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Pantherophis guttatusRed corn snake

By Sarah Hogrefe

Geographic Range

Corn snakes are found throughout the eastern and southern central United States, into northern Mexico. Two subspecies, Pantherophis guttatus guttatus (corn snake) and P. guttatus emoryi (Great Plains rat snake) are currently recognized. Corn snakes are found from southern New Jersey to Florida and westward through Mississippi to Louisiana. The range of Great Plains rat snakes extends from southwestern Illinois through Texas and into northern Mexico, and as far west as eastern New Mexico. (Bartlett and Bartlett, 2005; Burbrink, 2002; Conant and Collins, 1998)

Habitat

Corn snakes can be found in a wide variety of terrestrial habitats, preferring deciduous forests and rocky regions where crevices and logs provide nests. They can also be found in fields, grassy areas, and in suburban areas near homes and barns. This species has been found in mountainous regions up to about 1800 m in elevation but typically prefer lower elevations. (Bartlett and Bartlett, 2005)

  • Range elevation
    1800 (high) m
    5905.51 (high) ft

Physical Description

Corn snakes are mild-tempered, non-venomous snakes. Large spots run along dorsal side of the body, while the flat underside commonly has a black and white checkered pattern. The body tends to be brown and red-orange, but colors vary with region and can include gray and yellow. In captivity, breeders have created a wide variety of color patterns, or morphs. Pet corn snakes range in color from white to yellow to black, though most still retain the primary red/brown colors. Captive patterns include spots, stripes, and solid coloring over the snake's body. Males are larger than females, with an average length of 70 to 120 cm for the combined sexes. Snakes in warmer climates tend to be shorter, with an average adult length of approximately 48 cm. Hatchlings are paler and duller when they first hatch, and measure 20 to 35 cm. (Bartlett and Bartlett, 2005; Mattison, 2007)

Corn snakes can sometimes be confused with venomous southern copperheads (Agkistrodon contortrix), but the two can be differentiated by the narrower head, lighter coloration, and square-shaped spots that are found in red corn snakes. (Bartlett and Bartlett, 2005; Mattison, 2007)

  • Sexual Dimorphism
  • male larger
  • Average mass
    900 g
    31.72 oz
    AnAge
  • Range length
    48 to 120 cm
    18.90 to 47.24 in

Development

Juvenile corn snakes are fully developed when hatched. This species has ZZ/ZW sex determination, with the male snake contributing only Z chromosomes, while the female contributes the Z or W chromosome that determines the gender of the hatchlings (ZZ=male, ZW=female). (Ernst and Barbour, 1989)

As they grow, juvenile corn snakes shed their skin several times, and will continue to shed after reaching adulthood. After shedding, the coloration of the scales turns more vivid and the patterns become clearer. Growth is directly related to how much food is available to the snake; juveniles grow faster on a regular diet of warm-blooded animals. In general, a juvenile reaches its full length shortly after reaching sexual maturity, at around two years of age. (Ernst and Barbour, 1989; Mattison, 2007)

Reproduction

Not much is known about the mating systems of corn snakes. During mating season, the snakes locate each other using pheromones. Males fight each other for dominance, with the dominant male earning mating rites to the female. (Ernst and Barbour, 1989)

Corn snakes reach sexual maturity at 16 to 18 months of age. Depending on the climate, the breeding season lasts from March to May, or year-round in the south. Gestation lasts one to two months, with females laying 10 to 15 (up to 30) eggs from May to early July in stumps, logs, or burrows that are warm and humid. The eggs are white and cylindrical, measuring 3.8 to 6.4 cm in length and 1.3 to 2.5 cm in diameter. Finding a corn snake nest is very rare, because females seek out secluded nesting sites. After approximately two months of incubation at an ideal temperature of 27.8 degrees Celsius, the eggs hatch between July and September. Not all healthy eggs hatch, as some hatchlings cannot penetrate the tough eggshell. (Ernst and Barbour, 1989; Mattison, 2007; Seigel and Ford, 1991; Stewart, et al., 2004)

Females in the wild lay one clutch of eggs per year. In captivity, female corn snakes may lay a second clutch of eggs. If a female snake breeds a second time, she can produce fertile eggs within days of laying her first clutch. She will lay her second clutch following the same timeline as the first. (Ernst and Barbour, 1989; Seigel and Ford, 1991)

  • Breeding interval
    Wild corn snakes breed once annually.
  • Breeding season
    Snakes mate in spring; eggs hatch during the summer.
  • Range number of offspring
    10 to 30
  • Average number of offspring
    10-15
  • Average number of offspring
    12
    AnAge
  • Range gestation period
    35 to 68 days
  • Range age at sexual or reproductive maturity (female)
    16 to 18 months
  • Range age at sexual or reproductive maturity (male)
    16 to 18 months

Corn snakes provide no care to their young. Male snakes leave the female after mating, and females leave their eggs after laying them in a secluded nest. (Mattison, 2007)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

The longest recorded lifespan of this species in captivity was just over 32 years. Although no information on lifespan in the wild is currently available, it can be reasonably assumed that predation and disease cause wild individuals to have shorter average lifespans. (de Magalhaes and Costa, 2009)

  • Range lifespan
    Status: captivity
    32.3 (high) years
  • Average lifespan
    Status: captivity
    32.3 years
    AnAge

Behavior

Corn snakes climb trees or bushes to hunt for prey. In areas in which the primary diet is rodents, they also spend time underground in the burrows of their prey. When they are not hunting, they spend much of their time basking on rocks. (Bartlett and Bartlett, 2005; Ernst and Barbour, 1989; Mattison, 2007; Sievert, et al., 2005)

When shedding their skins, corn snakes become aggressive and reclusive. They first rub their nose against rocks and sticks to loosen the skin from the head. Once this is accomplished, they will slither forward and the rest of the skin slides off in one long piece. Shedding also seems to decrease a snake's appetite, but once the old skin is shed the snake hunts and eats normally. (Bartlett and Bartlett, 2005; Mattison, 2007)

Corn snake activity varies among regions, generally becoming more active farther south in the species’ range. Red corn snakes are generally diurnal, but during warmer periods or in warmer climates scientists have observed them to be crepuscular. They hibernate in crevices like logs or caves during the winter. In most of their range, corn snakes begin hibernation around October, emerging in the spring around April. Corn snakes in southern regions have been observed to hibernate for very brief periods, if at all. (Bartlett and Bartlett, 2005; Ernst and Barbour, 1989; Mattison, 2007; Sievert, et al., 2005)

When male corn snakes encounter each other, they may perform displays of dominance, especially during mating season. A male snake shows domination by a series of spastic movements and restricting the movement of the weaker male. (Ernst and Barbour, 1989)

  • Range territory size
    39800 to 269500 m^2

Home Range

Great Plains rat snakes have home ranges that increase and decrease in size with the seasons, reaching peaks in the late spring and early autumn. Territory size ranged from 3.980 ha in the winter to 2.695 ha during peak seasons and did not overlap with the territories of other rat snakes. Because of the limited number of studies on corn snake territory size, the findings for this subspecies can only be tentatively applied to the species as a whole. (Sperry and Taylor, 2008)

Communication and Perception

Corn snakes have rather poor eyesight and depend mainly on olfaction to perceive their environment. Like other snakes, their tongues, in conjunction with the Jacobson's organ in the roof of the mouth, detect scent molecules in the surrounding environment. In addition to the presence of these scents, corn snakes can also determine the direction from which the molecules were released. Corn snakes can also feel ground vibrations throughout their body, which are used to locate small or otherwise hidden prey or predators. Although they have no external ears, snakes have well-developed, functioning inner ears. When sound waves contact a snake's skin, the vibration is conducted through the bones of the jaw to the cochlea. Each of the jaws functions independent of the other in this respect, effectively allowing stereo hearing and directional sound location. (Friedel, et al., 2008; Mattison, 2007; Zug, et al., 2001)

Corn snakes communicate in the same ways as most other species of snake. During the mating season, males give off pheromones that are detected by females. Communication is rare outside of mating season, as they are solitary animals. (Mattison, 2007)

Food Habits

Corn snakes are carnivorous and do not need to eat often. They eat every few days in the wild. They kill prey by constriction and consume anything smaller than they are, including other corn snakes. Over half of their diet consists of rodents such as hispid cotton rats, white-footed mice and other mammal prey, such as eastern moles. In Florida, their diet consists mainly of reptiles and amphibians, which this may be a cause for this region's smaller snake sizes. Corn snakes will also climb trees and swallow bird eggs from unguarded nests. (Bartlett and Bartlett, 2005; Ernst and Barbour, 1989; Sievert, et al., 2005; Stake, et al., 2005)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • eggs

Predation

Corn snakes have few natural predators, mostly larger snakes and birds of prey. Carnivorous mammals may also eat corn snakes. Larger snakes, such as eastern kingsnakes and black racers, will consume corn snakes. A corn snake’s primary method of avoiding predators is by camouflage and fleeing from danger. Juveniles hide from predators under tree bark. (Bartlett and Bartlett, 2005; Mattison, 2007)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

The biggest impact that corn snakes have on their ecosystem is their ability to control populations of small mammals and birds. Several species of apicomplexan parasites infect corn snake blood cells, liver, and lung tissue. Hepatozoon guttata (named for its host) is thought to be exclusive to red corn snakes and has been identified in individuals from southeast Florida. It is not known how the parasites spread from individual to individual. (Kimbell III, et al., 1999; Mattison, 2007; Plutzer and Karanis, 2007; Telford, et al., 2002)

Commensal/Parasitic Species
  • Hepatozoon guttata (Order Eucoccidiorida, Phylum Apicomplexa)
  • Cryptosporidium serpentis (Order Eucoccidiorida, Phylum Apicomplexa)
  • Cryptosporidium saurophilum (Order Eucoccidiorida, Phylum Apicomplexa)

Economic Importance for Humans: Positive

Like many snake species, corn snakes play a vital role in controlling rodent populations, helping to prevent the spread of disease and crop damage in areas inhabited by humans. Corn snakes are also popular pets for reptile enthusiasts. Breeders have developed a variety of color morphs for the pet market. They are easy to care for if proper attention is paid to setting up their terrarium (dry, clean, with an area set up for them to bask under a heat lamp) and are generally safe for families with children. As pets, corn snakes are fed high protein diets consisting mainly of mice and rats, although day-old chicks have been shown to provide similar nutrition. (Arbuckle, 2010; Bartlett and Bartlett, 2005; Mattison, 2007)

  • Positive Impacts
  • pet trade
  • controls pest population

Economic Importance for Humans: Negative

Although a corn snake's preferred defense is to flee, cornered snakes will bite humans. (Bartlett and Bartlett, 2005)

  • Negative Impacts
  • injures humans
    • bites or stings

Conservation Status

Although some natural habitat has been lost to human development, corn snakes show no sign of being a threatened species. (Hammerson, 2012)

Other Comments

This species was formerly known as Elaphe guttata. Recent phylogenetic studies have suggested that the name Pantherophis guttatus should be applied to this species, New World rat snakes appear to be more closely related to species of the tribe Lampropeltini (which includes kingsnakes) rather than Old World rat snakes (for which the generic name Elaphe still applies). (Pyron and Burbrink, 2009; Utiger, et al., 2002)

Contributors

Sarah Hogrefe (author), Radford University, Karen Powers (editor), Radford University, Kiersten Newtoff (editor), Radford University, Melissa Whistleman (editor), Radford University, Jeremy Wright (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

acoustic

uses sound to communicate

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

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

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.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

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).

native range

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

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.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynous

having more than one female as a mate at one time

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

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

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.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

vibrations

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

visual

uses sight to communicate

year-round breeding

breeding takes place throughout the year

References

Arbuckle, K. 2010. Suitability of day-old chicks as food for captive snakes. Journal of Animal Physiology and Animal Nutrition, 94/6: 296-307.

Bartlett, R., P. Bartlett. 2005. Guide and Reference to the Snakes of Eastern and Central North America (North of Mexico). Gainesville, Florida: University Press of Florida.

Burbrink, F. 2002. Phylogeographic analysis of the cornsnake (Elaphe guttata) complex as inferred from maximum likelihood and Bayesian analyses. Molecular Phylogenetics and Evolution, 25/3: 465-476.

Conant, R., J. Collins. 1998. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. New York, NY: Houghton Mifflin Company.

Ernst, C., R. Barbour. 1989. Snakes of Eastern North America. Fairfax, Virginia: George Mason University Press.

Friedel, P., B. Young, J. van Hemmen. 2008. Auditory Localization of Ground-Borne Vibrations in Snakes. Physical Review Letters, 100/4: 4 pages.

Hammerson, G. 2012. "Pantherophis guttatus" (On-line). The IUCN Red List of Endangered Species. Accessed February 07, 2012 at http://www.iucnredlist.org/apps/redlist/details/63863/0.

Kimbell III, L., D. Miller, W. Chavez, N. Altman. 1999. Molecular analysis of the 18S rRNA gene of Cryptosporidium serpentis in a wild-caught corn snake (Elaphe guttata guttata) and a five-species restriction fragment length polymorphism-based assay that can additionally discern C. parvum from C. wrairi. Applied and Environmental Microbiology, 65/12: 5345-5349.

Mattison, C. 2007. The New Encyclopedia of Snakes. Princeton, New Jersey: Princeton University Press.

Plutzer, J., P. Karanis. 2007. Molecular identification of a Cryptosporidium saurophilum from corn snake (Elaphe guttata guttata). Parisatology Research, 101/4: 1141-1145.

Pyron, R., F. Burbrink. 2009. Neogene diversification and taxonomic stability in the snake tribe Lampropeltini (Serpentes: Colubridae). Molecular Phylogenetics and Evolution, 52: 524-529.

Seigel, R., N. Ford. 1991. Phenotypic plasticity in the reproductive characteristics of an oviparous snake, Elaphe guttata: Implications for life history studies. Herpetologica, 47/3: 301-307.

Sievert, L., D. Jones, M. Puckett. 2005. Postprandial thermophily, transit rate, and digestive efficiency of juvenile cornsnakes, Pantherophis guttatus. Journal of Thermal Biology, 30/5: 354-359.

Sperry, J., C. Taylor. 2008. Habitat use and seasonal activity patterns of the Great Plains ratsnake (Elaphe guttata emoryi) in central Texas. The Southwestern Nautralist, 53/4: 444-449.

Stake, M., F. Thompson, J. Faaborg, D. Burhans. 2005. Patterns of snake predation at songbird nests in Missouri and Texas. Journal of Herpetology, 39/2: 215-222.

Stewart, J., T. Ecay, D. Blackburn. 2004. Sources and timing of calcium mobilization during embryonic development of the corn snake, Pantherophis guttatus. Comparative Biochemistry and Physiology, 139/3: 335-341.

Telford, S., J. Butler, R. Telford. 2002. Hepatozoon species (Apicomplexa: Hepatozoidae) of the corn snake, Elaphe guttata (Serpentes: Colubridae) and the pigmy rattlesnake, Sistrurus miliarius barbouri (Serpentes: Viperidae) in south Florida. The Journal of Parasitology, 88/4: 778-782.

Utiger, U., N. Helfenberger, B. Schätti, C. Schmidt, M. Ruf, V. Ziswiler. 2002. Molecular systematics and phylogeny of old and new world rat snakes, Elaphe Auct., and related genera (Reptilia, Squamata, Colubridae). Russian Journal of Herpetology, 9/2: 105-124.

Zug, G., L. Vitt, J. Caldwell. 2001. Herpetology, Second Edition: An Introductory Biology of Amphibians and Reptiles. San Diego, CA: Academic Press.

de Magalhaes, J., J. Costa. 2009. A database of vertebrate longevity records and their relation to other life-history traits. Journal of Evolutionary Biology, 22/8: 1770-1774.

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