Reptiles of North Carolina
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NC Records

Sistrurus miliarius - Pygmy Rattlesnake


Photo: N. Crider
Photo: T. Taylor, J. Davis, J. Privette
Photo: K. Bischof
Taxonomy
Class: Reptilia Order: Serpentes Family: VIPERIDAE Subfamily: Crotalinae Other Common Name(s): Pigmy Rattlesnake
Taxonomic Comments: Sistrurus comprises three species of small venomous rattlesnake found disjunctly across eastern and central North America, from southern Canada to extreme northern Mexico.

Species Comments: Sistrurus miliarius, the Pygmy Rattlesnake, is the only member of its genus in North Carolina. It found along the southeastern United States, from southern North Carolina to Florida, west to east Texas and up to Missouri. In North Carolina, Pygmy Rattlesnakes are restricted to the southern Coastal Plain, with a few records in the southern Piedmont.

Three subspecies of Pygmy Rattlesnake are recognized, with all North Carolina specimens assignable to the nominate S. m. miliarius, the Carolina Pygmy Rattlesnake. These subspecies are weakly supported by molecular data (Kubatko et al., 2011).

The generic epithet Sistrurus is derived from the Latin sistrum, "rattle". The specific epithet miliarius is derived from the Latin milium, "millet-like" or "of millet", presumably in reference to its pattern.

Taxonomic References: Palmer (1978); Campbell and Lamar (2004)
Identification
Description: Pygmy Rattlesnakes are small, relatively slender rattlesnakes with tiny rattles. Most are gray, brown, or light red, with a narrow reddish or light orange middorsal stripe and dark brown to black middorsal blotches. Laterally, a series of alternating dark spots or smudges are visible. Two dark, thick bands stretch from the posterior supraoculars to the nape, and there is a distinct postocular stripe extending to the rear of the jaw, often bordered by a pale line. The venter is white or pink, with visible dark spots.

Populations in the Albemarle-Pamlico Sound region are among the most striking snakes in the country, characterized by a brilliant red to pinkish red dorsal color; they are often colloquially referred to as "red pygmy rattlesnakes".

Juveniles and neonates often have white or yellowish tails tipped with a "button" rather than a rattle.
Morphological Features: Pygmy Rattlesnakes typically have 21-23 keeled dorsal scale rows at midbody. Ventral counts range from 122-148 (123-141 in NC specimens; Palmer and Braswell, 1995), with 25-39 (26-36) subcaudals and an undivided anal plate. Head scale counts are typically: 9-12 supralabials, 9-13 infralabials, 1 large loreal, 2 preoculars, 3-6 postoculars, 2 nasals, and 4-5 rows of temporals. Palmer and Braswell (1995) noted some variation in scalation across multiple specimens.

Pygmy Rattlesnakes have a maximum recorded total length of 83.2 cm (32.7 inches), though most are smaller. Palmer and Braswell (1995) reported a 74.3 cm captive female specimen from NC; the largest wild specimen they reported was a 69.0 cm male. Tail lengths account for only around 9-13% of total length. Males tend to have longer tails than females.

Pygmy Rattlesnakes are solenoglyphous, meaning they have elongated, hollow fangs that direct venom like a hypodermic needle. These fangs are extended out during a strike, and folded into the mouth when it is closed. Pygmy Rattlesnakes are venomous, and should not be handled. Their venom is hemotoxic, meaning it works by attacking the blood and causing hemorrhaging; local swelling, pain, and hemorrhaging at the bite site are common symptoms, as are secondary infections.

Pygmy Rattlesnakes, when threatened, will flee quickly if able. They will sometimes coil and rattle their tail, making a soft, insect-like buzz that is difficult to hear. They will strike quickly and often without warning. Pygmy Rattlesnake bites are somewhat common but human fatalities have not been reported.
Technical Reference: Palmer and Braswell (1995); Ernst and Ernst (2003, 2011); Campbell and Lamar (2004)
Field Guide Descriptions: Beane et al. (2010).
Online Photos:    Google   iNaturalist   GBIF
Observation Methods: Pygmy Rattlesnakes can be found under or near cover in preferred habitat, sampled using drift fences and cover arrays, and occasionally found crossing roads between habitat.
Distribution in North Carolina
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: Pygmy Rattlesnakes are associated with mixed pine-oak woodlands in the Coastal Plain. In the southern half of the Coastal Plain, xeric pine-oak sandhills comprise the main habitats but in the northern half, more mesic forests composed of Loblolly Pines and hardwoods are used (Palmer and Braswell, 1995). Areas close to depression ponds and other wetlands may be preferred (Beane et al., 2010).
Life History and Autecology
Breeding and Courtship: Pygmy Rattlesnakes reach sexual maturity at minimum body lengths of 38 cm. These snakes typically mate in spring and summer, though mating records from elsewhere in their range occurred in August to November.
Reproductive Mode: Pygmy Rattlesnakes are ovoviviparous, giving birth to young enclosed in an amniotic sac; young are typically born July to September. Litters average 7 neonates.

Neonates average 16 cm in total length and weigh up to 6 g, often with brighter colored tail tips. Contrary to popular belief, neonate and juvenile rattlesnakes are not more venomous (or more likely to envenomate) than adults; juvenile venom glands are substantially smaller, and thus venom capacity is much smaller.
Terrestrial Life History: Pygmy Rattlesnakes are active both diurnally and nocturnally, and like many other species they become more crepuscular/nocturnal activity as temperatures peak in the summer. Daily activity includes basking and sheltering under cover objects or within vegetation when not active, and individuals are often seen on roads. These snakes are primarily terrestrial but can climb short distances into trees and bushes. There are North Carolina records from every month, with most coming from summer and early fall (July–October).

Home range estimates are not known from North Carolina. A study in Missouri found that Pygmy Rattlesnakes undertake short movements in small home ranges that average only 0.2 hectares (2,000 m2) for gravid females, 0.8 ha for nongravid females, and 1.4 ha for males (Maag et al., 2022). Gravid females are typically fairly sessile, often not moving more than a couple meters over multiple days.
General Ecology
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S2
Global Rank: G5
Status in North Carolina: SC

Photo Gallery for Sistrurus miliarius - Pygmy Rattlesnake

25 photos are shown.

Recorded by: C. Teague
Beaufort Co.
Comment: 		Recorded by: B. Fleming
Carteret Co.
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Recorded by: C. Teague
Beaufort Co.
Comment: 		Recorded by: C. Teague, B. Bockhahn, C. Blake
Beaufort Co.
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Recorded by: M. Briley
Beaufort Co.
Comment: 		Recorded by: W. Morris
Beaufort Co.
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Recorded by: M. Briley
Beaufort Co.
Comment: 		Recorded by: Ed Corey
Onslow Co.
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Recorded by: K. Bischof
Beaufort Co.
Comment: 		Recorded by: K. Bischof
Beaufort Co.
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Recorded by: Candie Bates (Park Visitor)
New Hanover Co.
Comment: 		Recorded by: N. Crider
Beaufort Co.
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Recorded by: N. Crider
Beaufort Co.
Comment: 		Recorded by: Jason Brown
New Hanover Co.
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Recorded by: N. Crider
Beaufort Co.
Comment: 		Recorded by: Erich Hofmann
New Hanover Co.
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Recorded by: Erich Hofmann
New Hanover Co.
Comment: 		Recorded by: K. Bischof, S. Windley
Beaufort Co.
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Recorded by: K. Bischof
Beaufort Co.
Comment: 		Recorded by: K. Bischof, C. Cabral
Beaufort Co.
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Recorded by: K. Bischof, M. Smith
Beaufort Co.
Comment: 		Recorded by: K. Bischof, K. Thompson
Beaufort Co.
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Recorded by: Carla Edwards
New Hanover Co.
Comment: 		Recorded by: T. Taylor, J. Davis, J. Privette
New Hanover Co.
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Recorded by: P. Wahab, C. Dykstra
Beaufort Co.
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