Venomous Snakes in Colorado: 3 Species & How to Tell

Habitat: Dry plains grassland and sandhill areas; attracted to sandy soils supporting abundant rodent and lizard populations; hibernates singly in rodent burrows, often in firm, loamy soils adjacent to sandy areas used for feeding. (Colorado Parks and Wildlife)

Venom: “Western Rattlesnake (Midget Faded Rattlesnake)*” (Colorado Parks and Wildlife)

Habitat: Virtually every terrestrial habitat within the geographic and elevational range; sandhills, semidesert shrubland, mountain shrubland, riparian zones, pinyon-juniper woodland, and montane woodland; soils may be sandy to rocky; absent from perennially wet areas and high mountains; basically terrestrial, but sometimes climbs into vegetation or onto rocks or logs. Takes shelter in crevices, woodpiles, brushy vegetation, or mammal burrows. Hibernates in rodent burrows or in crevices in rock outcrops. (Colorado Parks and Wildlife)

Range: Found throughout most of Colorado, except the high mountains, reaching an upper elevational limit of 7,500–9,500 feet in different areas of the state. Fairly common in many areas.

Habitat: Virtually every terrestrial habitat within the broad geographic and elevational range; plains grassland, sandhills, semidesert shrubland, mountain shrubland, riparian zones, pinyon-juniper woodland, and montane woodland; soils may be sandy to rocky; absent from perennially wet areas and high mountains; basically terrestrial, but sometimes climbs into vegetation or onto rocks or logs. Takes shelter in crevices, woodpiles, brushy vegetation, or mammal burrows. Hibernates in rodent burrows or in crevice s in rock outcrops. (Colorado Parks and Wildlife)

Venom: “Like all garter snakes, they are mildly venomous, but are not considered dangerous to humans.” (Colorado Parks and Wildlife)

Range: Known to occur as far north as the Arkansas River valley in southeastern Colorado, in John Brown Canyon in Mesa County in west-central Colorado, and in southern La Plata and Archuleta counties in southwestern Colorado, at elevations below 6,500 feet. Spotty distribution, uncommon.

Habitat: Vicinity o f permanent and intermittent streams, often in canyon bottoms with rocky slopes covered in oak and/or juniper; frequently wanders away from streams, sometimes observed in open grassland, especially near dry washes or at temporary pools used by breeding toads. Takes shelters under rocks or wood, in crevices or burrows, or among exposed streamside tree roots. (Colorado Parks and Wildlife)

Venom: “Otherwise, both snakes are mildly venomous, exclusively nocturnal, and rarely seen.” (Colorado Parks and Wildlife)

Range: Colorado Distribution: Southeastern Colorado, mostly south of the Arkansas River, and west-central Colorado and southwestern Colorado; occurs at elevations below 6,000 feet in the southeast, below 6,600 feet in west-central Colorado, and up to 7,900 feet at Mesa Verde in southwestern Colorado. Secretive, difficult to find, but not necessarily rare.

Habitat: Rocky slopes and canyons sparsely vegetated with piñon-juniper woodland and/or various shrubs and grasses; occasionally found in flat plains grassland far from rocky slopes; a ground-dwelling species that seems to spend most of the time under rocks, in crevices or in rodent burrows; found beneath rocks mainly during the mild weather of spring, late summer, and fall. (Colorado Parks and Wildlife)

Venom: “The common garter snake is mildly venomous, but its venom is considered non-dangerous to humans.” (Colorado Parks and Wildlife)

Range: Northeastern Colorado along the South Platte River and its tributaries at elevations below 6,000 feet and North Fork Republican River drainage in Yuma County at about 3,500–3,600 feet; widely distributed along the eastern base of the Front Range.

Habitat: Marshes, ponds, and the edges of streams; basically restricted to aquatic, wetland, and riparian habitats along the floodplains of streams; seldom found away from water or at isolated ponds. Active in shallow water and on land adjacent to water. (Colorado Parks and Wildlife)

Venom: “Otherwise, both snakes are mildly venomous, exclusively nocturnal, and rarely seen.” (Colorado Parks and Wildlife)

Range: Colorado Distribution: Southeastern Colorado, mostly south of the Arkansas River, and west-central Colorado and southwestern Colorado; occurs at elevations below 6,000 feet in the southeast, below 6,600 feet in west-central Colorado, and up to 7,900 feet at Mesa Verde in southwestern Colorado. Secretive, difficult to find, but not necessarily rare.

Habitat: Rocky slopes and canyons sparsely vegetated with piñon-juniper woodland and/or various shrubs and grasses; occasionally found in flat plains grassland far from rocky slopes; a ground-dwelling species that seems to spend most of the time under rocks, in crevices or in rodent burrows; found beneath rocks mainly during the mild weather of spring, late summer, and fall. (Colorado Parks and Wildlife)

Venom: “Only known to exist in one area of Colorado, the eastern hognose is a mildly-venomous snake that specializes in eating toads.” (Colorado Parks and Wildlife)

Habitat: Typically found in sandy habitats. (Colorado Parks and Wildlife)

Venom: “While they are venomous, they are considered harmless to humans.” (Colorado Parks and Wildlife)

Range: Known from southeastern Colorado, the Republican River drainage in northeastern Colorado, and the eastern margin of the Front Range. Secretive, usually difficult to find, but locally common.

Habitat: Flat plains grassland, sandhills, mountain foothills, and rocky canyons; sometimes can be found in old rubbish dumps. A terrestrial and fossorial species that during daylight hours can be found beneath rocks, wood, dried cow dung, or other debris; in yucca plants; and in rotting logs near streams. (Colorado Parks and Wildlife)

Venom: “While plains garter snakes are venomous, their venom is non-toxic to humans.” (Colorado Parks and Wildlife)

Habitat: Vicinity of virtually any permanent or semipermanent flowing or nonflowing body of water; typically along shores and shallows of marshy areas but often strays far from water, showing up in residential areas, dry grasslands, and sandhills. Seeks shelter underground or beneath rocks, logs, or similar cover. (Colorado Parks and Wildlife)

Venom: “This snake uses its venom to subdue prey, but it is harmless to humans and mammals.” (Colorado Parks and Wildlife)

Habitat: Plains grassland, especially where abundant surface cover is present, and, more often, canyon bottoms or riparian areas; infrequently seen in the open; usually under flat rocks or wood in canyon bottoms. Sometimes several individuals of various ages and either sex aggregate under a single rock or log, especially in spring. (Colorado Parks and Wildlife)

Venom: “It is a rear-fanged, venomous snake, but is considered harmless to humans due to its small size and venom being specialized to arthropods.” (Colorado Parks and Wildlife)

Habitat: Mouths of large canyons in areas dominated by sandy, rock-laden soils and xerophytic shrubs (greasewood, sagebrush, saltbush); narrow bottoms of deep, rocky canyons near streamside cottonwood trees; rocky, shrubby slopes above creeks; under rocks in piñon-juniper woodland; under trash in dumps. (Colorado Parks and Wildlife)

Venom: “Like all garter snakes, they are mildly venomous, but are not considered dangerous to humans.” (Colorado Parks and Wildlife)

Range: Throughout most of Colorado, excluding most of the plains region in the northeastern quarter of the state, usually at elevations below 11,000 feet but has been found higher. Common.

Habitat: Almost any terrestrial or wetland habitat in the vicinity of virtually any flowing or non-flowing body of water; not restricted to riparian-aquatic environments, frequently occupies terrestrial habitats far from water. Activity takes place on the ground, in water, or in low vegetation. (Colorado Parks and Wildlife)

Venom: “This is a rear-fanged snake that is venomous, but it is considered non-dangerous to humans.” (Colorado Parks and Wildlife)

Habitat: Sandhills, plains grassland, and sandy floodplains, often in the vicinity of, or along the margins of, streams, irrigation ditches, and ponds. Active on the ground surface or underground. Periods of inactivity are spent burrowed in the soil, in mammal burrows, or, less commonly, under rocks or debris. (Colorado Parks and Wildlife)