Digging tunnels is a normal behavior of groundhogs. They use their snouts to dig tunnels under fences, basements, porches and other places where they feel comfortable. They are not digging tunnels to escape predators, but they might use them as escape routes when they feel threatened.
Groundhogs are herbivores, so they eat mostly plants. The main food source of groundhogs are roots, grasses and other underground plants.