The massasauga (Sistrurus catenatus) is a venomous pitviper species found primarily in the United States. Three subspecies are currently recognized, including the nominate subspecies described here.
The adults are not large, ranging from 45 to 75 cm (18 to 30 in) in length. The color pattern consists of a grey or tan groundcolor, with a row of large rounded brown/black blotches or spots down the centre of the back and three smaller rows of alternating spots down each side. Solid black melanistic examples are also known, as well as cases where the back blotches join with those on the sides. Young massasauga are well-patterned but paler than the adults. This is the only Ontario snake with vertical pupils. It has heat-sensing pits on each side of its smallish head, the scales are keeled and the anal scale is single.
Massasauga, black massasauga, black rattler, black snapper, gray rattlesnake (Iowa, fide Guthrie, 1927), little grey rattlesnake (Canada), muck rattler, prairie rattlesnake, pygmy rattler, spotted rattler, swamp rattler, víbora de cascabel (Mexico), dwarf prairie rattlesnake, eastern massasauga, great adder, ground rattlesnake, Kirtland's rattlesnake, little black rattlesnake (Barton, 1805), massasauga rattlesnake, massasauger, prairie massasauga, rattlesnake, small prairie rattlesnake, snapper, swamp massasauga, swamp rattlesnake, and triple-spotted rattlesnake.
Found in North America from Ontario (Canada) and western New York State southwest to southeastern Arizona (USA) and northern Tamaulipas (Mexico). In Mexico, isolated populations exist in southern Nuevo León, north-central Coahuila and in Samalayuca, Chihuahua. It occurs in various habitats ranging from swamps and marshes to grasslands, usually below 1500 m elevation. The type locality given is "... on the prairies of the upper Missouri" (Valley, USA).
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This species is classified as Least Concern (LC) on the IUCN Red List of Threatened Species (v3.1, 2001). Species are listed as such due to their wide distribution, presumed large population, or because it is unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend is unknown. Year assessed: 2007.
In Indiana and Ohio, the massasauga is listed as an endangered species and Illinois may soon follow. It is also listed in Michigan as Special Concern, and as a candidate for federal listing. However, it does not have any designation on the United States federal Endangered Species Act. The two subspecies found in the drier areas of the southwestern United States and northern Mexico are also considered endangered or at risk by some[who?] state governments.
The Massasauga Rattlesnake is listed as threatened under Ontario's Endangered Species Act, 2007, and is protected under the Fish and Wildlife Conservation Act.  It is found only near the eastern shore of Georgian Bay, the Bruce Peninsula, the North Shore of Lake Huron, Wainfleet Bog, and Ojibway Prairie. It is becoming rare in Canada due to persecution and loss of habitat and is designated as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), as well as the Committee on the Status of Species-at-Risk in Ontario (COSSARO).
In Pennsylvania, the species has experienced a rapid decline, largely because of habitat loss. Historically this has been due to human activity, and more recently primarily from natural forest succession. By 1988, the snake had disappeared from half of the counties that constituted its historical range. A 2003-2005 survey showed only four locations in two counties with confirmed populations. It is classified as critically imperiled to imperiled in the commonwealth.
The diet consists of a variety of small vertebrates, including mammals, lizards, and other snakes, as well as invertebrates such as centipedes. Mammals and reptiles make up their bulk of their diet. Adults feed mainly on rodents, while juveniles usually prey on reptiles: more often lizards in western populations and snakes in eastern ones. Frogs also constitute an important part of their diet: Ruthven (1928) mentioned that in Michigan they made up the main portion of their diet. According to Klauber (1956), S. catenatus feeds on frogs more frequently than any other rattlesnake. In general, however, frogs are not an important part of the diet, although this does seem to be more typical in certain northern and eastern populations.
The venom of rattlesnakes contains specialized digestive enzymes that disrupt blood flow and prevent blood clotting. Severe internal bleeding causes the death of the small animals that this snake eats. After envenomation, the rattlesnake is able to withdraw from the dangers of sharp toothed prey animals until they are subdued and even partially digested by the action of the venom.
S. c. catenatus is rather shy and avoids humans when it can. Most massasauga snakebites in Ontario have occurred after people deliberately handled or accidentally stepped on one of these animals. Both of these scenarios are preventable by avoiding hiking through areas of low visibility (in rattlesnake country) when not wearing shoes and long pants, and by leaving the massasaugas alone when they are found. There are only two recorded incidents of people dying from massasauga rattlesnake bites in Ontario and in both cases they did not receive proper treatment. Recent studies indicate that Ontario Hospitals in rattlesnake country often do not have anti-venom, as Massassauga specific anti-venom is not easy to come by. http://metronews.ca/health/3715/anti-venom-crisis-in-ontario/
|Subspecies||Taxon author||Common name||Geographic range|
|S. c. catenatus||(Rafinesque, 1818)||Eastern Massasauga||United States: central and western New York south of Lake Ontario, western Pennsylvania, northern and central Ohio, northern Indiana, lower Michigan, Illinois, southern and southwestern Wisconsin, extreme southeastern Minnesota, eastern Iowa and northeastern Missouri.|
|S. c. edwardsii||(Baird & Girard, 1853)||Desert Massasauga||United States: extreme southeastern Arizona, central and southern New Mexico, western Texas about as far north and east as the Colorado River, in the Rio Grande Valley, in many of the Gulf Coast counties about as far north as Brazoria, and on several barrier islands including North Padre Island, Matagorda Island and San José Island. Mexico: isolated populations have been reported in the northeast of the country.|
|S. c. tergeminus||(Say, 1823)||Western Massasauga||United States: in the southwestern plains from extreme southeastern Nebraska and northwestern Missouri, southwest through east-central Kansas and west-central Oklahoma into northern and central Texas about as far southwest as the Colorado River.|
Images of S. c. catenatus:
- List of crotaline species and subspecies
- Crotalinae by common name
- Crotalinae by taxonomic synonyms
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- Report on Samalayuca Fauna Reporte de Fauna de la Region de Samalayuca UACJ
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- Indiana Legislative Services Agency (2011), "312 IAC 9-5-4: Endangered species of reptiles and amphibians", Indiana Administrative Code, retrieved 28 Apr 2012
- Michigan Department of Natural Resources, http://www.michigan.gov/dnr/0,1607,7-153-10370_12145_12201-32995--,00.html#what%20to%20do, retrieved 28 May 2012 Missing or empty
- Royal Ontario Museum: Massasauga Rattlesnake
- Rouse, J.D. and Wilson, R.J. 2001. Update COSEWIC Status Report on the Eastern Massasauga, Sistrurus catenatus catenatus. Prepared for the Committee of the Status of Endangered Wildlife in Canada (COSEWIC), November 2001. v+18pp.
- Howard K. Reinert and Lauretta M. Bushar, "The Massasauga Rattlesnake in Pennsylvania: Continuing Habitat Loss and Population Isolation", International Symposium and Workshop on the Conservation of the Eastern Massasauga Rattlesnake, Sistrurus catenatus catenatus, 1992 May 8-9 May, Toronto Zoo, Toronto, Ontario.
- Western Pennsylvania Conservancy: Eastern Massasauga Research
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- Rafinesque, C.S. 1818. Further Accounts of Discoveries in Natural History, in the Western States. American Monthly Magazine and Critical Review 4 (5): 39-42. (Crotalinus catenatus, p. 41.)
|Wikimedia Commons has media related to Sistrurus catenatus.|
|Wikispecies has information related to: Sistrurus catenatus|
- Sistrurus at the Reptarium.cz Reptile Database. Accessed 15 September 2007.
- Eastern Massasauga Fact Sheet at New York State Dept. of Environmental Conservation. Accessed 14 December 2008.
- Massasauga at Encyclopædia Britannica. Accessed 22 June 2005.
- Eastern Massasauga at Learn Anumals. Accessed 30 January 2007.
- Sistrurus catenatus at Herps of Texas. Accessed 30 January 2007.
- Eastern Massasauga in Killbear Provincial Park at Borka's page. Accessed 30 January 2007.
- Massasauga Rattlesnake - Sistrurus catenatus at Herpnet.net, Reptiles and Amphibians of Iowa. Accessed 15 June 2007.
- Eastern Massasauga Rattlesnake (Sistrurus catenatus catenatus), Natural Resources Canada