Snakes use shelters, often called dens or hibernacula, for various biological needs. These natural or sometimes man-made structures are important for their survival. Such shelters provide a secure environment, enabling snakes to manage body temperature and find refuge from threats.
The Nature of Snake Shelters
A “den” for a snake is not typically a structure they excavate themselves, unlike the burrows dug by many mammals. Instead, snakes make use of existing natural formations or abandoned structures. They often seek out various locations for shelter.
These include:
Rock crevices and ground fissures
Abandoned burrows of other animals (e.g., rodents, armadillos)
Hollow logs and spaces under tree roots
Dense vegetation
Human-made structures like building foundations or old pipes
These locations offer suitable characteristics. A good snake shelter offers protection from the elements, a stable temperature, and concealment from predators. The availability of these ready-made shelters influences where snake populations can thrive, as they depend on them for survival.
The Purpose of Snake Shelters
Snakes seek out and utilize these shelters for several fundamental biological reasons. A primary purpose is thermoregulation. As ectothermic animals, snakes rely on external sources to regulate their body temperature. Shelters offer stable temperatures, protecting snakes from extreme heat or cold. This maintains their metabolic functions.
Shelters also provide significant protection from predators like birds of prey, larger mammals, and other reptiles. During vulnerable periods like shedding (ecdysis), snakes are less mobile and more exposed, making a secure shelter important. Female snakes also use these locations to lay eggs or give birth, ensuring offspring safety. Some snakes may also use shelters as a base for ambush hunting or resting between foraging activities.
Winter Retreats and Group Living
During colder periods, many snake species enter a state called brumation, which is similar to hibernation in mammals. Brumation involves a period of dormancy where snakes become inactive to conserve energy when temperatures drop and food sources become scarce. Deep, stable dens, often referred to as hibernacula, are important for surviving brumation, as they provide consistent temperatures above freezing.
Many snake species, especially those in temperate regions, exhibit communal denning behavior during brumation. They gather in large numbers to share these deep, secure dens, sometimes with hundreds or even thousands of individuals occupying the same space. Garter snakes are a well-known example of species that engage in extensive communal denning. While snakes do not generate significant body heat, the collective mass within a den can contribute to maintaining a slightly more stable ambient temperature. The shared space also offers collective safety against predators.