Corn snake

Corn snake
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Genus: Pantherophis
Species: P. guttatus
Binomial name
Pantherophis guttatus
(Linnaeus, 1766)
Synonyms
A close up portrait
Gravid female
Young corn snake

The corn snake (Pantherophis guttatus) is a North American species of rat snake that subdues its small prey by constriction.[4][5] It is found throughout the southeastern and central United States. Their docile nature, reluctance to bite, moderate adult size, attractive pattern, and comparatively simple care make them popular pet snakes. Though superficially resembling the venomous copperhead and often killed as a result of this mistaken identity, corn snakes are harmless and beneficial to humans.[6] Corn snakes lack functional venom and help control populations of wild rodent pests that damage crops and spread disease.[7]

The corn snake is named for the species' regular presence near grain stores, where it preys on mice and rats that eat harvested corn.[8] The Oxford English Dictionary cites this usage as far back as 1675. Some sources maintain that the corn snake is so-named because the distinctive, nearly-checkered pattern of the snake's belly scales resembles the kernels of variegated corn.[9][10] Regardless of the name's origin, the corn reference can be a useful mnemonic for identifying corn snakes.

Description

Adult corn snakes have a body length of 61–182 centimetres (2.00–5.97 ft).[11] In the wild, they usually live around 6–8 years, but in captivity can live to an age of 23 years or more.[12] They can be distinguished from Copperhead snakes by their brighter colors, slender build and lack of heat-sensing pits.[13]

Taxonomy

Until 2002, the corn snake was considered to have two subspecies: the nominate subspecies (Pantherophis guttatus guttatus) described here and the Great Plains rat snake (Pantherophis guttatus emoryi). The Great Plains rat snake has since been split off as its own species (Pantherophis emoryi), but is still occasionally treated as a subspecies of the corn snake by hobbyists.

It has been suggested that Pantherophis guttatus can be split into three species: Pantherophis guttatus, Pantherophis emoryi (corresponding with the subspecies Pantherophis guttatus emoryi) and Pantherophis slowinskii (occurring in western Louisiana and adjacent Texas).[14]

Pantherophis guttatus was previously placed in the genus Elaphe, but Elaphe was found to be paraphyletic by Utiger et al., leading to placement of this species in the genus Pantherophis.[15] The placement of Pantherophis guttatus and several related species in Pantherophis rather than Elaphe has been confirmed by further phylogenetic studies.[16][17] Many reference materials still use the synonym Elaphe guttata.[18] Molecular data has shown that corn snakes are actually more closely related to king snakes (genus Lampropeltis) than they are to the Old World rat snakes with which they were formerly classified. Corn snakes have even been bred in captivity with California king snakes to produce fertile hybrids known as "Jungle corn snakes".[19]

Natural habitat

Wild corn snakes prefer habitats such as overgrown fields, forest openings, trees, palmetto flatwoods and abandoned or seldom-used buildings and farms, from sea level to as high as 6,000 feet. Typically, these snakes remain on the ground until the age of 4 months old but can ascend trees, cliffs and other elevated surfaces.[20] They can be found in the southeastern United States ranging from New Jersey to the Florida Keys and as far west as Texas.

In colder regions, snakes hibernate during winter. However, in the more temperate climate along the coast they shelter in rock crevices and logs during cold weather, and come out on warm days to soak up the heat of the sun. During cold weather, snakes are less active and therefore hunt less.

Reproduction

Baby corn snakes hatching from their eggs

Corn snakes are relatively easy to breed. Although not necessary, they are usually put through a cooling (also known as brumation) period that takes 60–90 days. This is to get them ready for breeding and to tell them that its time to reproduce. Corns brumate at around 10 to 16 °C (50 to 61 °F) in a place where they can not be disturbed and with little sunlight.

Corn snakes usually breed shortly after the winter cooling. The male courts the female primarily with tactile and chemical cues, then everts one of his hemipenes, inserts it into the female, and ejaculates his sperm. If the female is ovulating, the eggs will be fertilized, and she will begin sequestering nutrients into the eggs, then secreting a shell.

Egg-laying occurs slightly more than a month after mating, with 12–24 eggs deposited into a warm, moist, hidden location. Once laid the adult snake abandons the eggs and does not return to them. The eggs are oblong with a leathery, flexible shell. Approximately 10 weeks after laying, the young snakes use a specialized scale called an egg tooth to slice slits in the egg shell, from which they emerge at about 5 inches in length.

Diet and behavior

Captive corn snake eating young mouse

Like all snakes, corn snakes are carnivorous, and in the wild they eat every few days. While most corn snakes will eat small rodents, such as the White-footed Mouse, they may also eat reptiles or amphibians, or climb trees to find unguarded bird eggs.[21] Behavioral/chemosensory studies with corn snakes suggest that odor cues are of primary importance for prey detection, whereas visual cues are of secondary importance.[22][23] Like many species of Colubridae, corn snakes exhibit tail vibrating.[24]

It has been found that the American "rat snakes", such as Pantherophis guttatus, had venomous ancestors which lost their venom after they evolved constriction as a means of prey capture.[25]

In captivity

Corn snakes are one of the most popular types of snakes to keep in captivity or as pets. Their size, calm temperament, and ease of care contribute to this popularity. Captive corn snakes tolerate being handled by their owners, even for extended periods.[26] A corn snake's space requirements are low since a 25-gallon vivarium provides enough room for a fully grown snake. Corn snakes enjoy hiding and burrowing, usually accommodated with a loose substrate (such as Aspen wood shavings or newspaper) and one or more hide boxes.[27] Captive corn snakes are generally fed pre-killed or stunned feeder mice, because captive-bred rodents reduce the risk of pathogens or live prey-induced injuries.[28]

Variations

A docile young corn snake (an introduced species) captured from the wild on the island of Nevis, West Indies, in 2009.

After many generations of selective breeding, domesticated corn snakes are found in a wide variety of different colors and patterns. These result from recombining the dominant and recessive genes that code for proteins involved in chromatophore development, maintenance, or function. New variations, or morphs, become available every year as breeders gain a better understanding of the genetics involved.

Color morphs

An anerythristic corn snake

Pattern morphs

Amelanistic Stripe corn snake

Compound morphs

There are tens of thousands of possible compound morphs. Some of the most popular are listed.

"Opal" phase corn snake

Scale mutations

Hybrids

Hybrids between corn snakes and any other snakes is very common within captivity and rarely occurs in the wild. Hybrids within the genera Pantherophis, Lampropeltis, or Pituophis so far have been proven to be completely fertile. There are many different corn snake hybrids bred in captivity. A few common examples include:

When hybrids of corn snakes are found in the wild they are usually hybridized with other Pantherophis species whose ranges overlap with corn snakes.

References

  1. Hammerson, G.A. (2007). "Pantheropis guttatus". IUCN Red List of Threatened Species. Version 2015.3. International Union for Conservation of Nature. Retrieved 22 September 2015.
  2. Stejneger L, Barbour T. 1917. A Check List of North American Amphibians and Reptiles. Cambridge, Massachusetts: Harvard University Press. iv + 125 pp. (Elaphe guttata, p. 82).
  3. "Pantheropis guttatus". The Reptile Database.
  4. Crother, B. I. (2012). "Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding" (PDF). Society for the Study of Amphibians and Reptiles Herpetological Circular. 39: 1–68.
  5. Bealor, M.T. and Saviola, A.J., 2007. Behavioural complexity and prey-handling ability in snakes: gauging the benefits of constriction. Behaviour, 144(8), pp.907-929. http://dx.doi.org/10.1163/156853907781492690
  6. "Corn Snake".
  7. "Did Someone Say Snakes?".
  8. "FLMNH - Eastern Corn Snake (Pantherophis guttatus)".
  9. PetCo Corn Snake Care Sheet
  10. Smithsonian National Zoo Corn Snake Fact Sheet
  11. "Corn Snake Fact sheet". Smithsonian National Zoological Park.
  12. Slavens, Frank; Slavens, Kate. "Elaphe guttata guttata".
  13. "Reptiles and Amphibians of Virginia". Virginia Herpetological Society.
  14. Burbrink, F. T., 2002. Phylogeographic analysis of the corn snake (Elaphe guttata) complex as inferred from maximum likelihood and Bayesian analyses. Molecular Phylogenetics and Evolution 25: 465-476.
  15. Utiger, U., N. Helfenberger, B. Schätti, C. Schmidt, M. Ruf, and V. Ziswiler, 2002. Molecular Systematics and Phylogeny of Old and New World ratsnakes, Elaphe Auct., and related genera (Reptilia, Squamata, Colubridae). Russian Journal of Herpetology 9(2): 105-124.
  16. Burbrink, F. T. and R. Lawson, 2007. How and when did Old World rattle snakes disperse into the New World? Molecular Phylogenetics and Evolution 43: 173-189.
  17. Pyron, R. A. and F. T. Burbrink, 2009. Neogene diversification and taxonomic stability in the snake tribe Lampropeltini (Serpentes: Colubridae) Molecular Phylogenetics and Evolution 52: 524-529.
  18. Bartlett, Patricia; Bartlett, R. D. (2006-05-26), Corn Snakes and Other Rat Snakes, Complete Pet Owner's Manual (2nd ed.), Hauppauge NY: Barron's Educational Series, ISBN 978-0-7641-3407-4
  19. http://banereptiles.weebly.com/jungle-corn-snakes.html
  20. Peterson Field Guide - Western Reptiles and Amphibians - 3rd Edition
  21. "ADW: Pantherophis guttatus: INFORMATION". University of Michigan Museum of Zoology.
  22. Saviola, A.J., McKenzie, V.J. and Chiszar, D., 2012. Chemosensory responses to chemical and visual stimuli in five species of colubrid snakes. Acta Herpetologica, 7(1), pp.91-103. http://dx.doi.org/10.13128/Acta_Herpetol-9491
  23. Worthington-Hill, J.O., Yarnell, R.W. and Gentle, L.K., 2014. Eliciting a predatory response in the eastern corn snake (Pantherophis guttatus) using live and inanimate sensory stimuli: implications for managing invasive populations. International Journal of Pest Management, 60(3), pp.180-186. http://dx.doi.org/10.1080/09670874.2014.953230
  24. Allf, Bradley C., Paul AP Durst, and David W. Pfennig. "Behavioral Plasticity and the Origins of Novelty: The Evolution of the Rattlesnake Rattle." The American Naturalist 188.4 (2016): 475-483
  25. Fry et al. 2012.
  26. "The Corn Snake.co.uk".
  27. "The Corn Snake.co.uk - Care Sheet".
  28. "Corn Snake Care Sheet". South Mountain Reptiles.
Wikispecies has information related to: Pantherophis guttatus
Wikimedia Commons has media related to Pantherophis guttatus.
Wikimedia Commons has media related to Elaphe guttata.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.