Key ringneck snake: Diadophis punctatus acricus

Taxonomic Classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Colubridae
Genus/Species: Diadophis punctatus
Subspecies: Diadophis punctatus acricus
Common Name: Key ringneck snake

Listing Status

Federal Status: Not Listed
FL Status: State-designated Threatened
FNAI Ranks: G5T1Q/S1 (Globally: Demonstrably Secure, Sub sp. Critically Imperiled [subspecies classification questioned]/State: Critically Imperiled)
IUCN Status: Not ranked

Physical Description

The Key ringneck snake is one of the smallest species of the Family Colubridae  (Bartlett and Bartlett 2003).  Body length can range from 3.5 to 10 inches (8.9-25.4 centimeters).  This species has a grayish-black back, yellow to red belly, pale grayish-brown head, reddish-orange tail, and a poorly defined or missing neck ring (Florida Natural Areas Inventory 2001). 

Life History

The diet of the Key ringneck snake primarily consists of small amphibians, lizards, snakes, insects, slugs, and earthworms (Ernst and Ernst 2003).

Little is known about the reproduction of the Key ringneck snake.  With most ringneck snakes, they will lay one to ten eggs per clutch while having the ability to lay more than one clutch per year (Ernst and Ernst 2003).

Habitat and Distribution

Key Ringneck Snake Distribution MapKey ringneck snakes inhabit tropical hardwood hammocks and scrub. This species is restricted to the Lower Keys and has been found on Key West and Big Pine, Little Torch, Middle Torch, and No Name Keys (Weaver et al. 1992, Auth and Scott 1996, museum records)


The Key ringneck snake faces considerable threats to its population, such as the destruction of its habitat.  The clearing of pine rockland and rockland hammocks can cause a decline in the population, especially when the habitats are near freshwater sources.  This species also faces the danger of being hit by cars, especially in extensive networks of roads on Big Pine Key.  Storm surge, short-term flooding, and a rising sea level can also contribute to declining Key ringneck snake populations.  The prey of Key ringneck snakes can also be affected by floodwaters, as most would not be able to escape floods that would inundate their habitat.  Other threats include increased predation on the Key ringneck snake by species such as the invasive red imported fire ant (Mount 1981).

Conservation and Management

The Key ringneck snake is protected as a State-designated Threatened species by Florida’s Endangered and Threatened Species Rule External Website.

Biological Status Review (BSR) Adobe PDF
Supplemental Information for the BSR Adobe PDF

Other Informative Links

Florida Museum of Natural History External Website
Florida Natural Areas Inventory External Website



Printable version of this page Adobe PDF


Auth, D. L., and C. Scott. 1996. Geographic distribution: Diadophis punctatus acricus (Key ringneck snake). Herpetological Review 27:33.

Bartlett, R. D., and P. Bartlett. (2003). Florida Snakes: A Guide to Their Identification and Habits. Gainesville, Florida: University Press of Florida.  182 pp.

Ernst, C. H., and E. M. Ernst.  2003.  Snakes of the United States and Canada.  Smithsonian Books, Washington, D.C., USA.  668pp.

Florida Museum of Natural History.  (n.d.).  Key Ringneck Snake.  Retrieved April 4, 2011, from Herpetology: External Website

Florida Natural Areas Inventory.  2001.  Field guide to the rare animals of Florida.   External Website

Mount, R. H. 1981. The red imported fire ant, Solenopsis invicta (Hymenoptera: Formicidae), as a possible serious predator on some native southeastern vertebrates: direct observations and subjective impressions.  Journal of the Alabama Academy of Science 52:71–78.

Weaver, W. G., S. P. Christman, and P. E. Moler. 1992. Big Pine Key ringneck snake, Diadophis punctatus acricus Paulson. Pages 146–149 in P. E. Moler, editor. Rare and endangered biota of Florida. Volume III. Amphibians and reptiles. University Press of Florida, Gainesville, Florida, USA.

Image Credit Photo by Kevin Enge, FWC

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