Posts Tagged ‘Crotalus adamateus’

The Orianne Indigo Snake Preserve

May 1, 2013

It’s too late to save most of North America’s megafauna.  Man overhunted most of the magnificent animals on this continent into extinction thousands of years ago, and Europeans nearly eradicated the rest within historical times.  But it’s not too late to save an apex predator of the southeastern coastal plain–the indigo snake (Drymarchon couperi).  A private charitable group, the Orianne Indigo Snake Society, is purchasing land and negotiating with other large landholders to manage their property for the benefit of this snake.  Their goal is to protect 48,704 acres of land within the Orianne Indigo Snake Preserve.  Presently, they own 2,607 acres and have permission to manage an additional 8,678 more acres (mostly owned by lumber companies) for the benefit of the snake.  This seems like a lot of land, but male indigo snakes require as much as 3000 acres of habitat because they are top predators, in fact predators of predators.

Images from the Orianne Snake Society website.

The preserve is located along the Ocmulgee River where there are many sandhills.

Indigo snake range map.  They were extirpated from Alabama decades ago.

Orianne Society volunteer with an indigo snake.  Strippers like to use indigo snakes in their acts because they are long and docile, seldom biting humans.  It’s the largest North American species of snake.

Indigo snakes require 2 different types of habitat.  During winter they den in gopher tortoise burrows located in open pine savannahs with sandy soils, but during summer they forage in shaded bottomland swamps.  They need access to both environments unobstructed by manmade structures, such as busy roads where automobiles take a heavy toll.  Modern day development makes areas with vast acreages of both types of habitat rare.  Moreover, open pine savannahs have been replaced with pine tree farms which are inadequate habitats for gopher tortoises.  Indigo snakes can survive on pine tree farms without gopher tortoises, as long as the lumber operators leave refuse piles for the snakes to seek refuge during colder months.  Indigo snakes also make use of armadillo dens and hollow logs.  The Orianne Society manages habitat by conducting prescribed burns which improve habitat for gopher tortoises, and by encouraging lumber operators to leave debris piles.

Indigo snakes were extirpated from Alabama.  Indigo snakes are a major predator of venomous snakes, and copperhead populations skyrocketed in Alabama, since indigo snakes disappeared there.  The Orianne Society has a captive breeding program.  Two years ago, they began releasing indigo snakes in the Conecuh National Forest in Covington County, Alabama.  Eventually, this may help reduce copperhead populations.

Indigo snakes are primarily forage hunters, though ambush hunting has been recorded.  They actively travel over land and capture other animals, especially snakes.  They bite their prey and thrash and bash the animal into submission.  One study found that 85% of their diet included gopher tortoises, snakes, and rodents.  They are immune to rattlesnake poison and commonly feed upon diamondback rattlesnakes.  They are cannibalistic, so human breeders of captive indigoes keep them in separate enclosures.  They also scavenge.  One was observed feeding on a dead shark, and they will eat fish in captivity.  Scientists suspect indigo snakes feed on fish stranded in shrinking pools during droughts, much like cottonmouth water moccasins do.   Another individual was observed ambushing 5 rufous-sided sparrows by a single puddle when the birds came to drink and bathe.  These behaviors show they are both active and passive feeders.  They’re big eaters despite being cold blooded reptiles.  A species of indigo snake native to Central America was observed feeding on a boa constrictor, then on a jumping viper before the former was digested.

There are 5 species of indigo snakes in the Drymarchon genus.  In addition to the one that lives in North America, 4 species live in Central and South America.  The genus is closely related to black racers.

The Orianne Indigo Snake Preserve protects several species of big snakes.  The indigo snake frequently grows to 7.5 feet long with a record length of 8.5 feet, but this only beats the record length of the coachwhip snake (Masticophis flagellum) by 1.5 inches.   Diamondback rattlesnakes (Crotalus adamateus) have been known to reach a length of 8 feet long, and pine snakes (Pituophis melanaleucus) get to 5 feet long.

Diamondback rattlesnakes grow to 8 feet long but occasionally fall prey to indigos.

Coachwhip snakes get their name because they are shaped just like a whip.  They are almost as long as indigos but are much skinnier.  They come in many different color variations.

Rainbow snakes (Farancia erystrogramma) grow to 3-4 feet long.  These snakes are also found on the Orianne Indigo Snake Preserve.  They burrow in sand and mud in swamps.  They specialize in feeding on eels.

By contrast southeastern crown snakes reach lengths of just 10 inches.  They specialize in feeding upon centipedes.  There are 3 species which diverged following sea level rises that isolated founding populations.

Fort Stewart has some of the best remaining habitat for big coastal plain snakes.  Here, the federal government is free to conduct prescribed burns that improve wildlife diversity, plus there are fewer roads and no real estate development on the base.  Live fire exercises on this and other army bases in Georgia also improve habitat for wildlife by igniting fires.  More species of snakes have been recorded from Fort Stewart than any other area of the state–33 species.  So far, just 21 species of snakes are known to occur on the Orianne Indigo Snake Preserve, but as this area becomes better studied that number will grow.  Fort Stewart is home to bald eagles, wood storks, and healthy populations of wood ducks, fox squirrels, deer, and wild boar.  If this military base is ever closed, I hope it’s protected as a wildlire preserve.

Most North American snakes have been recorded in the Pleistocene and Pliocene fossil records, and scientists think most of today’s existing snake genuses originated early in the Miocene.  Snakes are an ancient part of the ecosystem, and it would be a shame, if we lost any individual species.


Stevenson, Dirk; et. al.

“Prey Records for the eastern Indigo Snake (Drymarchon couperi)”

Southeastern Naturalist 9 (1) 2010