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WILDLIFE SPECIES:  Drymarchon couperi
Eastern indigo snake. U.S. Army, Creative Commons image.


WILDLIFE SPECIES: Drymarchon couperi
AUTHORSHIP AND CITATION : Snyder, S. A. 1993. Drymarchon couperi. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: []. Revisions : On 23 Ocotber 2015, the common and scientific names of this species were changed from: indigo snake, Drymarchon corais to: eastern indigo snake, Drymarchon couperi. Citations were added [15,16] to support the changes.
ABBREVIATION : DRCO COMMON NAMES : indigo snake American corais snake blue bull snake blue gopher snake Couper's snake Georgia snake TAXONOMY : The currently accepted scientific name for the eastern indigo snake is Drymarchon couperi (Holbrook) (Colubridae) [15,16]. The Texas indigo snake a separate species (Drymarchon melanurus) [16] and is not covered in this review. ORDER : Squamata CLASS : Reptile SYNONYMS : Drymarchon corais (Holbrook)[11,14] Drymarchon corais corais (Boie) [14] Drymarchon corais couperi (Holbrook)[11] FEDERAL LEGAL STATUS : The eastern indigo snake is federally listed as Threatened [13]. OTHER STATUS : The eastern indigo snake is in decline throughout its range [9,17]. The state of Florida lists it as threatened [12].


WILDLIFE SPECIES: Drymarchon couperi
GENERAL DISTRIBUTION : The eastern indigo snake ranges from southern South Carolina south through Florida and west to Mississippi [11, 17]. ECOSYSTEMS : FRES12 Longleaf-slash pine FRES13 Loblolly-shortleaf pine FRES16 Oak-gum-cypress FRES41 Wet grasslands STATES :
BLM PHYSIOGRAPHIC REGIONS : None KUCHLER PLANT ASSOCIATIONS : K079 Palmetto prairie K080 Marl - everglades K091 Cypress savanna K092 Everglades K112 Southern mixed forest K113 Southern floodplain forest K115 Sand pine scrub K116 Subtropical pine forest

SAF COVER TYPES : 70 Longleaf pine 71 Longleaf pine - scrub oak 72 Southern scrub oak 81 Loblolly pine 82 Loblolly pine - hardwood 84 Slash pine 85 Slash pine - hardwood 89 Live oak 104 Sweetbay - swamp tupelo - redbay 105 Tropical hardwoods 111 South Florida slash pine 241 Western live oak SRM (RANGELAND) COVER TYPES : 808 Sand pine scrub 810 Longleaf pine-turkey oak hills 811 South FLorida flatwoods 812 North Florida flatwoods 813 Cutthroat seeps 814 Cabbage palm flatwoods 815 Upland hardwood hammocks 816 Cabbage palm hammocks 817 Oak hammocks 820 Everglades flatwoods 821 Pitcher plant bogs
Longleaf pine woodland, an eastern indigo snake habitat. Photo by Chuck Bargeron, University of Georgia,

The eastern indigo snake is most abundant in the sandhill plant communities of
Florida and Georgia.  These communities are primarily scrub oak-longleaf
pine (Pinus palustris) with occasional live oak (Quercus virginiana),
laurel oak (Q. laurifolia), Chapman's oak (Q. chapmanii), and myrtle oak
(Q. myrtifolia).  Other communities include longleaf pine-turkey oak (Q.
laevis), slash pine (Pinus elliottii)-scrub oak, pine flatwoods, and
pine-mesic hardwoods [1].


WILDLIFE SPECIES: Drymarchon couperi
TIMING OF MAJOR LIFE HISTORY EVENTS : Eastern indigo snakes can grow as long as 125 inches (262 cm). They mate from November through March with a peak in mid-November through late December. The age of sexual maturity is unknown [9]. An average of 3 to 10 eggs are laid in March through July; eggs hatch from May through October [10]. The average life span of the eastern indigo snake is 11 years, although they can live as long as 21 years [11]. They do not hibernate and remain somewhat active during winter, especially if temperatures are higher than 50 degrees Fahrenheit (10 deg C) [9]. PREFERRED HABITAT : Eastern indigo snakes frequent flatwoods, hammocks, dry glades, stream bottoms, cane fields, riparian thickets, and high ground with well-drained, sandy soils [11]. In Georgia, snakes prefer excessively drained, deep sandy soils along major streams, as well as xeric sandridge habitats [1]. Xeric slash pine plantations seem to be preferred over undisturbed longleaf pine habitats [6]. Habitat selection varies seasonally. From December to April eastern indigo snakes prefer sandhill habitats; from May to July snakes shift from winter dens to summer territories; from August through November they are located more frequently in shady creek bottoms than during other seasons [9]. COVER REQUIREMENTS : Because the cover requirements of eastern indigo snakes change seasonally, maintaining corridors that link the different habitats used is important. From the spring through fall snakes must be able to travel from sandhill communities and upland pine-hardwood communities to creek bottoms and agricultural fields [9]. In winter eastern indigo snakes den in gopher tortoise burrows, which are usually found in open pine forests with dense herbaceous understories [6]. Burrows need to be in areas where there is no flooding. Eastern indigo snakes also heavily use debris piles left from site-preparation operations on tree plantations [6]. These piles are often destroyed for cosmetic reasons but should be left intact because they provide important hiding cover for both the snake and its prey. Summer home ranges for the eastern indigo snake can be as large as 273 acres (229 ha) [9]. FOOD HABITS : Eastern indigo snakes eat other snakes, turtles, lizards, frogs, toads, a variety of small birds and mammals, and eggs [6,11]. PREDATORS : Humans represent the biggest threat to eastern indigo snakes. Highway fatalities, wanton killings, and overcollection for the pet trade adversely affect eastern indigo snake populations. Snakes are taken illegally from the wild and sold as petsi. Snakes are also inadvertantly gassed in their burrows by rattlesnake hunters [1]. MANAGEMENT CONSIDERATIONS : Eastern indigo snakes are a commensal species associated with gopher tortoises. Snakes use abandoned tortoise burrows heavily in the winter and spring [1]. For this reason it is necessary to maintain healthy tortoise populations, also a species in decline throughout its range. Because slash piles are used by snakes for hiding and foraging, this debris should be left intact on pine plantations [6]. Speake and others [9] recommend protecting several thousand hectares of prime eastern indigo snake habitat to ensure the snakes' year-round needs are met. Some important sandhill communities of Georgia and Florida are being replaced by slash pine plantations, which can support a few snakes if burned and planted with wide spacing to encourage gopher tortoise populations [6]. Recommendations for captive breeding of eastern indigo snakes are as follows [10]: Captive snakes should be released to the wild after 2 to 3 years, and new snakes from the wild should be introduced to the captive population, preferably every winter. This is important because wild snakes seem to grow faster and produce more young than snakes held in captivity. Because smaller snakes do not use tortoise burrows, they should be released in wetland areas with plenty of herbaceous cover near the water's edge. Hatchlings will den in areas with dense saw palmetto (Serenoa repens) and should be released near these areas.


WILDLIFE SPECIES: Drymarchon couperi
DIRECT FIRE EFFECTS ON ANIMALS : Because hatchlings do not use tortoise burrows they may be susceptible to fire mortality. However, adult snakes may be able to escape fires while in their burrows [10]. HABITAT RELATED FIRE EFFECTS : Fire exclusion in southern pine-scrub oak habitats is a major cause of habitat degredation for gopher tortoise and, therefore, eastern indigo snakes [6]. The absence of fire allows oaks to mature and leaf litter to accumulate, making burrow digging difficult and herbaceous food scarce. Studies of herpetofauna in Florida sandhill commmunities showed higher species diversity in young sand pine (Pinus clausa)-scrub oak habitats, which are maintained by frequent fire [7]. Experimental burns in these communities showed snakes used plots burned at 2- and 7-year intervals more than plots left unburned or burned yearly. The effects of different season burns on gopher tortoises in Ocala National Forest, Florida, showed more burrows in July-burned areas than in February-burned areas at the first postfire year [8]. Preburn densities of gopher tortoise were not determined. FIRE USE : Landers and Speake [6] recommend burning eastern indigo snake habitats every 2 years to maintain a young, open overstory and an abundant herbaceous understory. This will provide good gopher tortoise habitat, which in turn will provide burrows for snakes. Burning sandhill communities every 2 to 4 years will maintain open longleaf pine stands with understories of wiregrass (Aristida stricta) and turkey oak [6]. Burning in late summer where young eastern indigo snakes have been released from captive breeding programs is not recommended because young snakes depend on dense herbaceous vegetation for cover instead of burrows [10]. FIRE REGIMES : Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".


WILDLIFE SPECIES: Drymarchon couperi
REFERENCES : 1. Diemer, Joan E.; Speake, Dan W. 1983. The distribution of the eastern indigo snake, Drymarchon corais couperi, in Georgia. Journal of Herpetology. 17(3): 256-264. [21093] 2. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 3. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998] 4. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 5. Landers, J. Larry. 1987. Prescribed burning for managing wildlife in southeastern pine forests. In: Dickson, James G.; Maughan, O. Eugene, eds. Managing southern forests for wildlife and fish: a proceedings; [Date of conference unknown]; [Location of conference unknown]. Gen. Tech. Rep. SO-65. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station: 19-27. [11562] 6. Landers, J. Larry; Speake, Dan W. 1980. Management needs of sandhill reptiles in southern Georgia. Proceedings, Annual Conference of Southeast Association Fish & Wildlife Agencies. 34: 515-529. [21092] 7. Mushinsky, Henry R. 1985. Fire and the Florida sandhill herpetofaunal community: with special attention to responses of Cnemidophorus sexlineatus. Herpetologica. 41(3): 333-342. [11953] 8. Robbins, Louise E.; Myers, Ronald L. 1992. Seasonal effects of prescribed burning in Florida: a review. Misc. Publ. No. 8. Tallahassee, FL: Tall Timbers Research, Inc. 96 p. [21094] 9. Speake, Dan W.; McGlincy, Joe A.; Colvin, Thagard R. 1978. Ecology and management of the eastern indigo snake in Georgia: a progress report. In: Odum, R. R.; Landers, L., eds. Proceedings, Rare and endangered wildlife symposium. Tech. Bull. WL4. Atlanta, GA: Georgia Department of Natural Resources, Game and Fish Division: 64-73. [21090] 10. Speake, Dan; McGlincy, Donna; Smith, Cynthia. 1987. Captive breeding and experimental reintroduction of the eastern indigo snake. In: Proceedings, 3rd Southeast nongame and endangered wildlife symposium: 84-88. [21091] 11. Conant, Roger; Collins, Joseph T. 1991. A field guide to reptiles and amphibians: Eastern and central North America. 3rd ed. Peterson Field Guide Series No. 12. Boston: Houghton Mifflin Company. 450 p. [22902] 12. Wood, Don A., compiler. 1994. Official lists of endangered & potentially endangered fauna and flora in Florida. Tallahassee, FL: Florida Game and Fresh Water Fish Commission. 22 p. [24196] 13. U.S. Department of the Interior, Fish and Wildlife Service. 2016. Endangered Species Program, [Online]. Available: [86564] 14. ITIS Database. 2015. Integrated taxonomic information system, [Online]. Available: [51763] 15. Collins, Joseph T. 1991. Viewpoint: a new taxonomic arrangement for some North American amphibians and reptiles. Herpetological Review. 22(2): 42-43. [89439] 16. Crother, Brian I., Chair. 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Herptelogical Circular No. 39. Shoreview, MN: Society for the Study of Amphibians and Reptiles. 92 p. [88775] 17. NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life, [Online]. Version 7.1. Arlington, VA: NatureServe (Producer). Available: [69873]

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