Sistrurus Tergeminus

''Sistrurus tergeminus'', also known as the western massasauga, is a rattlesnake found in the southwestern plains of the United States and northern Mexico. Like all rattlesnakes, it is a pit viper and is venomous.

Taxonomy

It was once considered a subspecies of the eastern massasauga (''Sistrurus catenatus''). It contains two subspecies: the nominate ''S. t. tergeminus,'' or plains massasauga'','' found in the Great Plains, and '' S. t. edwardsii'', or desert massasauga, found in the deserts of the Southwestern United States and northern Mexico. The latter is considered ''"Vulnerable"'' by NatureServe. According to Campbell and Lamar (2004), a population also exists in southeastern Colorado that is morphologically somewhat intermediate between ''S. t. tergeminus'' and ''S. t. edwardsii''.Campbell JA, Lamar WW. (2004). ''The Venomous Reptiles of the Western Hemisphere''. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. .

Description

Adults range in size from . The standard length for 43 male and 63 female adult specimens was . Conant (1975) mentions an average length of , with a maximum of . Conant R. 1975. ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America''. Second Edition. First published in 1958. Houghton Mifflin Company. Boston. 429 pp. 48 plates. . (pbk.).

The color pattern is similar to that of ''S. catenatus'', but paler: the dark brown blotches contrast strongly with the tan-gray or light gray ground color. The venter (belly) is light with a few dark markings.

Common names

Western massasauga, ground rattlesnake, Gulf Coast massasauga, Wright AH, Wright AA. 1957. ''Handbook of Snakes of the United States and Canada''. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. . ''víbora de cascabel'' (Mexico), Edward's massasauga, large ground rattlesnake, Say's false rattlesnake, Sonora ground rattlesnake, Texas massasauga, three-spotted shield rattler, triple-spotted rattlesnake, prairie massasauga.

Distribution

It is found in the United States in the southwestern plains from southeastern Colorado to 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. Klauber LM. 1997. ''Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind''. Second Edition. First published in 1956, 1972. University of California Press, Berkeley. .Campbell JA, Lamar WW. 2004. ''The Venomous Reptiles of the Western Hemisphere''. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. . It is also found in Mexico, in the states of Tamaulipas, southern Nuevo León, north-central Coahuila, and Samalayuca, Chihuahua.Report on Samalayuca Faun
Reporte de Fauna de la Region de Samalayuca UACJ
The type locality given is "between the Mississippi River and the Rocky Mountains".

Behavior

They are primarily found in grassland areas, on the edge of open woodland, or on rocky hillsides, and often make use of the burrows of other animals for shelter. They primarily eat rodents, but may also eat lizards and frogs, having for the purpose a set of enlarged adrenal glands. Their rattles are significantly higher pitched than those of larger species of rattlesnake, sometimes giving them the nickname "buzztail", and as such should not be relied upon for warning. Primarily nocturnal, the species is considered mild-mannered and sluggish especially during the summer, when the weather is too hot for them to be active and they are sometimes found out sunning themselves. Though they are most often found by water or immediately after rain, they prefer arid or heavily-covered ground.

Venom

Drop for drop, massasauga venom is more potent than that of many larger species of rattlesnakes, but due to the lower yield (the amount it is capable of delivering in a single bite), its potential for harm is greatly reduced. The venom is a powerful hemotoxin which can cause swelling, necrosis, and severe pain. Despite its smaller size and less severe bite, envenomation can still be fatal if untreated, and treatment should be sought immediately for any venomous snake bite. The antivenin CroFab, while not type-specific, can be used to treat severe envenomations from massasaugas.

References

Further reading

* Hubbs, Brian and Brendan O'Connor. 2012. ''A Guide to the Rattlesnakes and other Venomous Serpents of the United States''. Tricolor Books. Tempe, Arizona. 129 pp. . (''Sistrurus catenatus tergeminus'', pp. 74–75.)
* Say, T. ''In'' James, E. 1823. ''Account of an Expedition from Pittsburgh to the Rocky Mountains, Performed in the Years 1819, 1820. By Order of the Hon. J.C. Calhoun, Secretary of War, Under the Command of Maj. S.H. Long, of the U.S. Top. Engineers. Compiled from the Notes of Major Long, Mr. T. Say, and other Gentlemen of the Party. Volume II.'' United States Government. Washington, District of Columbia. (A. & R. Spottiswoode, printer. London.) vii + 356 pp. (''Crotalus tergeminus'', p. 342.)

External links

*

''Sistrurus catenatus''
a
Herps of Texas
. Accessed 1 February 2007.

{{Taxonbar, from=Q7531459

catenatus tergeminus
Fauna of the Plains-Midwest (United States)
Reptiles of the United States
Reptiles of Mexico
Taxa named by Thomas Say