All 36 species of rattlesnakes require shelter of some sort to protect them from predators, temperature extremes and inclement weather. Some species exhibit strong site fidelity, routinely returning to the same hiding spot, while others are nomadic. Rattlesnakes are flexible; they will use whatever hiding spaces are available; rattlesnakes most commonly use burrows, dense vegetation, rock piles and human debris as retreat sites.
Burrows and Tunnels
Burrows and tunnels are excellent retreats for rattlesnakes, but rattlesnakes cannot dig effectively. If they want to live in the cozy confines of a tunnel or burrow, they must steal or share one. Various animals dig burrows and tunnels underground, including small animals like rodents, frogs and crayfish as well as larger animals like turtles, foxes and rabbits. Gopher tortoises (Gopherus polyphemus) of the southeastern coastal plain of the United States often dig very long burrow systems; eastern diamondback rattlesnakes (Crotalus adamanteus) and a variety of other snake species use the burrows for shelter.
Dense Vegetation and Thickets
Dense patches of vegetation protect rattlesnakes from predators and the elements in some habitats. Additionally, rattlesnakes can lie in ambush, ready to strike prey, while hiding in vegetation. Pigmy rattlesnakes (Sistrurus miliarius) often hide under the large fronds of saw palmetto plants. Timber rattlesnakes (Crotalus horridus) hide in dense areas of vegetation during the spring, summer and fall.
In many parts of their range, rattlesnakes inhabit rocky areas. This is especially prevalent among the species of the American Southwest; banded rock (Crotalus lepidus), Panamint (C. stephensi), speckled rock (C. mitchellii) and tiger rattlesnakes (C. tigris) all prefer rocky terrain. Often these rock piles or outcrops are close to hibernation sites, which allow the snakes to meet their needs in smaller geographic areas. Researcher Jerry W. Vincent studied the color variation of banded rock rattlesnakes in 1982. Publishing his results in "Southwestern Naturalist," he found that the snakes varied in color over their range and that each population of snakes matched the color of their local rock substrate. Scientists have documented that the color of black-tailed rattlesnakes (C. molossus) matches that of the rocks in the area.
Human Structures and Debris
Unlike their relatives and fellow pit vipers, the copperheads (Agkistrodon contortrix); rattlesnakes do not often thrive in close association to human development. Despite this, as humans encroach further and further into rattlesnake habitats, some of the snakes are adapting to the human presence. Rattlesnakes sometimes use the areas beneath wood piles, sheds and porches as hiding or foraging spots. Additionally, rattlesnakes often hide under trash or debris in their natural habitat. Rattlesnakes may hide under scrap metal, wooden signs, lumber, carpet or any other flat items they encounter.
Being ectothermic animals, rattlesnakes must hibernate in areas with cold winters; tropical and subtropical species are usually active year-round. Scientists have investigated the denning behavior of timber rattlesnakes thoroughly. In the northern reaches of the snakes’ range, they use deep cracks or fissures in the bedrock to escape freezing temperatures. Finding suitable sites is not easy, and the snakes live only in areas with these hibernacula. Because of the scarcity of sites, timber rattlesnakes often den communally; in exceptional cases, more than 100 snakes may inhabit a single den. Other species, living in areas without such fissures, often use tree stumps or creek-side rock formations to avoid lethal winter temperatures.
- Animal Diversity Web: Crotalus Molossus
- Arizona Game and Fish Department: Arizona Rattlesnakes
- The Southwestern Naturalist: Color Pattern Variation in Crotalus Lepidus Lepidus (Viperidae) in Southwestern Texas; Jerry W. Vincent
- Reptiles and Amphibians of Arizona: Rock Rattlesnake (Crotalus lepidus)
- Reptiles and Amphibians of Arizona: Tiger Rattlesnake (Crotalus tigris)
- CaliforniaHerps.com: Speckled Rattlesnakes Found in California
- Savannah River Ecology Laboratory: Pigmy Rattlesnake (Sistrurus miliarius)
- US Forest Service: Crotalus Horridus
- West Meade Naturalist: Timber Rattlesnake
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