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This page will be completely different from the other pages of species' accounts. First, I will leave it almost completely unaltered from when Mike originally constructed this site. He did I bettert, and put more work into it, that I could ever have done.
Second, due to the variation throughout the state, I will present this in a way that I can display the variation with the locality. The text here will include natural history and background on the current taxonomic status. For those people not familiar with the variation in Louisiana, my suggestion is to read the text, then go to the range map which contains thumbnails that will have links to larger photos.
The corn snake in Louisiana is a story all by itself. East of the Mississippi River, which is only a small portion of the state, identification of this species is easy. West of the Mississippi River it gets a little confusing sometimes. The problem here is that Louisiana is the crossroads for the corn snake and the Great Plains rat snake. To complicate matters, if it is found in central Louisiana, it can be either a corn snake Elaphe guttata, a Great Plains rat snake Elaphe emoryi, or an intergrade, depending on the source you choose to use or agree with. On this page I will not present an argument one way or another as to the correct taxonomic identity of this snake, but will list sources that I am aware of as to each case. For the purpose of this page, the term "corn snake" will apply, regardless of the argument for a particular generic name.
Argument for Elaphe guttata ssp.:
Vaughan, Kathryn R., Dixon, James R., and Thomas, Robert A. (1996) A reevaluation of populations of the corn snake elaphe guttata (reptilia: serpentes: colubridae) in texas. The Texas Journal of Science - Vol. 48, No. 3, 175-190.
Note: This is currently the most commonly accepted classification of corn snake and is older than the other form.
These authors do not recognize Elaphe emoryi as a species. They recognize only one species and three subspecies. They show Elaphe guttata meahllmorum in south Texas, Elaphe guttata emoryi in central and north Texas, and Elaphe guttata guttata in east Texas on into Louisiana. These findings were based on data accumulated from 337 specimens, 51 of which were from Louisiana. The others were from Texas and Oklahoma. Many characteristics were counted for the snakes including body blotches, tail blotches, ventrals, subcaudals body blotches plus tail blotches, ventrals plus subcaudals, ventral pigmentation and subcaudal stripes. For E.g.guttata they showed a body blotch range of 32-42, tail blotches (11-18), ventrals (206-234), subcaudals (61-74). Eighty-one percent showed heavy ventral pigmentation and 90.9% had the presence of subcaudal stripes. There are a lot of numbers in the paper. For comparisons please refer to the source. They also refer to L. R. Raymond and L. M. Hardy noting that "typical" Elaphe guttata guttata west of the Mississippi River are from the parishes of Iberia, Point Coupee and West Baton Rouge.
Argument for Elaphe emoryi:
Walls, J. G. (March 1998). That other corn snake. Reptile Hobbyist, p 69.
Jerry Walls considers the corn snakes in central Louisiana to be Elaphe emoryi. He states that there is a 50 mile wide corridor in Louisiana that no corn snakes are known. He believes that this is a dividing line that separates the two species, since they do not intergrade in this "zone." This is one factor in which he forms his opinion that those east of the Mississippi River are Elaphe guttata and those west of the Mississippi River are Elaphe emoryi.
Note: Jerry Walls also makes an argument for the corn snakes to be in the genus Pantherophis. This is based on the work of J. Scott Keogh, published in Herpetologica, 53(3).
Argument for intergrades:
Dundee, H. A., and Rossman, D. A. (1989). The Amphibians and Reptiles of Louisiana. LSU Press. p. 231.
"Elaphe g. guttata is generally thought to occur in and adjacent to the Florida Parishes and along the western margin of the lower Atchafalaya Basin, and to intergrade with E. g. emoryi in central Louisiana". They also conclude that they believe a case could be made for considering those from extreme northwestern Louisiana to be Elaphe guttata emoryi.
Another theory about the evolution of this "species"
in Louisiana is that the corn snakes from the east were
intergrading with the Great Plains (Emory's) rat snakes from the
west. When the habitat changed in central Louisiana, it cut
them off from the gene pools of the "pure" animals and
only the intergrades survived. Once these animals were isolated
they began to change from the parental stock on each side,
eventually leading to a distinct population of snakes. This is a
plausible theory that would make an interesting study.
Source: KJ Lodrigue, Jr.
The corn snake has slightly different habits that other Elaphe in Louisiana. They are primarily terrestrial and only occasionally climb. As with many species of snakes, they seem to be encountered most frequently in the spring on roads at night. In Louisiana they seem to be primarily occupants of forested areas. In my experience looking for them in central Louisiana, they seem to lead a mostly subterranean life. They are nearly impossible to find while walking through suitable habitat and looking under cover. This usually only yields Elaphe obsoleta. DOR's are frequently found and most live specimens are obtained by riding the roads just after dark.
Louisiana is not well known for it's corn snakes as far as trade is concerned. The mention of corn snakes makes many people think of Florida or South Carolina. It was once thought that the populations were relatively low in Louisiana even where they did occur. However, because of an increase in collecting activity and vehicular road traffic in rural areas, it is now known that some areas can have dense populations. I have seen some truly outstanding individuals found here. I have seen several DOR's in Evangeline parish in south central Louisiana that had very intense orange with thick, jet black borders around the blotches. Central Louisiana, just west of Alexandria can also produce some very nice "Kisatchie corns."
This is just the basics of the corn snake in Louisiana. If anyone who reads this can supply me with additions or corrections, please e-mail them, with or without photos.
I would like to thank KJ Lodrigue, Jr., of KJUN Snakehaven in Baton Rouge for reviewing this page and providing me with a lot of his thoughts, ideas, and most importantly, for being a good friend. He is an excellent source for information about corn snakes in Louisiana. His web site is primarily about the animals he breeds and sells and has little on the topic of classification and natural history of the corn snake. He is a grad student at LSU and is doing some work with the species and e-mailing him would be the best way to find out more about the corn snakes in Louisiana. Here are links to his web site and e-mail address:
I would also like to thank Theron Magers of Boyce. It was his "Kisatchie corns" that got me interested in the species on the state level. He has provided me with valuable locality data and has exposed me to some of the phenotypically different corn snakes in Louisiana.
Please send comments and/or questions to firstname.lastname@example.org
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