Corn snake


The corn snake is a North American species of rat snake that subdues its small prey by constriction. 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 commonly kept 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. Corn snakes lack functional venom and help control populations of wild rodent pests that damage crops and spread disease.
The corn snake is named for the species' regular presence near grain stores, where it preys on mice and rats that eat harvested corn. 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. 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. In the wild, they usually live around six to eight years, but in captivity can live to an age of 23 years or more. The record for the oldest corn snake in captivity was 32 years and 3 months. They can be distinguished from copperheads by their brighter colors, slender build, round pupils, and lack of heat-sensing pits.

Taxonomy

Until 2002, the corn snake was considered to have two subspecies: the nominate subspecies described here and the Great Plains rat snake. The latter has since been split off as its own species, but is still occasionally treated as a subspecies of the corn snake by hobbyists.
P. guttatus has been suggested to be split into three species: the corn snake, the Great Plains rat snake and Slowinski's corn snake.
P. 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. The placement of P. guttatus and several related species in Pantherophis rather than Elaphe has been confirmed by further phylogenetic studies. Many reference materials still use the synonym Elaphe guttata. Molecular data have shown that corn snakes are actually more closely related to kingsnakes 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 kingsnakes to produce fertile hybrids known as "jungle corn snakes".

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 four months, but can ascend trees, cliffs, and other elevated surfaces. They can be found in the Southeastern United States ranging from New Jersey to the Florida Keys.
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; they also can find shelter in small, closed spaces, such as under a house, and come out on warm days to soak up the heat of the sun. During cold weather, snakes are less active, so they hunt less.

Reproduction

Corn snakes are relatively easy to breed. Although not necessary, they are usually put through a cooling period that takes 60–90 days to get them ready for breeding. Corn snakes brumate around in a place where they cannot 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 leathery, flexible shells. About 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 in long.

Diet and behavior

Like all snakes, corn snakes are carnivorous and in the wild, they eat every few days. While most corn snakes eat small rodents, such as the white-footed mouse, they may also eat other reptiles or amphibians, or climb trees to find unguarded bird eggs. Behavioral / chemosensory studies with corn snakes suggest that odor cues are of primary importance for prey detection, whereas visual cues are of secondary importance. Like many species of the Colubridae, corn snakes exhibit defensive tail vibration behavior.
American "rat snakes", such as P. guttatus, had venomous ancestors, which lost their venom after they evolved constriction as a means of prey capture.

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.

Variations

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

There are tens of thousands of possible compound morphs. Some of the most popular ones are listed here.
Hybrids between corn snakes and any other snake is very common in captivity, but rarely occurs in the wild. Hybrids within the genera Pantherophis, Lampropeltis, or Pituophis so far have been proven to be completely fertile.
Many different corn snake hybrids are bred in captivity. A few common examples include:
When hybrids of corn snakes are found in the wild, they have usually hybridized with other Pantherophis species whose ranges overlap with corn snakes.