Corn snake

The corn snake (Pantherophis guttatus), sometimes called red rat snake is a species of North American rat snake in the family Colubridae. The species subdues its small prey by constriction. It is found throughout the southeastern and central United States. Though superficially resembling the venomous copperhead (Agkistrodon contortrix) and often killed as a result of this mistaken identity, the corn snake lacks functional venom and is harmless. The corn snake is beneficial to humans because it helps to 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 (maize). The Oxford English Dictionary cites this usage as far back as 1675, whilst other 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.
The genus name Panthērophis literally means "panther snake" in reference to the snake's panther-like skin pattern; from Ancient Greek: πάνθηρ : pánthēr "panther", and Ancient Greek: ὄφις : óphis "snake".
The species name is from Latin: guttatus meaning "spotted, speckled", again in reference to the snake's skin pattern.
As an adult the corn snake may have a total length (including tail) of 61–182 cm (2.00–5.97 ft). In the wild, it usually lives around ten to fifteen 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. The natural corn snake is usually orange or brown bodied with large red blotches outlined in black down their backs. The belly has distinctive rows of alternating black and white marks. This black and white checker pattern is similar to Indian corn (maize) which is where the name corn snake may have come from. The corn snake can be distinguished from a copperhead by the corn snake's brighter colors, slender build, slim head, round pupils, and lack of heat-sensing pits.
Until 2002, the corn snake was considered to have two subspecies: the nominate subspecies (P. g. guttatus) described here and the Great Plains rat snake (P. g. emoryi). The latter has since been split off as its own species (P. emoryi), 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 (P. guttatus), the Great Plains rat snake (P. emoryi, corresponding with the subspecies P. g. emoryi), and Slowinski's corn snake (P. slowinskii, occurring in western Louisiana and adjacent Texas).
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 in Elaphe has been confirmed by further phylogenetic studies. Many reference materials still use the synonym Elaphe guttata. Molecular data have shown that the corn snake is actually more closely related to kingsnakes (genus Lampropeltis) than it is to the Old World rat snakes (genus Elaphe) with which it was formerly classified. The corn snake has even been bred in captivity with the California kingsnake (Lampropeltis californiae) to produce fertile hybrids known as "jungle corn snakes".
In the wild, the corn snake prefers 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 ft (1,800 m). Typically, the corn snake remains on the ground until the age of four months but can ascend trees, cliffs, and other elevated surfaces. It can be found in the Southeastern United States ranging from New Jersey to the Florida Keys.
In colder regions, the corn snake brumates during winter. However, in the more temperate climate along the coast, it shelters in rock crevices and logs during cold weather. It 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, the corn snake is less active so it hunts less.
Often called the "American corn snake", guttatus is a proscribed pest in much of Australia. There are active extermination campaigns and advice for the public in Victoria, New South Wales, and Queensland.
It has been found that corn snakes (along with other colubrids) reach sexual maturity by means of size, as opposed to age.
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 to get them ready for breeding. Corn snakes brumate around 10 to 16 °C (50 to 61 °F) 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 (13 cm) long.
Reproduction in captivity has to be done correctly so the clutch's mortality rate decreases. This includes accurate sexing, establishing proper pre-breeding conditioning, and timely pairing of adults. Corn snakes are temperate zone colubrids, and share a reproductive pattern where females increase their feeding during summer and fall. This only applies to corn snakes that are sexually mature, which typically indicates the snake is around 75 cm (30 inches) in length or weight 250 g.
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.
Seasons play a large role in the thermal regulation patterns of corn snakes, which is the main mechanism of digestion for snakes. During fall, corn snakes maintain a body temperature approximately 3 degrees Celsius higher than the surrounding environment after consuming a meal, while corn snakes in the winter are not seen to thermoregulate after digestion. Captive snakes do this by using heat mats as an underneath heat source replicates their natural conditions. Corn snakes demonstrate nocturnal patterns, and use the warm ground at night to thermoregulate, therefore heat mats replicate this source.
American "rat snakes", such as P. guttatus, had venomous ancestors, which lost their venom after they evolved constriction as a means of prey capture.
Like many species of the Colubridae, corn snakes exhibit defensive tail vibration behavior. Behavioral and chemosensory studies with corn snakes suggest that odor cues are of primary importance for prey detection, whereas visual cues are of secondary importance.
A study conducted by Dr. David Holzman of the University of Rochester in 1999 found that snakes' capacity for spatial learning rivals those of birds and rodents. Holzman challenged the typical testing method that was being used by biologists to examine snakes' navigational abilities, claiming the structure of the arena itself was biologically in favor of rodents. He hypothesized that if the typical arena being used to test the animals was modified to cater to snakes' instinctive goals, thus providing them with problem sets that they would likely encounter in their natural environment, this would give a more accurate view of their intelligence.
The study involved testing 24 captive-bred corn snakes, placing them in an open tub with walls too high for them to climb out. Eight holes were cut out underneath, with one hole leading to a shelter. An intense light was positioned to shine directly on the arena, exploiting the snake's natural aversion to bright open spaces. This provided a biologically meaningful objective for the snakes: to seek out cozy dark shelter.
The study found that when given the incentive of finding shelter, the snakes exhibited an acute ability to learn and navigate their surroundings. They also found snakes rely on their sense of vision much more than many herpetologists had previously assumed. They found that younger snakes were able to more quickly locate the holes than older snakes, as the younger snakes were more resourceful in their application of senses and older snakes relied more heavily on their sense of sight.
Arboreal movement is poorly understood, despite many snakes like the Corn Snake being an arboreal species. A study conducted Henry C. Astley and Bruce C. Jayne from the University of Cincinnati found that Corn Snakes (Elaphe guttata) had three qualitative features resembling tunnel concertina locomotion: alternating bends to the left and right, stopping periodically, and some portion of the body always having static contact with the substrate.
Four adult corn snakes with similar snout–vent lengths, total lengths, mid-body lateral diameters, and masses were placed on different perches. The perches were seven different cylinders (diameters 1.6–21cm) with five inclines (horizontal, ±45° and ±90°).
Results indicated that when perches were placed at 45° or 90°, snakes were unable to move uphill or downhill only on the larger diameter cylinders. Additionally, on horizontal and uphill perches the corn snakes used concertina locomotion of stopping and gripping. On downhill movement, the snakes slid numerously and would have to grasp the perch to reduce speed. When looking at tunnels, the tunnel width barely affected the speeds of concertina locomotion.
Corn snakes are one of the most popular types of snakes to keep in captivity or as pets, second only to the ball python. Outside of their native range, they are a popular pet snake in Brazil, where they risk becoming an invasive species. 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.
After many generations of selective breeding, captive bred 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.
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.
In this snake Snake fungal disease (SFD) is caused by Ophidiomyces ophiodiicola.