This species occurs widely in the east of the United States, extending into southern Canada. Its range extends from Nova Scotia to southeastern Saskatchewan, and south to southeastern Texas, the Gulf Coast, and central Florida; isolated population in the Black Hills, Wyoming-South Dakota (Ernst 2002, Ernst and Ernst 2003).

Storeria occipitomaculata, the red-bellied snake, ranges from eastern North Dakota to Nova Scotia, south to Florida, and west to eastern Texas. The Great Plains may act as a barrier to the west, considering that they are also absent from large areas of remnant prairie lands in the parts of the midwest and east. However, a subspecies, Storeria occipitomaculata pahasapae, is found in disjunct populations in the Black Hills of western South Dakota and eastern Wyoming. Another subspecies, Storeria occipitomaculata obscura, is found in Florida and west along the Gulf Coast to eastern Texas. Red-bellied snakes are locally common in woodlands throughout their range (Harding 1997, Smith and Brodie 1982).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) The range extends from Nova Scotia to southeastern Saskatchewan, and south to southeastern Texas, the Gulf Coast, and central Florida; isolated population in the Black Hills, Wyoming-South Dakota (Ernst 2002, Ernst and Ernst 2003).

Continent: North-America
Distribution: S Canada (SE Saskatchewan, Manitoba, Nova Scotia, Ontario, Quebec, Prince Edward Island), E USA (Minnesota, Iowa, SC Nebraska, E Kansas, E Oklahoma, WC/E South Dakota, E North Dakota, E Texas, Missouri, Arkansas, Louisiana, Wisconsin, Illinois, Michigan, Indiana, Ohio, Kentucky, Tennessee, Mississippi, Alabama, Georgia, N Florida, South Carolina, North Carolina, Virginia, West Virginia, Pennsylvania, Delaware, Maryland, New Jersey, New York, Connecticut, Massachusetts, Vermont, S New Hampshire, S Maine)  obscura:
Type locality: Florida, Alachua County, Gainesville. Holotype: FMNH 8561  pahasapae: HOLOTYPE: UIMNH 48564;
Type locality: USA: Dunmire’s Lodge, Lead, Lawrence County, South Dakota; H. M.Smith; August 16, 1960.

The red-bellied snake is a very small snake; total body length ranges from 20.3 cm to 40.6 cm (8-16 in) when fully grown. They are usually brown to reddish brown (although sometimes gray and rarely black) with or without 4 faint, dark dorsal stripes. Occasionally there will be only one, light colored, middorsal stripe, or all five stripes may occur together. The belly is usually a striking bright red, but is known to occur in orange, faint yellow, pink, and infrequently in gray or black. The head is usually brown or reddish brown on top with a white throat and chin underneath. There are three light spots around the neck (one on top and one on each side) that can mix together to form a collar. There are 110-133 ventral scales and 35-61 caudal scales. The midbody contains 15 scale rows. They have keeled scales and a divided anal plate. (Behler 1979, Harding 1997, Smith and Brodie 1982).

Red-bellied snakes are just 7-11 cm at birth. Compared with adults, newborn snakes are darker above and lighter below, and the nape spots create a more distinct neck collar (Harding 1997).

Distinguishing the sex of red-bellied snakes is difficult unless the female is pregnant and therefore heavier and larger. However, males generally have longer tails than females. The female tail is approximately 17-22 percent of the total body length and the male's tail makes up 21-25 percent of the total body length (Harding 1997).

Storeria occipitomaculata subspecies are also hard to differentiate. Some have been know to hybridize, and therefore contain characteristics of both parent species (Harding 1997). However, the Florida red-bellied snake, Storeria occipitomaculata obscura, usually has a more distinct neck collar (neck spots more completely fused), while Storeria occipitomaculata pahasapae of the Black Hills region has very small, faint necks spots or they are completely absent (Behler and King, 1979).

Red-bellied snakes can be confused with brown snakes, Kirtland's snakes, ring-necked snakes and garter snakes. However, red-bellied snakes are usually much smaller than these species. Kirtland's snakes also have a red belly, but it contains two rows of black spots. Ring-necked snakes have a more uniform, prominent collar and they have smooth (rather than keeled) scales. The brown snake has a light belly and 17 midbody scale rows. Garter snakes also have a lighter belly and an undivided anal plate (Harding 1997).

Range length: 20.0 to 40.0 cm.

Other Physical Features: ectothermic ; bilateral symmetry

Sexual Dimorphism: sexes shaped differently

Length: 41 cm

Paratype for Storeria occipitomaculata pahasapae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1891
Locality: Hill City, Pennington, South Dakota, United States, North America

Habitat and Ecology

Systems

• Terrestrial

Red-bellied snakes are most abundant in deciduous and mixed woodlands. They generally like a damp, moist, and cool environment. Unsurprisingly, they are often found in mesic environments, such as river bays, creek bottomlands, and sphagnum bogs where slugs, snails and worms are readily available. They often hide under bark, logs, rocks, and leaf litter. However, they are still common in drier sites such as pastures and grasslands adjacent to woodlands (Harding 1997, Semlitsch and Moran 1984). Quite often they are seen around human habitations. They tend to hide in vacant lots around trash, under boards, and other debris. Occasionally red-bellied snakes are seen basking in the open sun and sometimes climb into low shrubs and other vegetation (Harding 1997).

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: forest

Wetlands: marsh ; bog

Comments: Habitats are varied and include mountainous or hilly woodland/forest, upland meadows and valleys, and swamp and bog edges (Ernst and Ernst 2003). This snake shelters under and in ground cover, in building foundations, and in abandoned ant mounds. Generally it occurs in mesic situations with abundant ground cover.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: Yes. At least some 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.

Migrates between winter hibernaculum and summer range in at least some areas (Vogt 1981).

Red-bellied snakes are specialized feeders of gastropods. Stomach content analysis has revealed that at certain times they may feed exclusively on slugs (Brown 1979, Semlitsch and Moran 1984). Earth worms and snails are also very common food items, while insect larvae and pill bugs, and possibly young salamanders serve as food items (Harding 1997).

They have a number of adaptations to aid their specialized gastropod diet. The teeth of S. occipitomaculata are especially slender and in-curved so they can more easily grasp and hold on to the slimy, soft bodies of slugs and snails (Amaral 1999). Their skulls are also proportionately smaller than other snakes, which may aid in extracting snails from their shells (Rossman and Myer 1999). It is possible that they release very weak venom from their Duvernoy glands during prey seizure. This venom may serve to both weaken the prey (reducing prey-handling time) and reduce the effects of the snail's mucous secretions (Amaral 1999).

Primary Diet: carnivore (Eats non-insect arthropods)

Comments: Eats mainly various small invertebrates, including slugs, snails, earthworms, isopods, and beetle larvae.

Red-bellied Snakes help to control populations of slugs, snails, and earthworms. They are also a valuable food source for the animals who prey on them.

Red-bellied snakes are eaten by a number of predators, including American crows, milk snakes, hawks, shrews, thirteen-lined ground squirrels, raccoons, and domestic cats. They do not bite in response to a threat but will flatten their bodies and curl their upper 'lips' as a form of warning. These snakes are very small, though, and their teeth wouldn't harm any but the tiniest of predators. They can emit a foul-smelling substance and smear it on their attacker if harassed. Some will stiffen and roll onto their backs when harassed, playing dead. This exposes their bright red belly and may be enough to startle a predator momentarily and allow escape.

Known Predators:

• American crows (Corvus brachyrhynchos)
• milk snakes (Lampropeltis triangulum)
• raccoons (Procyon lotor)
• shrews (Soricidae)
• hawks (Accipitridae)
• thirteen-lined ground squirrels (Spermophilus tridecemlineatus)
• domestic cats (Felis silvestris)

Storeria occipitomaculata is prey of:
Accipitridae
Soricidae
Lampropeltis triangulum
Corvus brachyrhynchos
Spermophilus tridecemlineatus
Procyon lotor
Felis silvestris

This list may not be complete but is based on published studies.

Storeria occipitomaculata preys on:
non-insect arthropods

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: This species is represented by a large number of occurrences (subpopulations) (Ernst 2002).

100,000 to >1,000,000 individuals

Comments: Adult population size is unknown but presumably exceeds 100,000. This snake, though secretive and sometimes hard to detect, is locally common in many parts of its large range.

Red-bellied Snakes communicate with each other primarily through touch and smell, especially during breeding. Outside of the breeding season they do not interact much with other snakes. They use their forked tongues to collect chemicals from the air and insert these forks into a special organ in the roof of their mouth, which interprets these chemical signals. Snakes are also sensitive to vibrations and have reasonably good vision.

Comments: Inactive from November through March or April in north (Vogt 1981, DeGraaf and Rudis 1983). Active during all months in South Carolina.

Red-bellied Snakes have been known to live 4 years in captivity. They may live longer in the wild but this is poorly known.

Range lifespan

Status: captivity: 4.0 (high) years.

Average lifespan

Status: captivity: 4.6 years.

Maximum longevity: 4.6 years (captivity) Observations: Maximum longevity is most likely underestimated since few animals have been kept in captivity.

Mating System: polygynous

Red-bellied snakes typically mate in spring and early summer, but may also mate in late summer and fall. They give birth to live young usually between late July and early September in northern regions and sometimes later in the south. Litter size ranges from 1-21, but normally only 7 or 8 are born (Harding 1997), with approximately equal numbers of each sex (Blanchard 1937). The largest females invest more energy in reproduction, producing a higher number of young (but not necessarily larger young) than smaller females (Brodie and Ducey 1989). Studies have shown that nearly all females captured in the spring are gravid, suggesting that they are very successful breeders (Semlitsch and Moran 1984).

Newborn snakes grow quickly, often doubling their length within the first year (Harding 1997). By their second year they are sexually mature and begin mating. Minimum length for sexual maturity is 22 cm (Blanchard 1937). It is not known how long they live in the wild, but captives may live at least four years (Harding 1997).

Breeding interval: Red-bellied Snakes breed once or twice each year.

Breeding season: Red-bellied Snakes have their young in late summer and fall.

Range number of offspring: 1.0 to 21.0.

Average number of offspring: 7.0.

Average age at sexual or reproductive maturity (female): 2.0 years.

Average age at sexual or reproductive maturity (male): 2.0 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); ovoviviparous

Average age at sexual or reproductive maturity (male)

Sex: male: 730 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 730 days.

Female Red-bellied Snakes nurture their young in their bodies until they are born. At that point there is no further parental care.

Parental Investment: precocial ; female parental care

Litter size 1-21 (average 9 in South Carolina, 7 in Michigan); larger females have larger litters; young born late July-early September in Michigan, July-August in South Carolina; females breed annually; sexually mature in 2 years (Behler and King 1979, Semlitsch and Moran 1984).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 2
Species With Barcodes: 1

Red-bellied snakes often turn up around lumber, sheet metal, and other debris around homes, abandoned buildings, and trash dumps. Their proximity to humans can often result in death by some fearful person.

Red-bellied snakes are, currently, locally common in areas of suitable habitat. However, habitat fragmentation is probably reducing their numbers to some degree. They are often killed in large numbers while crossing roadways during migrations to and from their hibernacula. People should be educated on the harmlessness and value of this species (Harding 1997).

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Population

Population Trend

Global Short Term Trend: Relatively stable (=10% change)

Comments: 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%

Major Threats

Comments: No major threats are known. This snake is tolerant of minor habitat alterations.

Conservation Actions

Global Protection: Very many (>40) occurrences appropriately protected and managed

Comments: Many occurrences are in protected areas.

Although seemingly insignificant, red-bellied snakes may be important to us in any number of unforseen ways. They are likely an important link in the food web as both predator and prey, and are therefore important in sustaining the integrity of our natural ecosystems. The condition of our ecosystems will likely, in time, be reflected in our economy.

In addition to food web relationships, their consumption of slugs, snails, and occasionally insects and larvae, may aid in controlling these pests in our farmlands and gardens (Harding 1997).

Positive Impacts: controls pest population

Comments: There are two distinct dorsal color morphs, light charcoal gray and medium brown; allozyme evidence confirms that they are members of a common gene pool (Grudzien and Owens 1991).

Subspecies pahasapae is thought to intergrade with subspecies S. o. occipitomaculata over a wide area in Minnesota, southern Manitoba, and adjacent areas. However, this might represent clinal variation, and validity of the subspecies designations is open to question. Further study of variation in the northwestern part of the range of S. occipitomaculata is needed (Ernst 2002).