Sistrurus miliariusPigmy Rattlesnake

Geographic Range

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).

Habitat

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). (Ernst and Barbour, 1989; Farrell and Sunman, 1998)

Physical Description

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).

Reproduction

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).

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    16.1 years
    AnAge

Behavior

Sistrurus miliarius has a relatively unique way of defending it self when approached by humans. Its defensive behavior is to remain motionless, and even though these are rattlesnakes they rarely warn someone approaching by sounding their rattle. At most the may sway their head slightly from side to side. They have a reputation for being very aggressive which is probably not well deserved. The bite from S. miliarius can be very painful and can cause the loss of a digit. It rarely causes death and if it does it is usually due to complications (King, 1999). One study found if a coiled snake is encountered it will usually remain motionless. However, 16.4% flee, 2.5% strike, and 3.3% will strike when grabbed. The study also found that snakes with a higher body temperature are more likely to strike (Terry Farrell, 1999).

Food Habits

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).

Economic Importance for Humans: Positive

One benefit of having S. miliarius in your area is that they will capture and eat small rodents and other possible pests to humans.

Conservation Status

Other Comments

There are actually three different subspecies of the Pigmy Rattlesnake. They are the Carolina Pigmy (S. miliarius miliarius), the Dusky Pigmy (S. miliarius barbouri), and the Western Pigmy (S. miliarius streckeri) (Conant-Collins, 1998). The Carolina pigmy is gray to reddish-brown, and is found from Hyde County, North Carolina southwest to central Alabama. The Dusky pigmy is dark gray and ranges from southwestern South Carolina down through Florida, and into southern Georiga, Alabama, and southeastern Mississippi. The Western pigmy is gray-brown to brown in color and can be found in western Kentucky and Tennessee, southern Missouri, and eastern Oklahoma south into Louisiana and Texas (Bartlett, 1999).

Contributors

Darren Kalis (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

marsh

marshes are wetland areas often dominated by grasses and reeds.

native range

the area in which the animal is naturally found, the region in which it is endemic.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

References

Conant, R., J. Collins. 1998. A Field Guide To Reptiles and Amphibians. Boston: Houghton Mifflin Company.

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.

King, F. 1996. "Florida Museum of Natural History’s Guide to Florida’s Venomous Snakes" (On-line). Accessed December 10, 1999 at http://www.flmnh.ufl.edu/natsci/herpetology/fl-guide/venomsnk.htm#TOP.