The idea that snakes actively dig complex holes in the soil is a common misunderstanding. Snakes are limbless reptiles, and their anatomy is fundamentally different from mammals like badgers or moles, which possess specialized claws and powerful forelimbs for excavation. While many snakes spend significant time beneath the surface, they access and utilize these subterranean spaces based on their physical adaptations and the type of substrate. Understanding the difference between true digging and simply pushing through loose material or using existing structures is key to understanding how these animals interact with their environment.
Clarifying the Myth: Do Snakes Really Dig?
Snakes generally do not possess the anatomical tools required for “true digging,” which involves the complex excavation of tunnels in compacted soil. They lack the limbs and strong claws necessary to displace large amounts of earth and create a self-supporting burrow. The snake body plan is poorly suited for forceful, sustained soil displacement.
The presence of a snake underground reflects a lifestyle known as fossoriality, or adaptation to living beneath the surface. For most species, this means pushing through loose substrates such as leaf litter, sand, or soft soil, rather than constructing a lasting tunnel. If a snake is found in a deep hole, it is typically using a pre-existing cavity or retreat.
Specialized Adaptations for Subterranean Movement
The few species that actively burrow exhibit specialized anatomical features enabling movement through the soil, primarily involving the head and scales. Many true burrowers have a reinforced, akinetic skull, where the bones are tightly fused and less flexible than in surface-dwelling snakes. This adaptation creates a rigid, helmet-like structure capable of withstanding the mechanical stress of pushing through resistance.
The snout is often blunt, pointed, or wedge-shaped, providing a streamlined, low-friction profile for parting the soil. The scales of fossorial species are frequently smaller, smoother, and more polished than their surface-dwelling relatives, which reduces drag and friction. Robust neck musculature provides the power for the initial head thrusts, driving the rigid snout into the earth to exploit weak points in the soil structure.
The True Burrowers: Species That Manipulate Soil
A handful of species are exceptions to the rule, possessing unique modifications that allow them to actively manipulate loose soil or sand. The genus Heterodon, commonly known as Hognose Snakes, are the most recognizable of these true burrowers. They feature a greatly enlarged, upturned rostral scale—the scale at the tip of the snout—that functions like a small shovel.
The Hognose Snake uses this specialized scale with a distinct side-to-side, or “rooting,” motion to push away loose sand and soil. This technique allows them to rapidly bury themselves for protection or to unearth their preferred prey, such as toads, which they often find hiding just beneath the surface. Other species, like the Shield-nosed Cobra (Aspidelaps scutatus), also use a massive rostral scale in a kinetic shoveling motion to quickly create a shallow depression for concealment. Desert-dwelling snakes, such as Sand Boas, use lateral undulations to “swim” just beneath the surface of the sand, completely burying themselves in seconds.
Utilizing Existing Burrows and Retreats
The vast majority of snakes found in holes are simply taking advantage of structures built by other animals or natural geological features. Snakes are highly opportunistic when seeking shelter and readily occupy abandoned burrows of rodents like mice, voles, gophers, or crayfish. These ready-made tunnels offer a perfect microclimate that would be impossible for the snake to create itself.
Using existing burrows serves several biological functions. In hot climates, snakes retreat underground for thermoregulation, escaping lethal surface temperatures to cool down. In temperate zones, burrows extend beneath the frost line, providing a stable, insulated refuge for brumation—the winter dormancy period. These retreats also offer a secure location for shedding their skin (ecdysis), a safe place to lay eggs, and a hidden vantage point for ambushing prey.