A common question arises about whether snakes are responsible for the various holes found in the ground. Understanding the true nature of snake behavior regarding burrows can clarify this widespread inquiry.
The Truth About Snake Digging
Most snakes do not actively dig or create their own burrows. Instead, they are opportunistic, primarily utilizing existing structures for shelter. These structures often include abandoned burrows dug by other animals like rodents, chipmunks, gophers, or tortoises. Snakes lack the limbs or specialized digging tools that would allow them to excavate distinct holes in the way a mammal might.
There are exceptions, however, certain fossorial (burrowing) snake species have adaptations that allow them to move through loose soil or sand. Examples include sand boas, woma pythons, and some species of earth snakes and blind snakes. These snakes typically have pointed snouts and small heads, which help them push through soft substrates rather than actively digging large, open burrows. Even these species rarely create the prominent holes people typically associate with burrowing animals.
Reasons Snakes Utilize Burrows
Snakes use pre-existing holes, crevices, or burrows for several ecological reasons. These underground retreats offer shelter and protection from predators, which is a primary concern for many snake species. They also provide safety from environmental dangers.
Burrows are important for thermoregulation. As ectothermic animals, snakes rely on external sources of heat, and burrows offer stable temperatures—cooler than the surface during hot days and warmer during cold nights. Snakes can move deeper into a burrow to cool down or closer to the entrance to warm up, maintaining a preferred thermal range. During colder periods, many temperate snake species retreat to burrows or rock crevices below the frost line to brumate, a dormant state (brumation) where their metabolism slows, helping them survive.
Some snakes also use burrows for hunting, ambushing prey from a concealed position. The confined space can be advantageous for surprising small animals. Burrows also serve as safe places for reproduction, with many oviparous (egg-laying) snakes depositing their eggs in hollow logs or underground burrows. King cobras are a notable exception, known to construct elaborate nests of leaves and debris for their eggs.
How to Identify a Snake-Used Burrow
Identifying a snake-used burrow involves observing specific characteristics. Snakes typically use holes just large enough for their body, ranging from about half an inch to three inches in diameter. These holes often have smooth edges, as snakes slide in and out without disturbing the surrounding soil, unlike rodent holes with jagged edges or fresh piles of excavated dirt. Snakes also prefer sheltered locations, such as under rocks, logs, dense vegetation, or near home foundations and sheds.
A strong indicator of snake presence is the discovery of shed skin near a hole. Snakes shed their entire outer layer of skin periodically as they grow and to remove parasites, often leaving it in one piece near their retreat. While less common and often subtle, very faint, wavy, S-shaped tracks might be visible in soft earth leading to or from the opening. The absence of distinct paw prints, rodent droppings, or nesting debris like shredded plastic or fabric, which are typical signs of other burrowing animals, also suggests a snake might be the occupant.