- Rattlesnakes are important members of the natural community. They will not attack, but if disturbed or cornered, they will defend themselves. Reasonable watchfulness should be sufficient to avoid snakebite. Give them distance and respect.
- The Western Diamondback Rattlesnake is a venomous pit viper species found in the United States and Mexico. It is likely responsible for the majority of snakebite fatalities in northern Mexico and the second greatest number in the USA after C. adamanteus.
- The Western Diamondback Rattlesnake, Crotalus atrox, Crotalus comes from the Greek word crotalon meaning a rattle or a little bell; atrox comes from the Latin word atroc which means hideous or savage. The diamondback rattlesnake has one of the most serious bites with the highest fatality rate in North America. The Diamondback is also the heaviest of all poisonous snakes . This rattlesnake is classified among the pit vipers. Vipers have a head broader than their neck, eyes with catlike pupils, and thick bodies.
- The Western Diamondback is a rigid snake and has the reputation of standing its ground . Just like all of the rattlesnakes, this species is venomous. They are not actually prone to attack offensively, but are extremely defensive. This particular snake assumes the threat posture by slightly flattening the body, rolling it together in a spiral , lifting the forebody from the ground into an S-shape, all while keeping the tail raised and the rattle rattling! This snake can lift its forebody up to 80 cm.. in the air .
- The Western Diamondback rattlesnake is a viper, and the vipers have a pair of long hollow fangs in the upper jaw. Their poison is sent out through the two teeth. When the fangs are not being used, they simply fold back into the mouth . Like shark's teeth, the fangs are continually replaced, with new fangs moving into position about every 60 days. The venom is primarily hemotoxic, attacking blood vessels , blood cells and the heart. Snake venoms are derivatives of digestive enzymes and venom injection is as much a process of "tenderizing" the prey as of killing it. Although about a third of time, the snake bites defensively without injecting any venom, a bite by this particular snake is quite serious and potentially dangerous if medical attention is not sought immediately.
- A snake preparing to strike will gather its body into a defensive coil , from which the upper part of the body can be rapidly extended forward. The speed of the strike is too fast to be followed by the human eye. If provoked into striking repeatedly, the snake will begin to tire and move more slowly. The snake need not be in this position to bite, however; it can strike from any angle , even underwater.
- This venomous snake has a pit organ which is in an indentation of the upper jaw between the nostril and the eye. The pit is about 5 mm deep, with an outer and inner chamber separated by a thin membrane . The pits are heat sensing organs that help detect warm blooded prey. Its primary food items are birds and mammals, but it will also eat reptiles and amphibians , invertebrates and an occasional fish.
- The snake adjust its activity periods according to temperature , active during the evening in hot weather and during the day when the weather is cooler.
Click on the language to view common names.
Common Names in English:
Western Diamond-backed Rattlesnake, Western Diamondback Rattlesnake, Westliche Diamantklapperschlange
Common Names in German:
Species Crotalus atrox
The largest rattlesnake in California, and in the West. Heavy-bodied,
, with a thin neck and a large triangular head
Pupils are elliptical
. Sometimes 3, but usually
4 or more small scales occur on top of the head between the supraocular
scales. (The Northern Mojave Rattlesnake has 2 large scales between
the supraocular scales.)
The ground color and the intensity of the pattern are variable, often matching the habitat ; grey, brown, olive, tan, or yellowish. Diamond-shaped blotches on the back are brown or black, with light edges . Broad black and white rings , fairly equal in width , circle a thick tail with a rattle , consisting of loose interlocking segments, at the end. A new rattle segment is added each time the skin is shed. Newborn snakes do not have a rattle - just a single button which does not make a sound . A light stripe extends from behind the eye diagonally to the upper lip in front of the corner of the mouth crossing over the lip. (The posterior light stripe of the Northern Mohave Rattlesnake extends back beyond the corner of the mouth and does not cross the lip.)
A pit viper with pits on the sides of the head which sense heat. These heat sensors help the snake to locate prey by their warmth. Long, hollow, movable fangs connected to venom glands inject a very toxic venom which quickly immobilize the prey. The snake can control the amount of venom injected and the fangs are replaced if broken . Bites on humans are potentially deadly without immediate medical treatment. Even a dead snake can bite and inject venom if the jaws reflexively open when they are touched.
Dry, rocky, shrub
covered terrain where they can conceal themselves.
Inhabits arid and semiarid areas including mountains, deserts, canyons and rocky vegetated foothills, generally less than 1000 ft . elevation (300 m ).
The species' habitat
and semi-arid regions, from
to mountains and from sandy flats to rocky uplands
desert, grassland, shrubland, woodland, open pine forest
and coastal islands (Degenhardt et al.
1996, Tennant 1998,
Werler and Dixon 2000, Stebbins 2003, Campbell and Lamar 2004). In
southeastern Arizona, this snake
is more numerous
in desert scrub
than in semi-desert grassland (Mendelson and Jennings 1992). It hibernates
in rock crevices or cavities or sometimes in animal burrows or under
(Ernst 1992). Hibernation sometimes occurs communally
in brushy upland ridges. A population in southeastern Arizona used
flats but switched to rocky slopes
1995). This primarily terrestrial
snake sometimes climbs into
vegetation or enters water..
List of Habitats:
- 1 Forest
- 1.4 Forest - Temperate
- 2 Savanna
- 2.1 Savanna - Dry
- 3 Shrubland
- 3.5 Shrubland - Subtropical/Tropical Dry
- 4 Grassland
- 4.4 Grassland - Temperate
- 4.5 Grassland - Subtropical/Tropical Dry
- 6 Rocky areas (eg. inland cliffs , mountain peaks)
- 8 Desert
- 8.1 Desert - Hot
- 8.2 Desert - Temperate [more info]
Crotalus atrox will reach its sexual maturity at three years.
Following hibernation, mating will occur in the spring
Live-bearing. Males engage in ritual combat mostly during the breeding season to defend territory. Necks and forebodies are intertwined, with the stronger snake slamming the smaller one to the ground until the weaker snake leaves the area.
The female diamondback is passive during the mating process , while the male snake will crawl in jerks on top of the female snake, all while he is flicking his tongue. He then will jerk the hind portion of his body vigorously, pressing his tail beneath his partner, who in turn will lift her tail. Their cloacas will make contact, and copulation will occur. The gestation period will last for 167 days! The birthing process may last for three to five hours and produce ten to twenty young. The young will puncture their thin egg membranes right before birth and are born alive!
Primarily nocturnal during periods of excessive daytime heat, but also active during daylight when the temperature is more moderate. Not active during cooler periods in Winter. An ambush hunter, it typically sits near the trail of a mammal, waiting for it to pass by, then strikes at and releases the prey . The snake then follows the trail of the envenomated animal and swallows it whole. When alarmed, a rattlesnake shakes its tail back and forth. The movement rubs the rattle segments together producing a buzzing sound which serves as a warning. When disturbed , in self-defense Western Diamond-backs will often aggressively hold their ground , raising the head high in a striking coil with the tail elevated and rattling, and hissing loudly. Juveniles are born with only a silent button at the end of the tail.
- Whittaker & Margulis,1978
- C. Linnaeus, 1758
- (Hatschek, 1888) Cavalier-Smith, 1983
- Grobben, 1908
- (Haeckel, 1874) Cavalier-Smith, 1998
- Bateson, 1885
- Cuvier, 1812
- Jawed Vertebrates
- Goodrich, 1930
- Superorder: Lepidosauria () -
- Infraclass: Lepidosauromorpha ()
- Subclass: Diapsida ()
- Superclass: Tetrapoda () - Goodrich, 1930
- Infraphylum: Gnathostomata () - auct. - Jawed Vertebrates
- Subphylum: Vertebrata () - Cuvier, 1812 - Vertebrates
- Phylum: Chordata () - Bateson, 1885 - Chordates
- Infrakingdom: Chordonia () - (Haeckel, 1874) Cavalier-Smith, 1998
- Branch: Deuterostomia () - Grobben, 1908
- Subkingdom: Bilateria () - (Hatschek, 1888) Cavalier-Smith, 1983
- Kingdom: Animalia () - C. Linnaeus, 1758 - animals
Campbell and TourÉ 1999: 277 • Conocephalus striatulus Duméril and Bibron 1854: 140 • Crotalus atrox — Conant and Collins 1991: 235 • Crotalus atrox — Liner 1994 • Crotalus atrox — Mcdiarmid • Crotalus atrox — Stebbins 1985: 226 • Crotalus confluentus Boulenger 1896 • Crotalus confluentus Say 1823: 48 • Crotalus confluentus — Burt 1935 • Crotalus confluentus — DumÉril and Bibron 1854: 1476 • Crotalus confluentus — TrÉcul 1876: 440 • Falconeria bengalensis Theobald 1868: 37 (Fide Bauer and Das 1999) • Haldea striatula ? Baird and Girard 1853: 122 • Natrix striatulus Merrem 1820: 118
Status: Accepted Name
Comment: Venomous! Crotalus atrox is responsible for most casualties through snakebite in North America.
Similar to and easily confused with the Northern Mohave Rattlesnake, though there is little range overlap in California. Also similar to and easily confused with the Red Diamond Rattlesnake, but in California the ranges of these two snakes barely meet, and the Red Diamond Rattlesnake is typically light reddish brown or red in color. (Ref. 109982)
Members of the genus Crotalus
ZipcodeZoo has pages for 85 species and subspecies in this genus:
C. adamanteus (Eastern Diamond-Backed Rattlesnake) · C. atrox (Western Diamond-Backed Rattlesnake) · C. atrox atrox (Western Diamond-Backed Rattlesnake) · C. basiliscus (Mexican West Coast Rattlesnake) · C. catalinensis (Santa Catalina Island Rattlesnake) · C. cerastes (Sidewinder) · C. cerastes cerastes (Mojave Desert Sidewinder) · C. cerastes cercobombus (Sidewinder) · C. cerastes laterorepens (Colorado Desert Sidewinder) · C. durissus (Aruba Island Rattlesnake) · C. durissus cascavella (Aruba Island Rattlesnake) · C. durissus collilineatus (Aruba Island Rattlesnake) · C. durissus culminatus (Aruba Island Rattlesnake) · C. durissus cumanensis (Aruba Island Rattlesnake) · C. durissus durissus (Aruba Island Rattlesnake) · C. durissus marajoensis (Aruba Island Rattlesnake) · C. durissus ruruima (Aruba Island Rattlesnake) · C. durissus terrificus (South American Rattlesnake) · C. durissus totonacus (Aruba Island Rattlesnake) · C. durissus trigonicus (Aruba Island Rattlesnake) · C. durissus tzabcan (Aruba Island Rattlesnake) · C. enyo (Lower California Rattlesnake) · C. enyo enyo (Lower California Rattlesnake) · C. ericsmithi (Guerreran Long-Tailed Rattlesnake) · C. horridus (Canebrake Rattlesnake) · C. horridus horridus (Timber Rattlesnake (Atricaudatus)) · C. intermedius (Mexican Smallhead Rattlesnake) · C. intermedius intermedius (Mexican Smallhead Rattlesnake) · C. lannomi (Cascabel Cola-Larga De Autl) · C. lepidus (Rock Rattlesnake) · C. lepidus klauberi (Banded Rock Rattlesnake) · C. lepidus lepidus (Mottled Rock Rattlesnake) · C. lepidus maculosus (Rock Rattlesnake) · C. lepidus morulus (Rock Rattlesnake) · C. mitchelli (Mitchelli) · C. mitchellii (Speckled Rattlesnake) · C. mitchellii angelensis (Speckled Rattlesnake) · C. mitchellii mitchellii (Speckled Rattlesnake) · C. mitchellii muertensis (Speckled Rattlesnake) · C. mitchellii pyrrhus (Southwestern Speckled Rattlesnake) · C. mitchellii stephensi (Panamint Rattlesnake) · C. mitchelli pyrrhus (Southwestern Speckled Rattlesnake) · C. molossus (Black-Tailed Rattlesnake) · C. molossus estebanensis (Black-Tailed Rattlesnake) · C. molossus molossus (Black-Tailed Rattlesnake) · C. molossus nigrescens (Black-Tailed Rattlesnake) · C. molossus oaxacus (Black-Tailed Rattlesnake) · C. oreganus (Western Rattlesnake) · C. polystictus (Mexican Lancehead Rattlesnake) · C. pricei (Twin-Spotted Rattlesnake) · C. pricei miquihuanus (Twin-Spotted Rattlesnake) · C. pricei pricei (Twin-Spotted Rattlesnake) · C. pusillus (Tancitaran Dusky Rattlesnake) · C. ravus (Mexican Massasauga) · C. ruber (Red Diamond Rattlesnake) · C. ruber lorenzoensis (Red Diamond Rattlesnake) · C. ruber lucasensis (Red Diamond Rattlesnake) · C. ruber ruber (Red Diamond Rattlesnake) · C. scutulatus (Mohave Rattlesnake) · C. scutulatus salvini (Mojave Rattlesnake) · C. scutulatus scutulatus (Mojave Rattlesnake) · C. stejnegeri (Sinaloan Long-Tailed Rattlesnake) · C. durissus subsp. terrificus (Cascabel Rattlesnake) · C. tigris (Tiger Rattlesnake) · C. tortugensis (Tortuga Island Rattlesnake) · C. transversus (Cross-Banded Mountain Rattlesnake) · C. triseriatus (Queretaran Dusky Rattlesnake (Crotalus T. Aquilus)) · C. triseriatus triseriatus (Central Plateau Dusky Rattlesnake) · C. unicolor (Aruba Island Rattlesnake) · C. vegrandis (Aruba Island Rattlesnake) · C. viridis (Arizona Black Rattlesnake) · C. viridis abyssus (Grand Canyon Rattlesnake) · C. viridis cerberus (Arizona Black Rattlesnake) · C. viridis concolor (Midget Faded Rattlesnake) · C. viridis helleri (Southern Pacific Rattlesnake) · C. viridis lutosus (Great Basin Rattlesnake) · C. viridis nuntius (Hopi Rattlesnake) · C. viridis oreganus (Northern Pacific Rattlesnake) · C. viridis viridis (Prairie Rattlesnake) · C. willardi (New Mexican Ridge-Nosed Rattlesnake) · C. willardi amabilis (Ridge-Nosed Rattlesnake) · C. willardi meridionalis (Ridge-Nosed Rattlesnake) · C. willardi obscurus (Animas Ridge-Nosed Rattlesnake) · C. willardi silus (Ridge-Nosed Rattlesnake) · C. willardi willardi (Arizona Ridgenose Rattlesnake)
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Accessed through GBIF Data Portal February 27, 2008:
- Arizona State University, International Institute for Species Exploration: Arizona State University Amphibian and Reptile Collection
- Borror Laboratory of Bioacoustics
- California Academy of Sciences: CAS Herpetology Collection Catalog
- Carnegie Museums: Amphibians and Reptiles
- Los Angeles County Museum of Natural History: Vertebrate specimens
- Museum of Southwestern Biology, Division of Amphibians and Reptiles: Museum of Southwestern Biology, Division of Amphibians and Reptiles database
- Museum of Vertebrate Zoology: Terrestrial vertebrate specimens
- Sternberg Museum of Natural History: Herp Collection
- Yale University Peabody Museum: Peabody Herp Collection DiGIR provider Service
- Biodiversity Heritage Library NamebankID: 2538209
- Catalogue of Life Accepted Name Code: Rep-1903
- Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 174310
- IUCN ID: 203021
- Natural Heritage Network Species Identifier: ARADE02020
- Zipcode Zoo Species Identifier: 18096