Eastern Indigo Snake - Florida Museum

NON-VENOMOUS

Other common names

Gulf Coast Indigo Snake, Indigo Snake, Racer

Basic description

Most adult Eastern Indigo Snakes are about 60-82 inches (152-213 cm) in total length. These large and thick-bodied snakes are glossy black and have iridescent purple or blue highlights when viewed in sunlight. The chin and throat are typically red or orangish, and the color may extend down the body. Juveniles are glossy black with narrow whitish-blue bands.

Range in Florida

Eastern Indigo Snakes are found throughout Florida. They appear to still occur in the Florida Keys, though sightings there are extremely rare.

Assessment of risk to people and pets

Non-venomous. Eastern Indigo Snakes are not dangerous to people or pets. These snakes are not aggressive and avoid direct contact when possible.

Comparison with other species

North American Racer (Coluber constrictor) Non-venomous North American Racers are smaller and they have thinner bodies. They also typically have a white chin and throat, and the black coloration of their bodies is duller.

Eastern Coachwhip (Masticophis flagellum) Non-venomous Eastern Coachwhips typically have a black head and neck and a tan body and tail.

Detailed Description

Most adult Eastern Indigo Snakes are 60-82 inches (152-213 cm) in total length, with a record length recorded of 8.6 feet (2.63 m). These large and thick-bodied snakes are glossy black and have iridescent purple or blue highlights when viewed in sunlight. The chin and throat may be solid black, red, orangish, or cream-colored, and the color may extend down the body. The belly is cloudy black to blueish-gray, sometimes with reddish-orange or white anteriorly. The scales on the back are smooth, and there are 17 scale rows at midbody. The pupil is round. Juveniles are glossy black with narrow whitish-blue bands.

Habitat

Eastern Indigo Snakes occupy a wide range of habitats including scrub, tropical hardwood hammocks, pine flatwoods, prairies, coastal dunes, and the edges of freshwater marshes and cypress ponds. They also occupy various types of agricultural lands. They are commonly associated with Gopher Tortoise (Gopherus polyphemus) burrows, which they often use as refuges.

Defensive behavior

If cornered or captured, Eastern Indigo Snakes will seldom bite in defense. However, they may flatten their neck vertically, hiss loudly, rapidly vibrate the tip of the tail, which produces a buzzing sound in leaf litter, and release a foul-smelling musk from a pair of glands in the base of the tail.

Diet and feeding behavior

Eastern Indigo Snakes have a generalist diet and likely eat any vertebrate small enough for them to overpower and swallow. These snakes appear to prefer to eat other reptiles (including venomous snakes), but they are known to also eat amphibians, mammals, and birds. These snakes are not constrictors and overpower their prey by grabbing it in their jaws, pressing it against the ground, and chewing it until it stops struggling or by quickly swallowing it alive.

Reproduction

In Florida, females lay around 4-14 eggs, which typically hatch between July and September. Hatchlings average 22 inches (55 cm) in total length.

Comments

No subspecies are currently recognized in Florida.

Eastern Indigo Snakes were listed as state threatened by the State of Florida in 1975, and in 1978 they were federally listed as threatened by the U.S. Fish and Wildlife Service.

Two studies published in 2016 indicated that indigo snakes in Florida represent two distinct lineages. As a result, the range of the eastern indigo snake was restricted to areas along the Atlantic coast. Indigo snakes throughout the rest of Florida were designated as the second lineage and given the new name Drymarchon kolpobasileus (the Gulf Coast Indigo Snake). However, the recognition of two distinct species of indigo snakes in Florida is not widely accepted. This is largely due to two subsequent studies published in 2019 using different analyses and additional data that strongly suggest all indigo snakes in Florida belong to a single species, the Eastern Indigo Snake. As such, we consider all indigo snakes in Florida to be Eastern Indigo Snakes, but we realize that this remains contentious and that analyses of additional data may later support the presence of two distinct species.

Florida counties with confirmed records

County data coming soon.

If you have a new or interesting observation for this species, please email the herpetology staff at the Florida Museum.

References and further reading

Ernst, C.H. and E.M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Institution Press, Washington, DC. 668 pp.

Folt, B., J. Bauder, S. Spear, D. Stevenson, M. Hoffman, J.R. Oaks, P.L. Wood, Jr., C. Jenkins, D.A. Steen, and C, Guyer. 2019. Taxonomic and conservation implications of population genetic admixture, mito-nuclear discordance, and male-biased dispersal of a large endangered snake, Drymarchon couperi. PLoS ONE 14(3): e0214439. https://doi.org/10.1371/journal.pone.0214439

Krysko, K.L., K.M. Enge, and P.E. Moler. 2019. Amphibians and Reptiles of Florida. University of Florida Press, Gainesville, Florida. 706 pp.

Krysko, K.L., M.C. Granatosky, L.P. Nuñez, and D.J. Smith. 2016. A cryptic new species of Indigo Snake (genus Drymarchon) from the Florida Platform of the United States. Zootaxa 4138(3): 549–569.

Powell, R., R. Conant, and J.T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Fourth edition. Houghton Mifflin Harcourt Publishing Company, Boston and New York. xiv + 494 pp.

Share your observations

You can help scientists better understand the biology and distribution of this species by sharing your observations. Send photos or videos of interesting observations, along with associated information, by emailing the herpetology staff at the Florida Museum for documentation in the Museum’s Herpetology Master Database. You can also post your observations on iNaturalist.

Additional helpful information

Do you have snakes around your house? Learn how to safely co-exist with snakes.

Still have questions about snakes or identifications? Feel free to email the herpetology staff at the Florida Museum with your questions or feedback on this profile.

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