Sistrurus miliarius can be found in the southeastern portion of North America in the following states: North Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi, Kentucky, Tennessee, Louisiana, Arkansas, Texas, Oklahoma, and Missouri (Farrell, 1999).
Biogeographic Regions: nearctic (Native )
endemic to a single nation
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) The range extends from eastern North Carolina to the Florida Keys, west to Oklahoma and eastern Texas, and north to southern Missouri and southwestern Kentucky (Conant and Collins 1991, Palmer and Braswell 1995, Werler and Dixon 2000, Campbell and Lamar 2004, Trauth et al. 2004).
Distribution: USA (E Texas, E Oklahoma, Louisiana, Arkansas, S Missouri, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, W Tennessee) miliarius: USA (North Carolina to Georgia and Alabama) barbouri: USA (South Carolina to Florida and SE Mississippi) streckeri: USA (Mississippi to SW Tennessee and E Texas)
A tiny rattle and a skinny tail can characterize Sistrurus miliarius. The tail rarely has more than a few rattles. This combined with the fact that the rattle is so small causes the sound of the rattle to be similar to the buzzing of an insect (Conant and Collins, 1998). The average size of this relatively small snake is 12-24" (30-61cm). Sistrurus miliarius, like all members of the family Viperidae has facial pits between the nostril and the eye that detect heat energy (King, 1999). Another characteristic of S. miliarius is the nine plates that are present on the crown of its head. The background color of the Pigmy Rattlesnake can vary greatly depending on the location and subspecies. The background color can vary from shades of gray, brown, or black, to even pinkish or reddish. In all species, there is a dark line that runs vertically through the eye that looks similar to the eye of a cat. This line also extends down the side of the face. There is a series of dark, circular spots that mark the center of the back. Along the mid-body line, there is a thin reddish-orange stripe. Along each side of the body you can find dark spots similar but smaller in size than the dorsal spots.
Young Sistrurus miliarius are characterized by a sulfur yellow tip on the tail, as well as a smaller size. The rest of the colorings and markings resembles those of the adult (Farrell, 1999).
Length: 78 cm
Habitat and Ecology
Sistrurus miliarius is found in a variety of habitats that include: rocky and partially wooded hillsides, pine woodlands, along riverbanks, and marshes. The one trait that all of these habitats must have in common is that they are all in close proximity to water. Sistrurus miliarius is seldom found in dry habitats. Pigmy rattlesnakes are good swimmers.
Sistrurus miliarius can often be found in underground retreats. These burrows are not dug by the snakes, but by small mammals or by gopher tortoises (Gopherus polyphemus).
Habitat Regions: temperate ; terrestrial
Wetlands: marsh ; swamp
Other Habitat Features: riparian
- Ernst, C., R. Barbour. 1989. Snakes of Eastern North America. Fairfax, Virginia: George Mason University Press.
- Farrell, T., J. Sunman. 1998. "The Pigmy Rattlesnake Homepage" (On-line). Accessed December 10, 1999 at http://www.stetson.edu/departments/biology/pigpage.html.
Comments: Habitats include wet prairies, wet savannas and pastures, palmetto-pine flatwoods, swamps, hardwood-dominated floodplains, sandhills, mixed pine-hardwood forest, hilly second-growth forests, scrub pinewoods, borders of cypress ponds, vicinity of lakes and marshes, and along rice-field canals and roadside ditches, generally in moist or wet lowlands (Werler and Dixon 2000, Ernst and Ernst 2003). This snake is mainly terrestrial; it shelters under surface cover (logs, stumps, thickets, etc.) or in animal burrows. It swims well; rarely climbs into vegetation.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Like most pit vipers Sistrurus miliarius prefers to sit and wait for its prey. When the prey comes in close range it will ambush it. While waiting for prey S. miliarius will remain in a coiled position; some have been observed to sit in this coiled, immobile position for two to three weeks (Florida Museum of Natural History, 1999). Sistrurus miliarius will also actively hunt for its prey and possibly use its yellowish colored tail to lure to catch its prey (Ernst, 1989). Their choice foods include mice, lizards, snakes, and frogs (Conant-Collins, 1998). They will also eat insects, spiders, centipedes, and nesting birds (Ernst, 1989).
Comments: Eats lizards, snakes, insects, centipedes, spiders, frogs, nestling birds, and small mammals.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 - 300
Comments: This species is represented by a large number of occurences. On a range-wide scale, Campbell and Lamar (2004) mapped hundreds of collection sites.
100,000 - 1,000,000 individuals
Comments: Adult population size is unknown but presumably exceeds 100,000. This snake is common to locally abundant in some areas of suitable habitat in the core of the range.
In Florida, the maximum distance moved from the point of initial capture was 9-242 m (Hudnall 1979). Gravid females are mainly sedentary.
Sources of mortality include various raptors, mammalian carnivores, snake-eating snakes, habitat destruction, and automobiles (Ernst 1992).
Life History and Behavior
Comments: In Florida, may be active in any month but seen most often July-November. In central Florida, found above ground at air temperatures of 14-32 C; prey capture occurred in all months but was lowest in winter; peaks in movement occurred in spring and fall (May et al. 1996). During the warmer months in Florida (Palm Beach County), active in late afternoon and/or at night, basked in the morning; from November to February, main activity was basking in the afternoon (Hudnall 1979). Seldom encountered except in late summer in Alabama (Mount 1975). Active mainly in late spring and early summer in Texas (Tennant 1984). In North Carolina, active March-November. In the north, activity seems to peak from June to September. See Ernst (1992).
Status: captivity: 16.1 years.
Lifespan, longevity, and ageing
Male-male interactions include pinning of the other's head and anterior trunk to the ground. Larger males are more likely to mate with females than smaller males. Once a dominant male is established, the courtship between the dominant male and the female begins. One of these male-female interactions includes mate-guarding behavior. The pair will stay in close proximity; possibly one coiled on top of the other for several days at a time. Mating most often occurs between September and January. Copulation can take several hours to complete. Once complete the female stores sperm from her mate or mates until approximately the following April.
Once the development of embryos begins the female will commonly bask in the sun in order to speed up their development. Unlike many Crotalid species, the female will feed very late into her gestation process. Sistrurus miliarius are oviparous (live bearing) and usually give birth during the month of August. The newborns usually remain close to the mother (usually with in a couple of feet) for several days, or until they complete their first shed (Farrell, 1999).
Mating in nature has been observed in September. Litter size is 2-32 (usually 4-10); 2-11, mean about 6, in central Florida (Farrell et al., 1995, J. Herpetol. 29:21-27). Births occur mostly July-September (mainly August in central Florida) (Farrell et al.. loc. cit.). Newborns are common in southern Florida in July and August (Dalrymple et al., Copeia 1991:294-302). Two Texas litters were born in early to mid-August (Ford et al., 1990, Texas J. Sci. 42:355-368). In central Florida, 26% of females were gravid in two consecutive years, 42% were gravid in one of two consecutive years, and 32% were not gravid in either year (Farrell et al., loc. cit.).
Molecular Biology and Genetics
Statistics of barcoding coverage: Sistrurus miliarius
Public Records: 0
Specimens with Barcodes: 5
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
IUCN Red List of Threatened Species: least concern
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Global Short Term Trend: Relatively stable (=10% change)
Comments: Trend is undocumented, but extent of occurrence, area of occupancy, number of subpopulations, and population size probably are relatively stable or declining at a rate of less than 10 percent over 10 years or three generations.
Global Long Term Trend: Increase of 10-25% to decline of 30%
Degree of Threat: Medium
Comments: No major threats are known. Locally, habitat loss and degradation probably have reduced or eliminated some populations. Between September 1997 and March 1998, a severe skin, eye, and mouth disease (fungal dermatitis and stomatitis) was observed in a population of subspecies barbouri at the Lake Woodruff National Wildlife Refuge in Volusia County, Florida (Cheatwood et al. 2003).
Relevance to Humans and Ecosystems
One benefit of having S. miliarius in your area is that they will capture and eat small rodents and other possible pests to humans.
Comments: Venomous; dangerous to children, but probably incapable of inflicting a fatal bite on an adult human (see Ernst 1992).
A small species with adults usually growing to 40–60 cm (16–24 in) in length. Maximum reported length are 78.8 cm (31.0 in) (Klauber, 1972). Snellings and Collins (1997) reported a specimen of S. m. barbouri measuring 80.3 cm (31.6 in), but it had been in captivity for over 12 years. The largest S. m. barbouri reported by Gloyd (1940) was a specimen measuring 63.8 cm (25.1 in) from St. Petersburg, Florida. Shine (1978) suggested that in some populations males may be larger than females, but a later study by Bishop et al. (1996) did not find sexual dimorphism of any kind in a population in Volusia County, Florida.
The midbody rows of dorsal scales usually number 23. The dorsal pattern consists of a series of oval or subcircular spots with reasonably regular edges. The spots on the flanks are mostly round and not much higher than they are wide. Belly pigmentation towards the rear is more limited to indistinct blotches found on pairs of adjacent scales. Juveniles have a color pattern that is similar to the adults, although it may be paler or more vividly marked, and the tip of the tail is yellow.
Bastard rattlesnake, Carolina ground rattlesnake, Brick red rattlesnake, Carolina pigmy rattlesnake, Catesby's small snake, dwarf rattlesnake, eastern pigmy rattlesnake, grey rattlesnake, ground rattler (Garman, 1887), ground rattlesnake, hog-nosed rattlesnake, little rattlesnake, miliar(y) rattlesnake, North American smaller rattlesnake, oak-leaf rattler, pigmy ground rattlesnake, pigmy rattlesnake, small rattlesnake, southeastern ground rattlesnake, southern ground rattlesnake, southern pigmy rattlesnake, spotted rattler, spotted rattlesnake, southern rattlesnake.
Found in the southeastern United States from southern and eastern North Carolina, south through peninsular Florida and west to eastern Texas and Oklahoma. The type locality given is "Carolina." Schmidt (1953) proposed that this be restricted to "Charleston, South Carolina."
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 stable. Year assessed: 2007.
Usually seen in the summer sunning themselves or crossing the road later in the day. The tiny rattle makes a buzzing sound that can only be heard from a few feet. Some individuals are very aggressive and will strike furiously, while others seem lethargic and do not even attempt to rattle. They do not dig their own burrows, but rather use those dug by small rodents or Gopher Tortoises (Gopherus polyphemus).
Since this species is unable to produce much venom, it is unlikely that it is able to deliver a fatal bite to a human adult. Brimley (1942) wrote that although it was too small to be really dangerous, its bite "will give the victim quite an unpleasant time for several days." However, bites involving children have resulted in prolonged hospitalization and there are also reports of necrosis.
These snakes produce venom that is strongly hemorrhagic and tissue toxic, but devoid of any neurotoxins (Ernst, 1992; Van Mierop, 1976). It is somewhat different in that it contains substantial amounts of serotonin and related tryptamine compounds (Welsh, 1967). Antivenin does not appear to be effective in the treatment of these bites, although CroFab does seem to do a better job than ACP, at least in some animal models. (Consroe et al., 1995).
|Subspecies||Taxon author||Common name||Geographic range|
|S. m. barbouri||Gloyd, 1935||Dusky pigmy rattlesnake||The United States from extreme southern South Carolina through southern Georgia, all of Florida, west through southern Alabama and southeastern Mississippi.|
|S. m. miliarius||(Linnaeus, 1766)||Carolina pigmy rattlesnake||The United States from extreme southern South Carolina, northwards into eastern North Carolina as far as Hyde County and west through central Georgia and central Alabama.|
|S. m. streckeri||Gloyd, 1935||Western pigmy rattlesnake||The United States in Mississippi (except for southeast of the Pearl River Valley), west through Louisiana into eastern Texas, and north into southeastern Oklahoma, Arkansas, southern Missouri and southwestern Tennessee.|
- List of crotaline species and subspecies
- Crotalinae by common name
- Crotalinae by taxonomic synonyms
- McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. ISBN 1-893777-00-6.
- Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. ISBN 0-8014-0463-0.
- "Sistrurus miliarius". Integrated Taxonomic Information System. Retrieved 28 February 2007.
- Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
- U.S. Navy. 1991. Poisonous Snakes of the World. US Govt. New York: Dover Publications Inc. 203 pp. ISBN 0-486-26629-X.
- Sistrurus miliarius at the IUCN Red List. Accessed 15 September 2007.
- 2001 Categories & Criteria (version 3.1) at the IUCN Red List. Accessed 15 September 2007.
- Behler JL, King FW. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. LCCCN 79-2217. ISBN 0-394-50824-6.
- 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. ISBN 0-395-19979-4 (hc), ISBN 0-395-19977-8 (pb).
- Animal Diversity-U. of Michigan (Downloaded Feb. 18, 2010.)
- Ernst, C., R. Barbour. 1989. Snakes of Eastern North America. Fairfax, Virginia: George Mason University Press.
- Norris R. 2004. Venom Poisoning in North American Reptiles. In Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
- Klauber LM. 1997. Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition. First published in 1956, 1972. University of California Press, Berkeley. ISBN 0-520-21056-5.
Names and Taxonomy
Comments: See McCranie (1988) for discussion of evidence that Sistrurus is not a valid genus distinguishable from Crotalus. In contrast, genetic data presented by Knight et al. (1993) indicate that rattlesnakes comprise two sister clades, Crotalus and Sistrurus . However, Parkinson (1999) examined mtDNA variation and found that Crotalus is paraphyletic with regard to the monophyletic Sistrurus.