The Eastern Indigo Snake Returns

The longest snake native to the United States, the eastern indigo, grows 9 feet long. The apex predator is sleek as a stair banister, with conspicuous black-blue scales. It’s non-venomous and, at least as far as its diet goes, fond of its fellow snakes, particularly the venomous kind. A daytime hunter, it was once a common sight throughout Florida, Georgia, southern Alabama and southeastern Mississippi. By 1978, however, its numbers had so drastically declined, victim to human antipathy, cars and the steady degradation of its habitat. The eastern indigo was one of the earliest entries on the list of protected wildlife under the Federal Endangered Species Act.

Before reintroduction, eastern indigos had been noticeably absent at TNC’s Apalachicola Bluffs and Ravines Preserve (ABRP) since the last ones were spotted in 1982. As an apex predator, the species plays a vital role in the natural balance, a consumer of otherwise unchecked species, especially snakes. Many endemic species at ABRP, particularly songbirds, have likely suffered from the imbalance.

When the first 12 zoo-raised eastern indigos were released at ABRP in 2017, it symbolized a significant milestone for a partnership 35 years in the making that, in addition to TNC, included, the Central Florida Zoo & Botanical Gardens’ Orianne Center for Indigo Conservation, the Florida Fish and Wildlife Conservation Commission (FWC), U.S. Fish and Wildlife Service, Welaka National Fish Hatchery, The Orianne Society, Joseph W. Jones Ecological Research Center, Southern Company through the National Fish and Wildlife Foundation, and the Fish & Wildlife Foundation of Florida.

Year 5 Update—2021:
Twelve Eastern Indigo Snakes Reintroduced

In 2021, an additional 12 snakes were released, bringing the total to 81 since the reintroduction began. The 12 two-year old snakes released at ABRP were bred and hatched by OCIC. All hatched in 2019, the four females and eight males were raised for one year at the OCIC, and transferred to the Welaka National Fish Hatchery for an additional year in preparation for their release. The snakes have been implanted with passive integrated transponders (PIT-tags) by the Central Florida Zoo's veterinary staff to allow for identification when encountered after release.

Year 4 Update—2020:
22 Eastern Indigo Snakes Reintroduced

In 2020, an additional 22 snakes were released, bringing the total to 69 since the reintroduction began. In the first three years of the effort, Auburn University’s Alabama Natural Heritage Program conducted onsite monitoring of the reintroduced snakes, including the initial 32 snakes which were released were implanted with radio transmitters, allowing researchers to track the animals’ movements. One of the eastern indigo snakes that was released in 2017 traveled over a mile from where it was initially released.

Ideal Protected Habitat for Indigo Snakes

Apalachicola Bluffs and Ravines Preserve was not an arbitrary choice for the reintroduction of the eastern indigo snake. Originating, poetically enough, with a tract of land called the Garden of Eden, the preserve today is one of Florida conservation’s greatest success stories. After 35 years of restoration efforts by TNC and its partners, it is now a fully restored Florida  longleaf pine landscape, a vast forest system that once flourished throughout the state, north to Virginia and west to Southern Texas, but is now reduced to only 5 percent of its original map.

“Patient restoration efforts, including groundcover restoration, prescribed burns and replanting, have fully restored the ABRP, part of a region that is now considered one of the five most important biological hotspots in North America,” said David Printiss, TNC North Florida Program Manager.

A lush mosaic of habitats, the preserve is forested with pines, cut with ravines and streams, and carpeted in mile after mile of waving wiregrass. As this flora returned, so did the gopher tortoises, bobwhite quail and Florida pine snakes. The only missing piece was the eastern indigo.

Indigo Snake Captive Breeding Program

Bred and raised by Central Florida Zoo’s Orianne Center for Indigo Conservation (OCIC), each reintroduced eastern indigo snake was tagged with a subcutaneous radio transmitter and a Passive Integrated Transponder (PIT) tag. The tags help scientists measure survival rate, reproduction, preferred habitats and the distance the snakes cover. The data from the tags is monitored full time by scientists at Auburn University in Alabama.

“Auburn has a long history with eastern indigos, dating back to the 1970s, including two earlier reintroductions in Alabama,” said David Steen, assistant research professor overseeing the monitoring program.

In the next 10 years, the plan is to release approximately 300 eastern indigos into the preserve, said Michele Elmore, lead biologist for the U.S. Fish and Wildlife Service. In year 3 of our snake release program in June 2019 fifteen snakes were released. View our efforts in the gallery below.

“For the first time in a long time, other parts of the Panhandle are being restored to the point that they, too, will be ready for reintroductions,” she said. “Our ultimate goal is to establish and protect enough viable populations so that we can remove the eastern indigo from the list of protected wildlife.”