Reptiles of North Carolina
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NC Records

Storeria occipitomaculata - Red-bellied Snake


Photo: Steve Hall
Photo: tom ward
Photo: Anna Kim, David George
Photo: Erich Hofmann
Taxonomy
Class: Reptilia Order: Serpentes Family: Colubridae Subfamily: Natricinae
Taxonomic Comments: Storeria, as currently considered, consists of four species of small, semi-fossorial natricid snakes found throughout much of the eastern United States and into Mexico and Central America. The generic name Storeria was first applied to these snakes in 1853.
Species Comments: Storeria occipitomaculata, the Red-bellied Snake, is one of two species of Storeria found in North Carolina. It ranges throughout the eastern United States, from southeastern Canada and New England south to northern Florida, reaching its western limits in the central US and Canada. A relict population formerly assigned to the subspecies S. o. pahasapae can be found in the Black Hills of western South Dakota and eastern Wyoming.

Previously, three subspecies were recognized; however, recent molecular work by Pyron et al. (2016) showed that the morphology-delimited subspecies do not correspond to molecular lineages. They synonymized all subspecies within S. occipitomaculata, thus no subspecies are currently recognized.

The generic epithet Storeria is a patronym honoring the famed 18th-century American physician and naturalist D.H. Storer, who first described Storeria occipitomaculata (as Coluber occipitomaculatus). The specific epithet occipitomaculata is derived from the Latin occiput, "the back part of the head", and macula, "spot", in reference to the spotting around the neck visible in many individuals.

Taxonomic References: Ernst (2002b; 2012), Pyron et al. (2016).
Identification
Description: Red-bellied Snakes are small, slender snakes with semi-rounded, often blunt heads slightly wider than the neck. Dorsal coloration is variable in this species; the dorsum may have a base color ranging from light brown to red-brown or slate-gray to dark gray. A narrow, lighter middorsal stripe is often present, or may be reduced to two thin, darker dorsolateral stripes or absent altogether. Three light nape blotches (pale yellow to orange) just posterior to the parietal scales on the head are usually present, but these may be fused into a ring or reduced to primarily a single spot. Ventrally, these snakes are typically red or orange, though some have reduced pigmentation making the belly appear yellow or even cream; the ventral coloration typically darkens down the length of the body. The lateral edges of the ventral scales are often flecked with gray or black to varying degrees. The head is typically dark and stippled, fading a bit anteriorly; a white spot on the fifth supralabial, just posterior and inferior to the eye, is often visible.

These snakes are highly variable in color and pattern, even within the same populations. Most can be categorized as either a "light" or "dark" phenotype, and Palmer and Braswell (1995) concluded that more than a third of southeastern coastal specimens were erythristic.

Neonates are typically darker than adults, with very bright nape spots.
Morphological Features: Red-bellied Snakes typically have 15 keeled scale rows throughout the body. Ventral counts range from 107-136 (107-124 in NC specimens; Palmer and Braswell, 1995), with 34-63 subcaudals (34-56) and a divided anal plate. Head scale counts are typically as follows: 6 supralabials, 7 infralabials, 2 nasals, no loreal, 2 preoculars, 2 postocular, and 1+2 temporals. Palmer and Braswell (1995) noted variation in scalation across multiple specimens in NC.

These are typically small snakes, with a maximum total length of 40.6 cm (15.9 inches). Palmer and Braswell (1995) reported a 32.4 cm female specimen from NC. Tail lengths range from 17-28% of total length. Females typically reach larger size than males, have smaller average tail lengths relative to body, and average more ventral scales and fewer subcaudal scales. Males are smaller on average but with longer tails relative to body length, meaning fewer ventrals and more subcaudals.

Red-bellied Snakes lack enlarged posterior teeth or a Duvernoy's gland capable of producing venom. They are inoffensive snakes, harmless to humans and pets, and almost never attempt to bite. When captured, they typically writhe about, releasing musk and feces, and may curl their upper lip in a strange defensive "grin".
Technical Reference: Palmer and Braswell (1995); Ernst and Ernst (2003).
Field Guide Descriptions: Beane et al. (2010).
Online Photos:    Google   iNaturalist   GBIF
Observation Methods: Red-bellied Snakes may be sampled using drift fences with pitfall traps and cover objects. They may be incidentally encountered under cover objects, and frequently encountered in gardens and other semi-urban environments.
Distribution in North Carolina
Distribution Comments: In North Carolina, Red-bellied Snakes can be found essentially statewide, with the exception of the Outer Banks. They have been reported as high as 1700 m.
Distribution Reference: Palmer and Braswell (1995)
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: Red-bellied Snakes are primarily forest species but occur in both upland hardwoods, lowland pine flatwoods and savannas, sandridges, swamp margins, and wooded residential neighborhoods (Beane et al., 2010).
Biotic Relationships: Red-bellied Snakes consume primarily soft-bodied invertebrates such as earthworms and slugs (Brown, 1979; Palmer and Braswell, 1995). Isopods, snails, and beetle larvae are also occasionally reported prey items (Ernst and Ernst, 2003).

Red-bellied Snakes are known prey of many animals, including fish, various ophiophagous snakes (racers, various Lampropeltis kingsnakes, and coralsnakes), birds (including chickens, crows, hawks and falcons), and small mammals (Ernst and Ernst, 2003).
Life History and Autecology
Breeding and Courtship: Female Red-bellied Snakes mature at approximately 15 cm SVL, while males can mature at approximately 14 cm SVL. Mating has been reported spring through fall across the species's range.
Reproductive Mode: Red-bellied Snakes are ovoviviparous, giving birth to "litters" of live young primarily in summer and early fall (June to September). Average litter size is 8 young.

Newly-born young are 8 cm in length on average, and weigh as much as 1.9 g.
Terrestrial Life History: Red-bellied Snakes are secretive and semi-fossorial; Palmer and Braswell (1995) note that they are rarely abroad during the day, but they can be encountered on roads in the spring and fall, suggesting they are more active diurnally in these seasons. Summer activity is usually nocturnal or crepuscular. During the day, they are generally found under surface cover such as logs and fallen pine bark. Red-bellied Snakes have been recorded in North Carolina year-round, with most activity in March–July. They will overwinter in either solitary or communal hibernacula such as rock crevices, loose soil, mammal burrows, rotting logs, or loose bark.

Home range estimates are not known from North Carolina. Estimates elsewhere are thought to be small, though some individuals may move some distance in short periods of time.
General Ecology
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S5
Global Rank: G5

Photo Gallery for Storeria occipitomaculata - Red-bellied Snake

56 photos are available. Only the most recent 30 are shown.

Recorded by: Erich Hofmann and Kayla Weinfurther
New Hanover Co.
Comment: 		Recorded by: Erich Hofmann and Kayla Weinfurther
New Hanover Co.
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Recorded by: Erich Hofmann and Kayla Weinfurther
New Hanover Co.
Comment: 		Recorded by: Erich Hofmann and Kayla Weinfurther
New Hanover Co.
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Recorded by: Sharelle Quick
Union Co.
Comment: 		Recorded by: Guy McGrane
Wilkes/Ashe Co.
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Recorded by: Guy McGrane
Wilkes/Ashe Co.
Comment: 		Recorded by: Cameron Everhart
Mecklenburg Co.
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Recorded by: Carol Ann McCormick
Alamance Co.
Comment: 		Recorded by: Carol Ann McCormick
Alamance Co.
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Recorded by: Carol Ann McCormick
Alamance Co.
Comment: 		Recorded by: K. Bischof, D. Hayden
Transylvania Co.
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Recorded by: K. Bischof, D. Hayden
Transylvania Co.
Comment: 		Recorded by: Anna Kim and David George
Durham Co.
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Recorded by: J. Perry
Stokes Co.
Comment: 		Recorded by: Erich Hofmann
Columbus Co.
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Recorded by: Erich Hofmann
Columbus Co.
Comment: 		Recorded by: Erich Hofmann
Columbus Co.
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Recorded by: Jessica Tate
Forsyth Co.
Comment: 		Recorded by: Jessica Tate
Forsyth Co.
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Recorded by: tom ward
Buncombe Co.
Comment: 		Recorded by: Hunter Phillips
Onslow Co.
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Recorded by: S. Meares
Moore Co.
Comment: 		Recorded by: R. Evans
Onslow Co.
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Recorded by: Erich Hofmann
Craven Co.
Comment: 		Recorded by: Erich Hofmann and Kayla Weinfurther
Craven Co.
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Recorded by: Erich Hofmann and Kayla Weinfurther
Craven Co.
Comment: 		Recorded by: Erich Hofmann and Kayla Weinfurther
Craven Co.
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Recorded by: K. Bischof
Burke Co.
Comment: 		Recorded by: K. Bischof
Burke Co.
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