The Eastern Indigo Snake (Drymarchon couperi) is a large, non-venomous reptile native to the southeastern United States. Contrary to common misconceptions, these snakes are not poisonous and pose no threat to humans. They are recognized for their generally docile temperament.
Identifying Indigo Snakes
The Eastern Indigo Snake is recognized by several distinct physical characteristics. It is the longest native snake species in the United States, commonly reaching 5 to 7 feet, with some individuals exceeding 8.5 feet. These snakes possess a robust and heavy-bodied build.
A prominent feature is their uniformly glossy, bluish-black scales that exhibit a striking iridescent purple or blue sheen in sunlight. This unique coloration gives the snake its common name. While most of their scales are smooth, adult males may display subtle keels, or ridges, on some scales along the middle of their back.
Another distinguishing mark is the coloration of their chin, throat, and sometimes the sides of their head, which can range from reddish-orange to cream, white, or black in certain populations. These features help differentiate the Eastern Indigo Snake from other dark-colored snakes in its habitat, such as the thinner black racer or the patterned black rat snake.
Habitat and Natural Behavior
The Eastern Indigo Snake inhabits a diverse range of environments across the southeastern United States. These snakes are found in pine flatwoods, sandhills, dry forests, scrub, and agricultural fields.
For shelter, Eastern Indigo Snakes frequently use existing underground burrows, particularly those created by gopher tortoises. These burrows are important in the northern parts of their range, providing refuge from cold temperatures during winter. They also utilize other natural shelters such as armadillo holes, hollow logs, and root channels.
As apex predators, Eastern Indigo Snakes consume a variety of animals, including other snakes, small mammals, birds, frogs, lizards, turtles, and their eggs. Notably, they prey on venomous snakes like rattlesnakes and cottonmouths, as they possess an immunity to their venom. Unlike constrictors, they overpower their prey by using their powerful jaws or pressing the victim against a hard surface.
When encountered, Eastern Indigo Snakes display a docile temperament. They are not aggressive towards humans and prefer to escape or remain still rather than engage in confrontation.
Conservation Status and Encounters
The Eastern Indigo Snake is federally protected as a threatened species under the Endangered Species Act. This protection extends to state levels, with the species also listed as threatened in Florida and Georgia, and as endangered in Alabama and Mississippi.
Factors contributing to their imperiled status include habitat loss, degradation, and fragmentation from urban development and agricultural expansion. These snakes require large, unfragmented territories, with a single individual potentially utilizing up to 805 acres. Other threats include illegal collection for the pet trade, mortalities from vehicle strikes, and the illegal practice of “gassing” gopher tortoise burrows to flush out rattlesnakes, which inadvertently harms indigo snakes.
If you encounter an Eastern Indigo Snake, observe it from a respectful distance. Never attempt to touch, handle, or capture it, as such actions are illegal under federal and state laws and can harm the snake.
Understanding their ecological role helps support their survival. You can contribute to conservation efforts by reporting sightings, ideally with photographs, to state wildlife agencies like the Florida Fish and Wildlife Conservation Commission or the U.S. Fish and Wildlife Service.