Pantherophis guttatus

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.

• Biogeographic Regions
• nearctic nearctic
  • native native

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.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest

• Other Habitat Features
• suburban suburban

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.

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.

• Other Physical Features
• heterothermic heterothermic

• Sexual Dimorphism
• male larger

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).

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.

• Development - Life Cycle
• indeterminate growth indeterminate growth

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.

• Mating System
• polygynous polygynous

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.

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.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• year-round breeding year-round breeding
• sexual sexual
• fertilization fertilization
• oviparous oviparous

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.

• 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.

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.

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.

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.

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.

• Key Behaviors
• terricolous
• diurnal diurnal
• crepuscular crepuscular
• sedentary sedentary
• hibernation hibernation
• solitary solitary

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.

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.

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.

• Communication Channels
• tactile tactile
• chemical chemical

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical

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.

• Primary Diet
• carnivore 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.

• Anti-predator Adaptations
• cryptic 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.

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.

• Positive Impacts
• pet trade 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.

• 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.

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).

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

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.

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.