Eastern indigo snake

EasternIndigoSnake.jpg

Eastern indigo snake: Drymarchon corais couperi

Taxonomic Classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Colubridae
Genus/Species: Drymarchon corais
Subspecies: Drymarchon corais couperi
Common Name: Eastern indigo snake

Listing Status

Federal Status: Threatened
FL Status: Federally-designated Threatened
FNAI Ranks: G4T3/S3 (Globally: Apparently Secure, Sub sp. Rare/State: Rare)
IUCN Status: LC (Least Concern)

Physical Description

The Eastern indigo snake is a non-venomous, bluish-black colored snake that can reach lengths of eight feet (2.4 meters).  Its chin, cheek, and throat are mostly red or brown, but can also be white or black.  Most indigo snakes have smooth scales, although adults do have keels (ridges) on the front of some of their scales (Florida Natural Areas Inventory 2001).  When approached, the Eastern indigo snake shows no aggression (L. Nester pers. comm. 2011).  They are also exothermic species – their body temperature is externally regulated.

Life History

The Eastern indigo snake’s diet primarily consists of a variety of species, including small mammals, birds, toads, frogs, turtles and their eggs, lizards, and small alligators (National Park Service, n.d.). 

Indigo snakes begin breeding between the months of November and April and nest between the months of May and August.  Females lay 4-12 eggs yearly or bi-yearly, with the eggs hatching 90 days after being laid.  Since the indigo snake is a commensal of the gopher tortoise, females usually deposit their eggs in gopher tortoise burrows.  Females may have the ability to hold sperm, which would allow them to defer fertilization of an egg.  Parthenogenesis (a form of asexual reproduction) may also be possible with Eastern indigo snakes, as some virginal snakes have been seen laying eggs (Kendrick and Mengak 2010, Smithsonian Marine Station at Fort Pierce, n.d.). 

Habitat and Distribution

Eastern Indigo Snake Distribution Map

Eastern indigo snakes inhabit pine flatwoods, hardwood forests, moist hammocks, and areas that surround cypress swamps.  They can be found throughout Peninsular Florida and southeastern Georgia (Florida Museum of Natural History, n.d.).

Threats:

The main threats facing the Eastern indigo snake is habitat destruction, fragmentation, and degradation.  Habitat destruction is caused mainly by the extension of urban development in their habitat.  Indigo snakes lose more than 5% of their habitat each year in Florida (Kendrick and Mengak 2010).  As a species that often occupies gopher tortoise burrows, indigo snakes face being injured by people hunting for rattlesnakes in the burrows.  This action usually causes death to other species in the burrow including Easter indigo snakes.  Habitat degradation is also a result from this action.  Habitat fragmentation is also a threat as increased housing and road development can separate their habitat into smaller individual habitats.  Small fragmented habitats can have problems supporting a viable population.  Other threats include pollutants, vehicle strikes, captures for domestication, and intentional killings (Kendrick and Mengak 2010, Florida Natural Areas Inventory 2001).

Conservation and Management

The Eastern indigo snake is protected as a Threatened species by the Federal Endangered Species Act and as a Federally-designated Threatened species by Florida’s Endangered and Threatened Species Rule External Website.

Federal Recovery Plan External Website
Federal Action Plan External Website

Other Informative Links

Species Profile: Eastern Indigo Snake
Broward College External Website
Florida Museum of Natural History External Website
Florida Natural Areas Inventory External Website
International Union for Conservation of Nature External Website
National Park Service External Website
Smithsonian Marine Station at Fort Pierce External Website
State of Alabama Forestry Commission External Website
Tallahassee Museum External Website
University of Georgia - Featured Herp in the Big Cypress National Preserve External Website
University of Georgia - Eastern Indigo Publication External Website
U.S. Army Environmental Command External Website
U.S. Fish and Wildlife Service External Website
Zoo America External Website

 

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References

Florida Museum of Natural History. (n.d.). Eastern indigo snake, indigo snake, racer. Retrieved   May 23, 2011, from Herpetology: http://www.flmnh.ufl.edu/herpetology/fl-guide/Drymarchoncouperi.htm External Website

Florida Natural Areas Inventory.  2001.  Field guide to the rare animals of Florida. http://www.fnai.org/fieldguide/pdf/drymarchon_couperi.pdf External Website

Kendrick, M. M., & Mengak, M. T. (2010, September). Eastern Indigo Snake (Drymarchon couperi). Retrieved May 23, 2011, from The Warnell School of Forestry and Natural Resources: http://www.forestry.uga.edu/outreach/pubs/pdf/NHS10-12.pdf External Website

National Park Service. (n.d.). Eastern Indigo Snake: Species Profile. Retrieved May 23, 2011, from Everglades National Park: http://www.nps.gov/ever/naturescience/easternindigosnake.htm External Website

Smithsonian Marine Station at Fort Pierce. (n.d.). Drymarchon couperi. Retrieved May 23, 2011, from North American Mammals: http://www.sms.si.edu/irlspec/drymar_couper.htm External Website


Image Credit Photo by FWC



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