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Farancia erytrogrammaerytrogramma

By Justin Wood

Geographic Range

Rainbow snakes, Farancia erytrogramma, inhabit the southeastern United States. The range of rainbow snakes extends from southern Maryland to south-central Florida, westward to Louisiana, and the Mississippi River. These snakes are also found in the eastern portion of Virginia. Additionally, they inhibit southern Alabama, southeastern Georgia, northeastern South Carolina, and northern North Carolina. (Hammerson, 2007; Linzey and Clifford, 2002)

Habitat

Rainbow snakes are commonly found in swamps, open marshes, rivers (especially slow-moving streams, blackwater creeks), and brackish water. They are more commonly associated with sandy soils. Rainbow snakes can also be found on mountains, in deciduous forests, or burrowed into sand. Rainbow snakes have been found in burrows up to 3.0 meters below the dry sand surface. Young rainbow snakes are commonly found buried under debris, including logs. They may make shelter out of bald cypress (Taxodium distichum) tree roots, stone piles and downed logs. (Carmichael and Williams, 1991; Hammerson, 2007; Linzey and Clifford, 2002; Palmer and Braswell, 2000; Richmond, 1945; Steen, et al., 2013)

Physical Description

Rainbow snakes are non-venomous, thick-bodied snakes with their main colors being red, black, and yellow. Both sexes have 155 to 177 ventral spots, with females having more spots than males. Scales are smooth and their heads are a little wider than their necks. Their heads are black with red dots on both sides of their heads. There are three longitudinal red stripes across theirs backs. The anal scale is usually divided. Female rainbow snakes have a greater number of posterior scale rows than the males. Adult female rainbow snakes are larger than males, although males have longer, thicker tails. Female total length averages 167.6 cm, while males average 107.4 cm.

At hatching, juvenile rainbow snake length ranges from 8 cm to 19.7 cm. Juvenile rainbow snakes tail tips are pointed but, as they age their tail gradually becomes rounder. Juvenile rainbow snakes resemble adult rainbow snakes but lack any yellow coloration.

Rainbow snakes are distinguished from mud snakes (Farancia abacura) by having 2 internasal scales. Mud snakes have just one. (Breisch, 2017; Palmer and Braswell, 2000; Shelton-Nix, 2017)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • sexes shaped differently
  • Range length
    107.4 to 167.6 cm
    42.28 to 65.98 in

Development

Little is known about the rainbow snake lifecycle. Eggs incubate for 90 days. Hatchlings stay in the nest during the winter and leave in the summer. Hatchlings begin their first growing season at total lengths of 20 to 30 cm. A year later, rainbow snakes are 45 to 55 cm long. Like all snakes, rainbow snakes exhibit indeterminate growth. The juvenile rainbow snakes look similar to the adult rainbow snakes, except the tail tips of the juveniles are sharper. (Gibbons, et al., 1977)

Reproduction

Little is known about rainbow snake mating systems. Male rainbow snakes fight each other to prove their strength to sexually-receptive females. Both males and females mate with multiple individuals per breeding season. (Gibbons and Semlitsch, 1991)

Rainbow snakes breed once yearly, in the late spring or summer months. Their breeding season lasts for three months. Female rainbow snakes are oviparous, laying an average of 20 eggs (range 10 to 52 eggs). The gestation period for rainbow snakes is 60 to 80 days beginning in June to August. Females will remain with the eggs for a period of incubation until the eggs hatch. Female rainbow snakes will burrow their eggs from 10.16 to 45.72 cm underground. Female rainbow snakes remain in the nest with the eggs until they hatch, after which females leave. Eggs hatch in the early fall. Once hatched, young receive no parental care. In winter, young hatchlings stay underground near their nest and move to rivers, streams, swamps, and marshes in the spring. Both sexes reach their sexual maturity at 2 to 3 years. (Jensen, 2008; Linzey and Clifford, 2002)

  • Breeding interval
    Rainbow snakes breed once yearly
  • Breeding season
    Rainbow snakes breed in late spring and summer, including June, July, and August
  • Range number of offspring
    10 to 52
  • Average number of offspring
    20
  • Range gestation period
    60 to 80 days
  • Average time to independence
    0 minutes
  • Range age at sexual or reproductive maturity (female)
    2 to 3 years
  • Range age at sexual or reproductive maturity (male)
    2 to 3 years

After mating, the males will leave the females and provide no parental care. The females will lay their eggs somewhere damp in a nest, often stationed close to a wetland. Females will protect and incubate eggs by coiling around them. Once the eggs hatch, females leave and provide no further care. (Jensen, 2008; Linzey and Clifford, 2002)

  • Parental Investment
  • female parental care
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

Not much has been reported about the lifespan of rainbow snakes in captivity or in the wild. Another member of the genus, Farancia abacura, the mud snake, is known to live 19 years in the wild. It is likely that rainbow snaked have a similar lifespan. (Linzey and Clifford, 2002)

Behavior

Rainbow snakes live in water (natatorial) and also burrow on land (fossorial). Rainbow snakes are adept swimmers, as they often swim along streams or along the substrates of swamps. They are a nocturnal species. Once rainbow snakes have caught their prey, they will get out of the water with the prey in their mouths and swallow them head first. Rainbow snakes are found burrowed under logs, piles of debris, and in moving waters. When there is a drought, rainbow snakes emigrate to forests and mountains. Rainbow snakes are not known to hibernate because they have been captured during every month of the year. If captured and handled, they use their tails to stab the captors, but their tails are not sharp and do not pierce the skin. Male rainbow snakes fight each other to gain access to mating opportunities. Both males and females mate with multiple individuals per breeding season. Regarding predation and behaviors in capturing prey, not much is known about rainbow snakes. However, other members of the genus Farancia curl up with their head lowered beneath their coiled bodies and their tails in the air when a predator approaches. To catch prey, mud snakes (Farancia abacura) push their spear-like tails into the ground and push off to move forward. Mud snakes can smell their prey using their tongue and sense movement via ground vibrations. It's likely that rainbow snakes have similar mechanisms. Both rainbow snakes and mud snakes have spines on the end of their tails that they use to control prey that they have caught. (Carmichael and Williams, 1991; Gibbons and Semlitsch, 1991; Hammerson, 2007)

Home Range

On average, rainbow snakes have been observed 44 m from the nearest wetland boundary (SD 44.91 m, range 0 to 117 m). Individuals have been observed up to 2000 m from the nearest body of water. They are not known to actively defend a territory. (Steen, et al., 2013)

Communication and Perception

Not much has been reported about tactile, acoustic, chemical, or electric communication in rainbow snakes. Other members of the genus Farancia curl up with their heads lowered beneath their coiled bodies and their tails in the air when a predator approaches. To catch prey, mud snakes (Farancia abacura) push their spear-like tails into the ground and push off to move forward. Both the rainbow snakes and mud snakes have spines on the end of thier tails that they use to control prey that they have caught. Mud snakes can sense the heat of a prey. Mud snakes use their tongue to smell any nearby prey and hear by sensing any ground vibrations. It's likely that rainbow snakes have a similar mechanism. (Carmichael and Williams, 1991; Gibbons and Semlitsch, 1991; Hammerson, 2007)

Food Habits

Juvenile rainbow snakes eat fish, salamanders, tadpoles, earthworms, mole salamander larvae Ambystoma talpoideum, and small frogs. Adult rainbow snakes only prey on American eels Anguilla rostrata. Rainbow snakes have been given the name eel moccasins because adults only eat American eels. Rainbow snakes eat their prey alive, swallowing them head first. Once rainbow snakes catch an eel, they climb out of the water and move onto shore or into exposed roots of a bald-cypress tree or underwater shrub to finish digesting their prey and to hide from predators. (Gibbons and Semlitsch, 1991; Linzey and Clifford, 2002; Richmond, 1945)

  • Animal Foods
  • amphibians
  • fish
  • terrestrial worms

Predation

Rainbow snakes are preyed upon by many species. Rainbow snakes give warning signals by coiling their bodies and placing their heads down and raising their tails in the air. They are defenseless; they don't bite and their pointed tail does not inflict a wound. Predators of rainbow snakes include raccoons (Procyon lotor), Virginia opossums (Didelphis virginiana), red-tailed hawks (Buteo jamaicensis), and eastern indigo snakes (Drymarchon couperi). (Carmichael and Williams, 1991; Gibbons and Semlitsch, 1991; Hammerson, 2007; Neill, 1964)

Ecosystem Roles

No parasites have been reported for rainbow snakes. (Carmichael and Williams, 1991; Gibbons and Semlitsch, 1991; Hammerson, 2007; Neill, 1964)

Economic Importance for Humans: Positive

Rainbow snakes are purchased through the pet trade illegally. The harvest rates for rainbow snakes are very low. From 1990 to 1994, in Florida, only one rainbow snake was sold in the pet trade. (; Hammerson, 2007; )

Economic Importance for Humans: Negative

There are no negative economic impacts of rainbow snakes on humans. (Hammerson, 2007)

  • Negative Impacts
  • injures humans
    • bites or stings

Conservation Status

Rainbow snakes are listed as a species of Least Concern on the IUCN Red List. They have no special status for US Federal List, State of Michigan or through CITES. Some rainbow snake populations have declined due to wetlands being drained, urbanization, and being collected for the pet trade. They can be affected by a snake fungal disease, Ophidiomyces ophiodiicola. No other major threats are known and no conservation efforts are currently in place for rainbow snakes. (Guthrie, et al., 2015; Hammerson, 2007)

Contributors

Justin Wood (author), Radford University, Alex Atwood (editor), Radford University, Karen Powers (editor), Radford University, Joshua Turner (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

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. Synapomorphy of the Bilateria.

brackish water

areas with salty water, usually in coastal marshes and estuaries.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

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.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

freshwater

mainly lives in water that is not salty.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

infrared/heat

(as keyword in perception channel section) This animal has a special ability to detect heat from other organisms in its environment.

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.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

natatorial

specialized for swimming

native range

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

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

piscivore

an animal that mainly eats fish

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

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

solitary

lives alone

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

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.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

Breisch, A. 2017. The Snake and the Salamander: Reptiles and Amphibians from Maine to Virginia. Baltimore, Maryland: JHU Press.

Camp, C., W. Gibbons, M. Elliott, J. Jensen. 2008. Amphibians and Reptiles of Georgia. Athens, Georgia: University of Georgia Press.

Carmichael, P., W. Williams. 1991. Florida's Fabulous Reptiles and Amphibians.. Polk County, Florida: World Wide Publications.

Cooper, J. 1960. Another rainbow snake, Abastor erythrogrammus, from Maryland. Chesapeake Science, 1/3/4: 203-204.

Enge, K. 2005. Florida Fish and Wildlife Conservation Commission. Pp. 198-211 in W Meshaka, K Babbitt, eds. Amphibians and Reptiles: Status and Conservation in Florida. Malabar, Florida: Krieger Publishing Company.

Garst, D., J. Willson. 2016. Farancia erytrogramma (rainbow snake). Herpetological Review, 47/4: 682-683.

Gibbons, J., R. Semlitsch. 1991. Guide to the Reptiles and Amphibians of the Savannah River Site. Athens, Georgia: University of Georgia Press.

Gibbons, J., J. Coker, T. Murphy. 1977. Selected aspects of the life history of the rainbow snake. Herpetologica, 23/3: 276-281.

Guthrie, A., S. Knowles, A. Ballmann, J. Lorch. 2015. Detection of snake fungal disease due to Ophidiomyces ophiodiicola in Virginia, USA. Journal of Wilderness Diseases, 53/4: 143-149.

Hammerson, G. 2007. "Farancia erytrogramma" (On-line). The IUCN Red List of Threatened Species 2007: e.T63780A12707838. Accessed September 13, 2017 at http://dx.doi.org/10.2305/IUCN.UK.2007.RLTS.T63780A12707838.en.

Holman, J. 1977. Comments on turtles of the genus Chrysemys Gray. Herpetologica, 33/3: 276.

Hutchens, S., C. DePerno. 2009. Farancia erytrogramma (rainbow snake). Herpetological Review, 4: 355.

Jensen, J. 2008. Amphibians and Reptiles of Georgia. Athens, Georgia: University of Georgia Press.

Linzey, D., M. Clifford. 2002. Snakes of Virginia. Charlottesville, Virginia: University of Virginia Press.

Neill, W. 1964. Taxonomy, natural history, and zoogeography of the rainbow snake, Farancia erytrogramma (Palisot de Beauvois). The American Midland Naturalist, 71/2: 257-295.

Palmer, W., A. Braswell. 2000. Reptiles of North Carolina. Chapel Hill, North Carolina: University of North Carolina Press.

Richmond, N. 1945. The habits of the rainbow snake in Virginia. Copeia, 1945/1: 28-30.

Shelton-Nix, E. 2017. Alabama Wildlife, Volume 5. Tuscaloosa, Alabama: University of Alabama Press.

Steen, D., D. Stevenson, J. Beane, J. Willson, M. Aresco, J. Godwin, S. Graham, L. Smith, J. Howze, D. Rudolph, J. Pierce, J. Lee, B. Gregory, J. Jensen, S. Stiles, J. Stiles, N. Nazdrowicz, C. Guyer. 2013. Terrestrial movements of the red-bellied mudsnake (Farancia abacura) and rainbow snake (F. erytrogramma). Herpetological Review, 44/2: 208-213.

Willson, J., C. Winne, M. Dorcas, J. Whitfield Gibbons. 2006. Post-drought responses of semi-aquatic snakes inhabiting an isolated wetland: Insights on different strategies for persistence in a dynamic habitat. Wetlands, 26/4: 1071-1077.

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