A burrow is a hole or tunnel excavated into the ground by an animal to create a space suitable for habitation, temporary refuge, or as a byproduct of locomotion. Burrows provide a form of shelter against predation and exposure to the elements and can be found in nearly every biome and among various biological interactions. Burrows can be constructed into a wide variety of substrates, and can range in complexity from a simple tube a few centimetres long to a complex network of interconnecting tunnels and chambers hundreds or thousands of metres in total length, such as a well-developed rabbit warren.