Sistrurus miliarius
Sistrurus miliarius, commonly called the pygmy rattlesnake, is a species of venomous snake in the subfamily Crotalinae (pit vipers) of the family Viperidae. The species is endemic to the Southeastern United States. Three subspecies are currently recognized. Description. "S. miliarius" is a small species, with adults usually growing to in total length (including tail). The maximum reported total length is (Klauber, 1972). Snellings and Collins (1997) reported a specimen of "S. m. barbouri" measuring , but it had been in captivity for over 12 years. The largest "S. m. barbouri" reported by Gloyd (1940) was a specimen measuring 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. At midbody, the rows of dorsal scales usually number 23. The dorsal pattern consists of a series of oval or subcircular spots with somewhat 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 ' color patterns are similar to the adults, although they may be paler or more vividly marked, and the tips of their tails are yellow. Common names. Common names for "S. miliarius" include pygmy rattlesnake, ground rattlesnake, hog-nosed rattlesnake, little rattlesnake, miliar(y) rattlesnake, North American smaller rattlesnake, oak-leaf rattler, pygmy ground rattlesnake, small rattlesnake, southeastern ground rattlesnake, southern ground rattlesnake, southern pygmy rattlesnake, spotted rattler, spotted rattlesnake, southern rattlesnake. Older common names might include bastard rattlesnake, nipple snake, Carolina ground rattlesnake, brick red rattlesnake, Carolina pygmy rattlesnake, Catesby's small snake, dwarf rattlesnake, eastern pygmy rattlesnake, grey rattlesnake, and  ground rattler (Garman, 1887). Geographic range. "S. miliarius" is found in the Southeastern United States from southern and eastern North Carolina, south through peninsular Florida and west to East Texas and Oklahoma. The type locality given is "Carolina". Schmidt (1953) proposed that this be restricted to "Charleston, South Carolina". Habitat. "Sistrurus miliarius" reportedly inhabits flatwoods, sandhills, mixed forests, and floodplains, and is also found near lakes and marshes. Conservation status. This species is classified as least concern 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 the population is unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend is stable; it was assessed in 2007. This species is not protected by South Carolina or Georgia state law, but pygmy rattlesnakes are protected in North Carolina and Tennessee. Behavior. "S. miliarius" is usually seen in the summer sunning itself or crossing the road late in the day. The tiny rattle makes a buzzing sound that can only be heard from a few feet away. Some individuals are very aggressive and strike furiously, while others seem lethargic  and do not even attempt to rattle. It does not dig its own burrows, but rather uses those dug by small rodents or gopher tortoises ("Gopherus polyphemus"). Feeding. The diet of "S. miliarius" includes small mammals and birds, lizards, insects, and frogs, as well as other snakes. Pygmy rattlesnakes also include giant desert centipedes in their diet, which they hunt by active pursuit, grabbing and flipping the centipedes around while simultaneously injecting venom to prevent injury by the victim. They also ambush lizards such as skinks by using their tails as lures, as is common in many other species of  vipers. Caudal luring becomes less effective for adults, as the prey size and type changes. Their feeding strategy becomes sit-and-wait, with individuals remaining in a coiled position for days at a time. Venom. Since "S. miliarius" is unable to produce much venom, it is unlikely to be 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, with reports of necrosis. This snake  produces cytotoxic venom that is strongly hemorrhagic and tissue toxic, but devoid of any neurotoxins. The venom was the basis for the development of the drug eptifibatide, which is used to prevent clotting during a heart attack. The venom is somewhat different in that it contains substantial amounts of serotonin and related tryptamine compounds. Antivenin does not appear to be effective in the treatment of bites of "S. miliarius", although CroFab does seem to do a better job than ACP, at least in some animal models.