Western Blind Snake

Scientific Name: Leptotyphlops humilis
Description: 7-16 inches. Slim snake with no neck constriction and a blunt head and tail. Eyes vestigial, appearing as dark spots under the head scales. A tiny spine at tip of tail. Scales shiny and cycloid, not enlarged on the belly. A single scale between the oculars. Purplish, brown, or pink above, with a silvery sheen. Somewhat lighter below—cream, pink, purplish, or light gray.
Habitat: From desert to brush-covered mountain slopes where there is soil suitable for burrowing. Rocky hillsides with patches of loose soil, canyon bottoms or washes near permanent or intermittent streams. Found in beach sand above the high-tide mark. Burrows among the roots of shrubs, beneath rocks, and enters ant nests in search of prey.
Diet: Small insects and their larvae, spiders, millipedes, and centipedes.
Reproduction: 2-6 eggs, laid July-August. Females tend eggs, and may use communal nests. Hatchlings 3 1/2 inches.
Notes: Occasionally crawls exposed on the surface at night, and sometimes can be found by night driving. By day, search crevices and the soil under rock flakes that lie flat on the ground or against boulders, especially where the soil is slightly damp.

Ring-necked Snake

Scientific Name: Diadophis punctatus
Description: 8-30 inches. Slender, olive, brownish, blue-gray, or nearly black snake with a dark head and usually a conspicuous yellow, orange, or cream neck band. Neck band is absent in some populations. Yellow-orange to red below, the red intensifying on underside of tail. Belly usually spotted with black. Rarely, melanistic individuals are found that lack both the neck band and orange ventral color, and have dark crossbars on the belly. Young: Often dark above, sometimes nearly black. Male: Tubercles on scales above the vent (sometimes also present, but less prominent, in female).
Habitat: Moist habitats—woodland, forest, grassland, chaparral, farms, and gardens. In arid West it is restricted to mountains and water courses where it may descend to 2400 feet.
Habits: Secretive. Seldom seen in open. Usually found on the ground under bark, beneath and inside rotting logs, and under stones and boards. When alarmed, this snake coils its tail and turns up the underside of the tail, revealing the bright red color. Rarely attempts to bite when picked up, but will void musk and foul-smelling contents of the cloaca. Partially constricts prey.
Reproduction: 1-2 clutches of 1-10 elongate white or yellowish eggs, laid June-July, often in a communal nest. Young hatch in about 8 weeks. Mature in 2-3 years.
Diet: Salamanders, small frogs, lizards, small snakes, slugs, worms. May be venomous to small animal prey. Rear upper jaw teeth enlarged but not grooved.

Spotted Leaf-nosed Snake

Scientific Name: Phyllorhynchus decurtatus
Description: 12-20 inches. Pale, blotched snake with a blunt snout formed by a much enlarged rostral scale with free edges. Pink, tan, yellowish, or pale gray above, 24-48 brown blotches between the back of the head and the region above the vent. Blotches also extend onto the tail. White below, unmarked. Pupils vertical. Dorsal scales smooth, except occasionally in males. Anal single.
Habitat: Sandy or gravely desert. Creosote bush. Open desert plains.
Habits: Secretive, nocturnal. Burrowing.
Reproduction: Clutch of 2-4 eggs, laid June-July.
Diet: Small lizards, including banded geckos and their eggs.
Notes: Search roads at night after heavy rains; otherwise it is rarely encountered.

Red Racer

P. Cooper

Scientific Name: Masticophis flagellum piceus
Description: 36-102 inches. Coloration highly variable. General tone above is tan, gray, or pink with black crossbars on the neck. Occasional individuals are black. Anal divided. Young: Blotched or crossbanded with dark brown or black on a light brown background. Black neck markings often faint or absent.
Habitat: Desert, prairie, scrubland, juniper-grassland, woodland, thornforest and farmland. Generally avoids dense vegetation. Ground surface may be flat or hilly, sandy or rocky.
Habits: Abroad by day in hot weather even in deserts. Crawls with great speed, often taking refuge in a rodent burrow, among rocks, or the branches of a bush where it may defend itself with spirit, hissing and striking repeatedly, and sometimes approaching aggressively. When caught it usually attempts to bite; large individuals can lacerate the skin.
Reproduction: 4-20 eggs, laid June-July.
Diet: Small mammals, birds and their eggs, lizards, snakes, insects, and carrion.

Striped Whipsnake

P. Cooper

Scientific Name: Mastichophis taeniatus
Description: 36-72 inches. Black, dark brown, or gray above, often with an olive or bluish cast. A cream or white stripe on each side, bisected by a black line. Additional black lines on the lower sides. Yellowish below, grading to white toward the head and coral pink toward the tail. Dorsal scales smooth. Anal divided.
Habitat: Frequents shrublands, grasslands, sagebrush flats, and canyons, pinyon-juniper woodland, and open pine-oak forests. Often attracted to rocky stream courses, permanent and intermittent. Flatlands and mountains. An alert, fast-moving, diurnal snake that seeks shelter in rock outcrops, rodent burrows, and in trees and shrubs.
Reproduction: 3-12 eggs, laid June-July.
Diet: Lizards, snakes, small mammals, young birds and insects.

Sonoran Whipsnake

P. Cooper

Scientific Name: Masticophis bilineatus
Description: 24-67 inches. Olive to light bluish gray above; lighter on rear 2/3 of body. Usually 2 or 3 light-colored stripes on each side, fading toward the tail. Cream below, becoming pale yellow toward tail. Dorsal scales smooth. Chin usually unmarked. Anal divided.
Habitat: Semiarid lower mountain slopes, with growth of grass, saguaro cactus, paloverde, and ocotillo, through chaparral and juniper into the pine-oak belt in the mountains. Attracted to rocky stream courses. Both terrestrial and arboreal, climbing gracefully in bushes and trees.
Reproduction: 6-13 eggs, laid June-July.
Diet: Young birds, lizards, and frogs.

Desert Patch-nosed Snake

Scientific Name: Salvadora hexalepis hexalepis
Description: 20-46 inches. Slender with a broad yellow or beige, dark-bordered middorsal stripe and a large, patchlike rostral. Middorsal stripe usually 3 scales wide.; occasionally faint or obscured by crossbands. Plain white below, sometimes washed with dull orange, especially toward the tail. Top of head gray. Dorsal scales smooth. Anal divided. Male: Keeled scales above vent and at base of tail. Keeling weak or absent in female.
Habitat: Grasslands, chaparral, sagebrush plains, pinyon-juniper woodland, desertscrub. Sandy and rocky areas on the lower slopes of mountains and on low, dry creosote bush plains in the most extreme parts of the desert.
Habits: Diurnal. Crawls rapidly, like a whipsnake. Chiefly ground-dwelling, but occasionally climbs into vegetation.
Reproduction: 4-10 eggs, laid May-August.
Diet: Small mammals, lizards, and reptile eggs.

Sonoran Gopher Snake

P. Cooper

Scientific Name: Pituophis melanoleucus affinis
Description: 36-110 inches. Large yellow or cream-colored snake with black, brown, or reddish brown dorsal blotches, usually more widely spaced on the tail than on the body. Some have reddish orange in the dorsal interspaces between the blotches. Small secondary blotches on the sides. Usually a dark line across the head in front of the eyes and from behind the eye to the angle of the jaw. White to yellowish below, often spotted with black. Striped-unblotched and striped-blotched individuals are found occasionally. Dorsal scales keeled. Anal single.
Habitat: Desert, prairie, brushland, woodland, open coniferous forest, farmland, grassland. Soil varies—sand, loam, rock, or hardpan.
Habits: Good climber and burrower, active chiefly by day except in hot weather. When aroused it hisses loudly and sometimes flattens its head and vibrates its tail. This behavior along with its markings causes these snakes to be mistaken for rattlesnakes and killed.
Reproduction: 1-2 clutches of 2-24 eggs, laid June-August.
Diet: Rodents, rabbits, birds and their eggs, and occasionally lizards and insects. Kills by constriction.

Arizona Glossy Snake

Scientific Name: Arizona elegans noctivaga
Description: 26-70 inches. Looks like a faded Gopher Snake. Light brown, cream, pinkish, or yellowish-gray above, with tan, brown, or gray blotches that are edged with blackish. White or pale buff below, with no markings. Dorsal scales smooth and glossy. Pupils slightly vertical. Anal single.
Habitat: Shrubby to barren desert, sagebrush flats, grassland, chaparral-covered slopes, and woodland. Generally prefers open areas. Ground is often sandy or loamy but some rocks may be present. Excellent burrower.
Habits: Active mostly at night in the West.
Reproduction: 2-23 eggs, laid in summer.
Diet: Lizards, snakes, small mammals.

Green Rat Snake

Scientific Name: Elaphe triaspis
Description: 24-50 inches. Slim, plain green, greenish-gray, or olive snake with unmarked, whitish or cream underparts that are tinged with yellow. Anal divided. Young: Tan above, with brown blotches.
Habitat: Primarily mountains. Wooded, rocky canyon bottoms near streams. Woodland, thornscrub, chaparral. Pine, oak, sycamore, walnut, cottonwood, wild grape, and willow.
Habits: Spends much time during day in trees or shrubs. At night it hides in rock crevices or underground.
Diet: Rodents (woodrats), other small mammals, lizards, and birds.

California Kingsnake

NPS photo

Scientific Name: Lampropeltis getulus californiae
Description: 30-82 inches. Two pattern types—(1) Banded Dark brown or black above with 21-44 white to yellowish dorsal crossbands that extend to or onto the belly. Brown or dusky pigment may be present on bases of the scales of the light crossbands. (2) Striped Dark brown or black above, with a whitish to cream middorsal stripe and lateral stripes. Uniformly dark or light below. Intermediate forms between (1) and (2) are variously striped or crossbanded. Young: Usually patterned like the adult, but in s. Arizona blotched at first, becoming spotted with age.
Habitat: Coniferous forest, woodland, swampland, coastal marshes, river bottoms, farmland, prairie, chaparral, and desert. Often in vicinity or rocky outcrops and clumps of vegetation and under rotting logs, old lumber, and rocks.
Habits: Chiefly terrestrial, but often climbs. Active mostly in the morning and late afternoon but in hot weather abroad at night. Usually gentle but occasionally strikes, hisses, and vibrates its tail. Sometimes rolls into a ball with its head often at the center and everts the lining of its vent.
Reproduction: 2-24 eggs, laid May-August.
Diet: Snakes (including rattlesnakes), lizards, small turtles, reptile eggs, frogs, birds and their eggs, and small mammals.

Sonoran Mountain Kingsnake

Scientific Name: Lampropeltis pyromelana
Description: 18-41 inches. Red-, black-, and white-banded kingsnake with a rather wide, flat head. Amount of red in the black bands varies greatly, forming a wedge on each side or completely splitting the black bands. Sometimes the red forms broad bands that are narrowly bordered by black. Black bands often become narrow or disappear on sides. Pattern on back imperfectly but variously carried onto the belly. Usually half, or less than half of the white body bands are complete across the belly. Snout white, pale yellow, or black flecked with white. Smooth scales. Anal single.
Habitat: Mountain-dweller, ranging from pinyon-juniper woodland and chaparral to pine-fir belt. Shrubland and coniferous forest, often near streams and springs. Usually found in places with rocks, logs, and dense clumps of vegetation—under objects or occasionally exposed.
Reproduction: 3-6 eggs, laid June-July.
Diet: Lizards and probably snakes and small mammals.

Western Long-nosed Snake

Scientific Name: Rhinocheilus lecontei lecontei
Description: 20-41 inches. Slim, speckled snake with black saddles that are flecked with whitish on the sides. Spaces between saddles are cream, yellow, pink, or red, except for a whitish border next to the saddles. Spaces between saddles usually marked with dark flecks on the sides. Belly whitish or yellow, with a few dark spots toward sides. In the more arid parts a contrastingly banded color phase occurs that usually lacks red in the interspaces and has scant black spotting on the sides. Snout long and pointed, and head only slightly wider than neck. Scales smooth. Anal single. Young: Speckling on sides faint or absent.
Habitat: Deserts, prairies, shrubland.
Habits: Crepuscular and nocturnal and likely to be found on roadways at night. When alarmed it may vibrate its tail, write the hind part of its body, and evert its vent lining, releasing blood and feces. A good burrower.
Reproduction: 1-2 clutches of 4-11 eggs, laid June-August.
Diet: Lizards and their eggs, small snakes, small mammals, and occasionally birds. Large prey is killed by constriction.

Checkered Garter Snake

Scientific Name: Thamnophis marcianus
Description: 18-42 inches. Pale snake with a checkered pattern of large squarish black blotches on a brownish yellow, brown, or olive ground color. Cream or white middorsal stripe becomes yellowish toward head. Paired black blotches at back of head. Whitish or yellowish crescent between the dark blotches and corner of mouth. Top of head usually olive. White below, sometimes with a tinge of yellowish, greenish, or a clouding of slaty gray. Scales keeled. Anal single.
Habitat: Ponds, springs, streams, rivers, and irrigation ditches. Pine-oak belt in the mountains.
Reproduction: Live-bearing, 6-18 young, born June-August.
Diet: Fish, frogs, toads, tadpoles, lizards, and invertebrates. Feeds chiefly at night in warmer areas.

Western Black-necked Garter Snake

Scientific Name: Thamnophis cyrtopsis cyrtopsis
Description: 16-43 inches. Whitish or pale yellow middorsal stripe separates 2 large black blotches at the back of the head. Stripe may be orange and wavy in neck region. White crescent occurs between each blotch and corner of mouth. Top of head gray. Side stripe often wavy because of intrusion of bordering black spots. Olive-brown or olive-gray above, with 2 alternating rows of black spots between the stripes; the spots often fade about midbody. Belly light greenish white, bluish white, or brownish. Scales keeled. Anal single.
Habitat: Streams of foothills and mountains. Desert, grassland, mesquite flats, chaparral-covered hillsides, oak woodland, forests of pine and fir. Permanent and intermittent streams, spring seepages, and irrigation canals, but in wet weather may wander far from water.
Reproduction: Live-bearing; 7-25 young, born June-August.
Diet: Frogs, toads, tadpoles, and crustaceans.

Western Ground Snake

NPS photo

Scientific Name: Sonora semiannulata
Description: 8-18 inches. Small, crossbanded, striped or plain-colored snake with a head that is only slightly wider than the neck. Brown, reddish, orange or gray above, lighter on sides. Dorsal pattern varies greatly. Dark crossbands may encircle the body, form saddles on back or be reduced to a single neck band; or they may be entirely absent. Some populations have a broad beige, red, or orange middorsal stripe and greenish gray or bluish gray sides. Plain, crossbanded, and striped individuals sometimes all occur at the same locality. Whitish or yellowish below, unmarked or with dark crossbands. Scales smooth and glossy. Anal divided.
Habitat: Arid and semiarid regions. Soil may be rocky, gravely, or sandy and has some subsurface moisture. River bottoms, desert flats, sand hummocks, and rocky hillsides where there are pockets of loose soil. Vegetation may be scant. Prairies through desert plant communities, thornscrub, pinyon-juniper to the oak-pine zone.
Habits: Secretive, nocturnal.
Reproduction: 4-6 eggs, laid June-August.
Diet: Spiders, scorpions, centipedes, crickets, grasshoppers, and insect larvae. Shallow grooves on outer sides of the rear teeth suggest that these snakes may be venomous, but they are not dangerous to humans.

Colorado Shovel-nosed Snake

Scientific Name: Chionactis occipitalis annulata
Description: 10-17 inches. Dark- and light-banded snake with a shovel-shaped snout, flatter than in most other snakes. Head little wider than neck. Usually fewer than 45 black crossbands which are saddle-like and encircle the body. Ground color is whitish or yellow. Narrow red crossbands present between the black ones. Dorsal scales smooth. Anal divided.
Habitat: Desert. Washes, dunes, sandy flats, loose soil, rocky hillsides. Vegetation usually scant—creosote bush, desert grasses, cactus, or mesquite.
Habits: Burrowing. Nocturnal. Moves quite rapidly through loose sand. Often stays underground during the day.
Reproduction: 2-9 eggs, laid in summer.
Diet: Insects and larvae, spiders, scorpions, centipedes, and buried chrysalids of moths.
Notes: When hunting these snakes on foot, move quickly from bush to bush with light in hand in order to catch them on the surface before they have time to submerge or climb into the lower branches of bushes.

Tucson Shovel-nosed Snake

Scientific Name: Chionactis occipitalis klauberi
Description: 10-17 inches. Dark- and light-banded snake with a shovel-shaped snout, flatter than in most other snakes. Head little wider than neck. Dark brown or black crossbands are saddle-like and encircle the body. Black or brown secondary bands between the primary bands. Ground color is whitish or yellow. Orange or red saddles are sometimes present between the black ones. Dorsal scales smooth. Anal divided.
Habitat: Desert. Washes, dunes, sandy flats, loose soil, rocky hillsides. Vegetation usually scant—creosote bush, desert grasses, cactus, or mesquite.
Habits: Burrowing. Nocturnal. Moves quite rapidly through loose sand. Often stays underground during the day.
Reproduction: 2-9 eggs, laid in summer.
Diet: Insects and larvae, spiders, scorpions, centipedes, and buried chrysalids of moths.
Notes: When hunting these snakes on foot, move quickly from bush to bush with light in hand in order to catch them on the surface before they have time to submerge or climb into the lower branches of bushes.

Variable Sand Snake

Scientific Name: Chilomeniscus cinctus
Description: 7-10 inches. "Sand-swimmer." Head no wider than neck. Snout flat. Eyes small and upturned. Belly angular on each side. Skin appears varnished. Total number of black or dark brown dorsal crossbands varies from 19 to 49; bands on tail usually completely encircle it. Ground color whitish, pale yellow, or reddish orange, sometimes with orange saddles or a continuous area of orange on the back, between the black bands. Belly whitish to dull yellow. Scales smooth. Anal divided.
Habitat: Arid; fine to coarse sand or loamy soil. Seldom emerges on the surface except at night. Open desert, sandy-gravelly washes and arroyos in rocky uplands.
Habits: When they burrow near the surface, the soil collapses behind them to form serpentine furrows that are usually found in sandy areas among bushes.
Diet: Centipedes, sand-burrowing cockroaches, and probably ant pupae and other insects.

Chihuahuan Black-headed Snake

Scientific Name: Tantilla wilcoxi
Description: 7-14 inches. Black cap is bordered by a contrasting broad white collar that crosses tips of parietals. Collar bordered with black. Cap extends on side of head to corner of mouth. Brown above, with dark spots on sides. Scales smooth. Anal divided.
Habitat: Found under rocks, logs, and dead plants (agave, yucca, and sotol) in shaded rocky canyons and on relatively open, sunny, rocky slopes in desert-grassland and evergreen woodland. Extremely rare.

Night Snake

Gary M. Stoltz/USFWS

Scientific Name: Hypsiglena torquata
Description: 12-26 inches. Pale gray, light brown, or beige snake with dark gray or brown blotches on the back and sides, and usually a pair of large dark brown blotches on the neck. Neck blotches vary; they may be connected, sometimes in a group of 3, or absent. A black or dark brown bar behind the eye contrasts with whitish upper labials. Belly yellowish or white. Head usually flat. Pupils vertical. Scales smooth. Anal divided.
Habitat: Grassland, chaparral, sagebrush flats, deserts, woodland, moist mountain meadows, thornscrub, and thornforest. Rocky and sandy areas.
Habits: Nocturnal and crepuscular.
Diet: Lizards, small snakes (blind snakes), frogs, and salamanders, which it subdues by injecting venom with enlarged teeth toward back of upper jaw.
Reproduction: 2-9 eggs, laid April-August.
Notes: Look in crevices and under rocks, boards, dead branches of Joshua trees, mesquite, saguaro, and other litter. Sometimes found on highways at night.
Venomous: Rear-fanged.

Western Lyre Snake

Scientific Name: Trimorphodon biscutatus
Description: 18-47 inches. A "cat-eyed" snake; pupils vertical. Head broad; neck slender. Named for the lyre- or V-shaped mark on top of the head. Light brown to pale gray above, with 34 or fewer brown blotches on back; each blotch roughly hexagonal in shape and split by a pale crossbar. Cream or pale yellow below, often with brown dots scattered on belly. Scales smooth. Anal divided.
Habitat: Rock-dwelling. Lowlands, mesas, and lower mountain slopes. Hides in deep crevices of large rocks often, emerging at night. Desert grassland, creosote-bush desertscrub, chaparral, pinyon-juniper and oak woodland, open coniferous forest, thornscrub, and thornforest.
Reproduction: 7-20 eggs.
Diet: Lizards, birds, small mammals (including bats which are caught at their roosts and immobilized with venom injected by enlarged grooved teeth toward back of upper jaw). Prey may be constricted.
Notes: Search roads in rocky areas at night.
Venomous: Rear-fanged. Little is known about the effect of the venom on humans.

Arizona Coral Snake

Scientific Name: Micruroides euryxanthus euryxanthus
Description: 13-21 inches. Strikingly colored snake with broad, alternating rings of red and black separated by narrower rings of white or yellow. Markings encircle the body, becoming paler on the belly. Head black to behind the eyes. Broad white or yellow band at the back of the head extends across the tips of the parietals. Snout blunt; head and body somewhat flattened. Scales smooth and glossy. Anal divided.
Habitat: Arid and semiarid regions. Thornscrub, brushland, woodland, grassland, farmland. Plains and lower mountain slopes, often among rocks. In Arizona it is most abundant in rocky upland desert, especially along arroyos and river bottoms.
Habits: Secretive, abroad chiefly at night but sometimes encountered in the daytime on overcast days or after rains. Spends much time underground. When disturbed the head may be hidden under coils, the tail elevated and waved with the tip in a tight coil, and the vent lining everted with a popping sound.
Reproduction: 2-3 eggs laid in summer.
Diet: Lizards and snakes, especially blind and ground snakes.
Venomous: Neurotoxic (affects the central nervous system) and highly dangerous.

Northern Black-tailed Rattlesnake

Gary M. Stoltz/USFWS

Scientific Name: Crotalus molossus molossus
Description: 28-49 inches. Tail and sometimes the snout black. Tail sometimes gray with vague rings. Back with black or brown blotches or crossbands of irregular outline, each edged with whitish and having a single or double patch of light scales at the center. Dark markings toward front and middle of back sometimes diamond-shaped. Scales in pattern areas usually one color, not partly dark and light. Ground color cream, yellow, grayish, olive, greenish, or dark rust. Dark individuals occur on dark lava flows. Scales keeled. Young: Dark rings visible on tail.
Habitat: Mountains, rockslides, outcrops, areas near cliffs, and stream courses. Avoids barren desert. Arid tropical scrub and paloverde-cactus-thornbush through chaparral, into the pine-oak belt.
Habits: Abroad both day and night, especially active after warm rains. Usually non-aggressive
Reproduction: Live-bearing; 3-6 young, born in summer.
Diet: Probably eats small mammals.
Notes: If you hear a rattlesnake, stand still until you have located it; avoid jumping and running blindly. Treat a dead rattler with care. People have been bitten by reflex action of the jaws, even of badly mangled specimens.
Venomous

Tiger Rattlesnake

Scientific Name: Crotalus tigris
Description: 18-36 inches. Back with irregular crossbands ("tiger" markings) of gray or brown; composed of dark dots and often with vague borders. Head small, rattle large. Ground color gray, bluish gray, pink, lavender, or buff, becoming pale orange or cream on the sides. Tail rings usually indistinct because of darkened light rings. Scales keeled.
Habitat: Rocky canyons and foothills of desert mountain ranges; arid environments of cactus, mesquite, creosote bush, ocotillo, saguaro, and paloverde on the lower slopes up into the oak belt.
Habits: Active day and night; often abroad after warm rains.
Reproduction: Live-bearing.
Diet: Eats small mammals (kangaroo rats, pocket mice, deer mice, and often woodrats).
Notes: If you hear a rattlesnake, stand still until you have located it; avoid jumping and running blindly. Treat a dead rattler with care. People have been bitten by reflex action of the jaws, even of badly mangled specimens.
Venomous

Arizona Black Rattlesnake

Scientific Name: Crotalus viridis cerberus
Description: Dark gray, olive, brown, or black above, with large dark brown or black blotches that are often separated by light lines. Blotches on sides conspicuous except in dark individuals. Some nearly solid black. Scales keeled.
Habitat: Shrub-covered sand dunes to timberline, from prairies and desert-edge to mountain forests. Rocky outcrops, talus slopes, rocky stream courses, and ledges are favorite places.
Reproduction: Live-bearing; 1-25 young, born August-October.
Diet: Mammals (mice, ground squirrels, rabbits), nestling birds, lizards, snakes, and amphibians.
Notes: If you hear a rattlesnake, stand still until you have located it; avoid jumping and running blindly. Treat a dead rattler with care. People have been bitten by reflex action of the jaws, even of badly mangled specimens.
Venomous

Western Diamondback Rattlesnake

Luther C. Goldman/USFWS

Scientific Name: Crotalus atrox
Description: 30-84 inches. Largest western rattlesnake. Gray, brown, pink, or yellowish above, with light brown to blackish, light-edged, diamond-shaped or hexagonal blotches on the back and fainter smaller blotches on the sides. Markings often indefinite and peppered with small dark spots, giving the snake a speckled or dusty appearance overall. Tail with broad black and white or light gray rings, about equal in width; sometimes called the "coontail" rattler. Light diagonal stripe behind each eye intersects the upper lip well in front of the corner of the mouth. Dorsal scales keeled. Young: Markings more distinct than in adult.
Habitat: Arid and semiarid regions; desert, grassland, shrubland, woodland, open pine forests, rank growth of river bottoms. Sandy flats to rocky upland areas.
Habits: Crepuscular and nocturnal, but also abroad in daytime. One of the most dangerous North American snake, often holding its ground and boldly defending itself when disturbed.
Reproduction: Live-bearing; 4-23 young, born in summer and fall.
Diet: Mammals (rabbits, squirrels, mice, rats), lizards, and birds.
Venomous

Sonoran Sidewinder

P. Cooper

Scientific Name: Crotalus cerastes
Description: 17-33 inches. Sidewise locomotion with the body moving in an S-shaped curve, is characteristic. Back generally pale, harmonizing with background—cream, tan, pink, or gray, patterned with grayish, yellowish-brown, or tan blotches down back. Dark eyestripe. Supraoculars hornlike, pointed, and upturned—sometimes called the "horned rattler." Scales keeled.
Habitat: Desert; usually found in areas of fine windblown sand in the vicinity of rodent burrows (kangaroo rats, etc.). Most common where there are sand hummocks topped with creosote bushes, mesquite, or other desert plants, but it may also occur on windswept flats, barren dunes, hardpan, and rocky hillsides.
Habits: Sidewinding is a rapid form of locomotion and appears to be best suited to open terrain where the broadside movements are unobstructed by rocks and vegetation. Also minimizes slippage on loose soil and heat uptake from hot surfaces because of the greatly reduced contact between the snake's body and the ground. Chiefly nocturnal, usually hiding by day in animal burrows or coiled, camouflaged, in a shallow self-made pit at the base of a shrub. The "horns" seem to act as sunshades and, by reducing glare, may help this snake ambush its prey in daytime from its location beneath a shrub.
Reproduction: Live-bearing; 5-18 young. Born chiefly in fall.
Diet: Pocket mice, kangaroo rats, lizards, occasionally birds.
Notes: Most easily found by tracking or night driving in sandy areas. The track often shows impressions of the belly scutes and consists of a series of parallel J-shaped marks with the hook of the J pointing in the direction of travel.
Venomous

Southwestern Speckled Rattlesnake

Scientific Name: Crotalus mitchellii pyrrhus
Description: 23-52 inches. Color of back varies greatly—white to dark gray or varying shades of pink or orange—and usually harmonizes with background. Dark bands on back, often split by a lighter color. Dark rings on tail. Scales keeled.
Habitat: Rock-dwelling. Occasionally on loose soil or in sandy areas. Sagebrush, creosote bush, succulent desert, thornscrub, chaparral, and pinyon-juniper woodland.
Habits: Alert, nervous snake that holds its ground when cornered.
Reproduction: Live-bearing; 2-11 young, born July-August.
Diet: Small mammals, lizards, and birds.
Venomous

Mojave Green Rattlesnake

P. Cooper

Scientific Name: Crotalus scutulatus
Description: 24-51 inches. Well-defined, light-edged dark gray to brown diamonds, ovals, or hexagons down middle of back; light scales of pattern usually entirely light-colored. Ground color greenish gray, olive green, brownish, or yellowish. White to yellowish stripe extends from behind the eye to a point behind the corner of the mouth. Tail with contrasting light and dark rings; dark rings narrower than light rings. Scales keeled.
Habitat: Upland desert and lower mountain slopes. Barren desert, grassland, open juniper woodland, and scrubland. Most common in areas of scattered scrubby growth such as creosote bush and mesquite. Not common in broken rocky terrain or where vegetation is dense.
Reproduction: Live-bearing; 2-11 young, born July-August.
Diet: Kangaroo rats and other rodents, and probably other reptiles.
Venomous: Extremely virulent neurotoxin affects the heart, skeletal muscles, and neuromuscular junctions. Hemorrhagic toxin is also present. However, two populations in Arizona show a divergence in the toxins: snakes from southeast to northwest Arizona contain only neurotoxins. Snakes from east and northeast of Phoenix south to Tucson contain only hemotoxins.

Sources:

Behler, John L. and F. Wayne King. National Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, Inc. 1996.

Conant, Roger and Joseph T. Collins. A Field Guide to Reptiles and Amphibians of Eastern and Central North America—Third Edition, Expanded. Houghton Mifflin Company. 1998.

Ernst, Carl H. Venomous Reptiles of North America. Smithsonian Institution Press. 1992.

Klauber, Laurence M. Rattlesnakes: Their Habits, Life Histories, and Influence on Mankind. University of California Press. 1982.

Pough, F. Harvey, Robin M. Andrews, John E. Cadle, Martha L. Crump, Alan H. Savitzky, and Kentwood D. Wells. Herpetology. Prentice Hall. 1998.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians—Second Edition. Houghton Mifflin Company. 1985.