Prairie Rattlesnake
Crotalus viridis • Order: Squamata; Suborder: Serpentes; Family: Viperidae; Subfamily: Crotalinae; Genus: Crotalus; Species: Crotalus viridis
Occupies the Great Plains of North America, ranging from southwestern Canada (Alberta, Saskatchewan) through the central United States (including South Dakota, as shown in the image context) down to northern Mexico.
Look up Prairie Rattlesnake in the Snake Encyclopedia →Venomous Status
Venomous (Solenoglyphous; featuring long, hollow, retractable fangs at the front of the mouth).
Danger Level
High Risk; this species is responsible for a significant number of venomous bites in the Great Plains region. While rarely fatal with modern medical treatment, bites can cause severe localized tissue destruction and permanent injury.
Family
Order: Squamata; Suborder: Serpentes; Family: Viperidae; Subfamily: Crotalinae; Genus: Crotalus; Species: Crotalus viridis
Conservation
IUCN Status: Least Concern. However, they face threats from habitat loss, road mortality, and persecution through 'rattlesnake roundups' in certain regions.
Physical Description
Large, triangular-shaped head distinct from the neck. The body is greenish-gray to olive-brown with a series of dark brown, rounded dorsal blotches edged in white. It possesses heat-sensing pits between the eye and nostril, elliptical pupils, heavily keeled scales, and a keratinous rattle at the end of the tail.
Size & Dimensions
The specimen in the image appears to be an adult. Typical adult length ranges from 90 to 120 cm (35–47 inches), with maximum recorded lengths reaching approximately 150 cm (5 feet).
Habitat
Primarily inhabits dry grasslands, prairies, sagebrush flats, and rocky outcrops. They are found from low elevations up to 2,740 meters (9,000 feet) and often utilize rodent burrows for microhabitats and brumation.
Behavior & Temperament
Generally shy but highly defensive when cornered. Defensive behaviors include coiling (as seen in the image), rattling the tail loudly to warn intruders, and striking if the threat persists. Primarily diurnal or crepuscular, becoming nocturnal during extreme summer heat.
Diet & Feeding
Active foragers and ambush predators. Diet consists mainly of small mammals (prairie dogs, ground squirrels, mice), birds, and occasionally lizards. Prey is struck, envenomed, released to die, and then tracked via scent.
Reproduction
Viviparous (gives birth to live young). Breeding occurs in mid-to-late summer, but females store sperm until the following spring. Litters typically range from 4 to 15 neonates born in late summer.
Venom Profile
Complex cocktail primarily composed of hemotoxins and cytotoxins, which cause tissue damage, swelling, and blood-clotting issues. Some populations may also possess neurotoxic components (notably 'Viriditoxin').
Look-alikes
Often confused with the Bullsnake (Pituophis catenifer), which is non-venomous but mimics the rattlesnake's behavior by flattening its head and vibrating its tail. The Bullsnake lacks the rattle and heat-sensing pits, and has round pupils.
Conservation Status
IUCN Status: Least Concern. However, they face threats from habitat loss, road mortality, and persecution through 'rattlesnake roundups' in certain regions.
Cultural Significance
An iconic symbol of the American West. They play a vital ecological role in controlling rodent populations. Indigenous cultures often regard them with a mix of reverence and caution, occasionally featuring them in art and folklore.
Notable Features
Features a highly specialized rattle composed of interlocking keratin segments. They are also known for communal denning, where hundreds of snakes may gather in a single hibernaculum to survive the winter.