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Rattlesnakes are a group of venomous New World snakes, genera Crotalus and
Sistrurus, which have a small noise-making jointed rattle on their tails. If not surprised, they will usually use this rattle as a warning device
when they feel threatened. There are about 30 species, with numerous subspecies.
Rattlesnakes are pit vipers. Pit vipers have heat-sensitive pits between the
eye and the nostril that enable them to find prey very effectively. Pit vipers also have fangs in the upper part of the mouth that fold in when not in use. When a pit viper attacks, it unfolds the fangs,
bites, and injects its venom.
Rattlesnake bites are generally not fatal for adult humans, if promptly and properly treated. Most (but not all) rattlesnake
venom is primarily hemotoxic, meaning it destroys blood cells and other tissue and is often very painful. Permanent damage, including loss of an affected
limb, is possible, even with prompt, effective treatment - a rattlesnake bite is always a potential serious injury.
Some rattlesnakes, especially the tropical species, have primarily neurotoxic venom. A bite from these snakes may not be very painful, but the venom can interfere with the
function of the heart, and can paralyze the lungs. Prompt treatment is essential for any victim of a rattlesnake bite.
Different species of rattlesnake vary significantly with respect to temperament. Some are relatively docile, while some are
quite aggressive when challenged. Rattlesnakes control the amount of venom they inject, generally delivering a full dose to prey,
but less or none when biting defensively. A very significant exception to this is a provoked, enraged snake, which might not only
deliver a full dose, but which may try to do so repeatedly. No matter the circumstance, always assume that venom has been
injected and seek immediate help if bitten.
Rattlesnakes are born live and are born with fully functional fangs that deliver venom. Newborn rattlesnakes do not have
functional rattles - only after several skin sheddings will a rattlesnake have a useful rattle. In wet weather, if the rattle has
absorbed sufficient water, it will not make noise - another reason not to expect a warning from a rattlesnake. Even with a useful
rattle, a rattlesnake might not always give a warning. There has been speculation that rattlesnakes that use their rattles around
humans are often killed. Natural selection might favor
rattlesnakes that don't give advance warning.
Species and Subspecies
(adapted from Rattlesnake Index )
- Crotalus adamanteus, Eastern Diamondback Rattlesnake
- Crotalus aquilus, Queretaran Blotched Rattlesnake
- Crotalus atrox, Western Diamondback Rattlesnake
- Crotalus basiliscus, Mexican West Coast Rattlesnake
- Crotalus catalinensis, Santa Catalina Island Rattlesnake
- Crotalus cerastes - sidewinders
- Crotalus cerastes cerastes, Mojave Desert Sidewinder
- Crotalus cerastes cercobombus, Sonoran Desert Sidewinder
- Crotalus cerastes laterorepens, Colorado Desert Sidewinder
- Crotalus durissus - tropical rattlesnakes
- Crotalus durissus cascavella, Northeastern Brazilian Rattlesnake
- Crotalus durissus collilineatus, Central Brazilian Rattlesnake
- Crotalus durissus culminatus, Northwestern Neotropical Rattlesnake
- Crotalus durissus cumanensis, Venezuelan Rattlesnake
- Crotalus durissus dryinus, Guianian Rattlesnake
- Crotalus durissus durissus, Neotropical Rattlesnake
- Crotalus durissus marajoensis, Marajoan Rattlesnake
- Crotalus durissus ruruima, Mt. Roriama Rattlesnake
- Crotalus durissus terrificus, South American Rattlesnake
- Crotalus durissus totonacus, Totonacan Rattlesnake
- Crotalus durissus trigonicus, Rupunini Rattlesnake
- Crotalus durissus tzabcan, Yucatan Neotropical Rattlesnake
- Crotalus enyo - Baja rattlesnakes
- Crotalus enyo cerralvensis, Cerralvo Island Diamond Rattlesnake
- Crotalus enyo enyo, Baja California Rattlesnake
- Crotalus enyo furvus, Rosario Rattlesnake
- Crotalus exsul - red diamond rattlesnakes (C. ruber is the preferred synonym)
- Crotalus exsul exsul, [Cedros Island Diamond Rattlesnake]]
- Crotalus horridus - timber rattlesnakes
- Crotalus horridus atricaudatus, Canebrake Rattlesnake
- Crotalus horridus horridus, Timber Rattlesnake
- Crotalus intermedius - small-headed rattlesnakes
- Crotalus intermedius gloydi, Oaxacan Small Headed Rattlesnake
- Crotalus intermedius intermedius, Totalcan Small Headed Rattlesnake
- Crotalus intermedius omiltemanus, Omilteman Small Headed Rattlesnake
- Crotalus lannomi, Autlan Rattlesnake
- Crotalus lepidus - rock rattlesnakes
- Crotalus lepidus castenaeus, Neuvo Leon Rock Rattlesnake
- Crotalus lepidus klauberi, Banded Rock Rattlesnake
- Crotalus lepidus lepidus, Mottled Rock Rattlesnake
- Crotalus lepidus maculosus, Durango Rock Rattlesnake
- Crotalus lepidus morulus, Tamaulipan Rock Rattlesnake
- Crotalus mitchellii - speckled rattlesnakes
- Crotalus mitchellii angelensis, Angel de la Guarda Island Speckled Rattlesnake
- Crotalus mitchellii mitchellii, San Lucan Speckled Rattlesnake
- Crotalus mitchellii muertensis, El Muerto Island rattlesnake
- Crotalus mitchellii pyrrhus, Southwestern Speckled Rattlesnake
- Crotalus mitchellii stephensi, Panamint Rattlesnake
- Crotalus molossus - black-tailed rattlesnakes
- Crotalus molossus estebanensis, San Esteban Island Blacktail Rattlesnake
- Crotalus molossus molossus, Northern Blacktail Rattlesnake
- Crotalus molossus nigrescens, Mexican Blacktail Rattlesnake
- Crotalus molossus oaxacus, Oaxacan Blacktail Rattlesnake
- Crotalus polystictus, Mexican Lance Headed Rattlesnake
- Crotalus pricei - twin-spotted rattlesnake
- Crotalus pricei miquihuanus, Eastern Twin Spotted Rattlesnake
- Crotalus pricei pricei, Western Twin Spotted Rattlesnake
- Crotalus pusillus, Tancitaran Dusky Rattlesnake
- Crotalus ruber - red diamond rattlesnakes (C. exsul is a synonym, but C. ruber preferred)
- Crotalus ruber lorenzoensis, San Lorenzo Island Diamond Rattlesnake
- Crotalus ruber lucansensis, San Lucan Island Diamond Rattlesnake
- Crotalus ruber ruber, Red Diamond Rattlesnake
- Crotalus scutulatus - Mojave rattlesnakes
- Crotalus scutulatus salvini, Humantlan Rattlesnake
- Crotalus scutulatus scutulatus, Mojave Rattlesnake
- Crotalus stejnegeri, Long Tailed Rattlesnake
- Crotalus tigris, Tiger Rattlesnake
- Crotalus tortugensis, Tortuga Island Diamond Rattlesnake
- Crotalus transversus, Cross Banded Mountain Rattlesnake
- Crotalus triseratus - dusky rattlesnake
- Crotalus triseratus armstrongi, Mexican Dusky Rattlesnake
- Crotalus triseratus triseratus, Central Plateau Dusky Rattlesnake
- Crotalus unicolor, Aruba Island Rattlesnake
- Crotalus vegrandis, Uracoan Rattlesnake
- Crotalus viridis - western rattlesnakes
- Crotalus viridis abyssus, Grand Canyon Rattlesnake
- Crotalus viridis caliginis, Coronado Island Rattlesnake
- Crotalus viridis cerberus, Arizona Black Rattlesnake
- Crotalus viridis concolor, Midget Faded Rattlesnake
- Crotalus viridis helleri, Southern Pacific Rattlesnake
- Crotalus viridis lutosus, Great Basin Rattlesnake
- Crotalus viridis nuntius, Hopi Rattlesnake
- Crotalus viridis oreganus, Northern Pacific Rattlesnake
- Crotalus viridis viridis, Prairie Rattlesnake
- Crotalus willardi - ridge-nosed rattlesnake
- Crotalus willardi amabilis, Del Nido Ridgenose Rattlesnake
- Crotalus willardi meridionalis, Southern Ridgenose Rattlesnake
- Crotalus willardi obscurus, New Mexican Ridgenose Rattlesnake
- Crotalus willardi silus, Western Chihuahuan Ridgenose Rattlesnake
- Crotalus willardi willardi, Arizona Ridgenose Rattlesnake
- Sistrurus catenatus - massasaugas
- Sistrurus catenatus catenatus, Eastern Massasauga
- Sistrurus catenatus edwardsii, Desert Grassland Massasauga
- Sistrurus catenatus tergiminus, Western Massasauga
- Sistrurus miliarius - pygmy rattlesnakes
- Sistrurus miliarius barbouri, Dusky Pygmy Rattlesnake
- Sistrurus miliarius miliarius, Carolina Pygmy Rattlesnake
- Sistrurus miliarius streckeri, Western Pygmy Rattlesnake
- Sistrurus ravus - Mexican pygmy rattlesnakes
- Sistrurus ravus brunneus, Oaxacan Pygmy Rattlesnake
- Sistrurus ravus exigus, Guerreran Pygmy Rattlesnake
- Sistrurus ravus ravus, Central Plateau Pygmy Rattlesnake
References
- Manny Rubio; Rattlesnake: A Portrait of a Predator; Smithsonian Institute Press; ISBN 1560988088 (hardcover, 1998)
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