrically cohesive media, which reveals how entangled material strength depends strongly on initial compressive loading. These results rationalize the variation observed in robotic performance and point to future directions for better understanding robotic interaction with entangled materials.</p>