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Redbelly Snake

Storeria occipitomaculata

What do they look like?

Red-bellied Snakes are small snakes, between 20 and 40 cm in length. They are brown, reddish-brown, or gray in color, with a narrow neck and small head. Their upperparts may have 3 to 4 dark stripes that run along the length of the body, or these may be missing. This coloration makes them difficult to see in leaf litter and on soil. The chin and throat are white but the belly is usually bright red, though it can range from pinkish to yellowish, or even gray. There are several white spots along the neck that may fuse to form a white collar. Their scales are keeled (with a ridge along the length of the scale) and males and females are similar in size, though males have slightly longer tails. Young Red-bellied Snakes range in length from 7 to 11 cm and tend to have brighter, more contrasting colors than do adults.

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    20.0 to 40.0 cm
    7.87 to 15.75 in

Where do they live?

Red-bellied Snakes are found throughout North America east of the Rocky Mountains, north of the Gulf of Mexico, and south of southern Ontario, Minnesota, and Saskatchewan.

What kind of habitat do they need?

Red-bellied Snakes are found in woodlands and open meadows, prairies, pastures, marshes, and bogs. They prefer moist soils but are also found in drier sites. Red-bellied Snakes spend much of their time underground or under logs, boards, rocks, or debris.

How do they reproduce?

Red-bellied Snakes breed in the spring or sometimes in late summer. Females give birth in late summer or fall to from 1 to 21 live young, though usually 7 or 8 are born. The young snakes develop quickly and can double their length in their first year. They become mature in their second year.

  • How often does reproduction occur?
    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 (female)
    Sex: female
    730 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    2.0 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    730 days
    AnAge

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

How long do they live?

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
    AnAge

How do they behave?

Red-bellied Snakes seem to be fairly cold tolerant, as they are common in the northern parts of their range. They are active during the day and night, but may become mainly nocturnal during hot weather. Red-bellied Snakes are solitary, except when they congregate with other snakes at hibernation sites. They hibernate in anthills, abandoned animal burrows, in rock crevices, or buildings. Mass migrations occur in the spring (April) and fall (October or November) when these snakes travel to and from their hibernation sites. Much of their time is spent hiding under logs or other cover, but they can be found basking in the open, even climbing small bushes to bask.

How do they communicate with each other?

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.

What do they eat?

Red-bellied snakes eat mainly slugs and earthworms, but will also eat snails, pillbugs, insect larvae, and small salamanders. Red-bellied snakes have special adaptations of their teeth and jaws that allow them to extract snails from their shells, similar to brown snakes.

  • Primary Diet
  • carnivore
    • eats non-insect arthropods

What eats them and how do they avoid being eaten?

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.

What roles do they have in the ecosystem?

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.

How do they interact with us?

Red-bellied Snakes help to control populations of slugs and snails, which are common garden pests.

  • Ways that people benefit from these animals:
  • controls pest population

Are they endangered?

Red-bellied Snakes are widespread and seem to be abundant in some areas. Because they migrate to and from hibernation sites they are often killed in roads in spring and fall. Snakes such as Red-bellied Snakes remain vulnerable to habitat changes and contamination through human activity.

Contributors

Matthew Gates (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

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

carnivore

an animal that mainly eats meat

diurnal
  1. active during the day, 2. lasting for one day.
female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

native range

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

nocturnal

active during the night

ovoviviparous

reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

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.

young precocial

young are relatively well-developed when born

References

Amaral, J. 1999. Lip-curling in Redbelly Snakes (Storeria occipitomaculata): Functional morphology and ecological significance. Journal of Zoology, 248(3): 289-293.

Barret, G., M. Villarroul. 1994. Storeria occipitomaculata occipitomaculata (Northern Red-bellied Snake). Predation. Herpetological Review, 25(1): 29-30.

Behler, J., F. King. 1979. National Audubon Society Field Guide to North American Reptiles and Amphibians. New York, NY: Chanticleer Press and Alfred A. Knopf, Inc..

Blanchard, F. 1937. Data on the natural history of the Red-bellied Snake, Storeria occipitomaculata (Storer), in northern Michigan. Copeia, 1937: 151-162.

Brown, E. 1979. Stray food records from New York and Michigan snakes. American Midland Naturlaist, 102(1): 200-203.

Carpenter, C. 1953. A study of hibernacula and hibernating associations of snakes and amphibians in Michigan. Ecology, 34(1): 74-80.

Harding, J. 1997. Amphibians and Reptiles of the Great Lakes Region. Ann Arbor, Michigan: University of Michigan Press.

Jordan, R. 1970. Death-feigning in a captive Red-bellied Snake, Storeria occipitomaculata (Storer). Herpetologica, 26: 466-468.

Knapik, P., J. Hodgson. 1986. Life history notes. Serpentes. Storeria occipitomaculata (Red belly Snake). Herpetological Review, 17(1): 22.

Oliver, J. 1955. The Natural History of North American Amphibians and Reptiles. Princeton, New Jersey: D. Van Nostrand Company.

Rossman, D., P. Myer. 1990. Behavioral and morphological adaptations for snail exraction in the North American Brown Snakes (Genus Storeria). Journal of Herpetology, 24(4): 434-438.

Semlitsch, R., G. Moran. 1984. Ecology of the Redbelly Snake (Storeria occipitomaculata) using mesic habitats in South Carolina. American Midland Naturalist, 111(1): 33-40.

Smith, H., E. Brodie Jr.. 1982. A Guide to Field Identification: Reptiles of North America. Racine, Wisconsin: Western Publishing Company.

Watermolen, D. 1991. Storeria occipitomaculata occipitomaculata (Northern Red-belly Snake). Behavior. Herpetological Review, 22(2): 61.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Gates, M. 2002. "Storeria occipitomaculata" (On-line), Animal Diversity Web. Accessed April 24, 2014 at http://www.biokids.umich.edu/accounts/Storeria_occipitomaculata/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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