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Ophisaurus compressus Cope, 1900
Island Glass Lizard
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G3G4
State Rank: S2
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: Moderate Conservation Concern
Element Occurrences (EOs) in Georgia: 15
Habitat Summary for element in Georgia: Pine savannas, pine flatwoods, secondary dunes/interdunal swales on islands
This is a long, slender, limbless lizard that reaches a maximum total length of 61 cm (23.8 in). Approximately two-thirds of this length is represented by their very long tail, unless it has been shortened by injury. Like all four Georgia glass lizard species, this form superficially looks like a snake. The scales of island and other glass lizards are reinforced with tiny plates known as osteoderms, which make them considerably more rigid than snakes. This and other glass lizards are further distinguished from snakes by their small belly scales, moveable eyelids, external ear openings, and a fold of skin (called the lateral fold) that extends along the side from the neck to the vent. Island glass lizards are cream or yellow in overall color and have a bold, chocolate-brown stripe on each side of the body above the lateral fold that extends down most of the tail’s length. A similarly-colored mid-dorsal stripe is also present, but in some individuals it is broken-up into a series of dashes. The belly is unmarked and light yellow to pinkish. Older males often have scattered bars or speckling on the back and sides. Hatchlings average 14 cm (5.5 in) in total length.
Mimic glass lizards (O. mimicus) are similar in size but lack the prominent single, dark stripe on each side of the body above the fold that extends onto the tail. Mimics, as well as the other two much larger native glass lizards (eastern [O. ventralis] and slender [O. attenuatus]; reaching total lengths in excess of 100 cm [39.4 in]), have multiple thin, dark lines on the tail. Counting scale rows is the most reliable way of distinguishing island glass lizards from smaller individuals of the latter two species; fewer than 97 scale rows are present along the lateral fold of islands, while greater than 97 are found on eastern and slender glass lizards. Unlike the other three glass lizards, island glass lizards do not have fracture planes in their tail vertebrae, which makes their tail less vulnerable to breakage and leaves them more likely to be found with complete tails.
Populations on coastal islands are usually associated with grassy, early successional habitats formed in secondary dune systems. Some individuals may be found using tidal wrack for shelter. Pine flatwoods provide suitable habitat for these lizards on the mainland.
Prey items include insects, spiders, and other invertebrates.
Island glass lizards mate during spring, and lay 4-18 eggs per clutch approximately six weeks later. Females attend the eggs, which take about six weeks to incubate and hatch.
Visual pedestrian surveys are often effective at locating individuals in appropriate habitats on the islands. Individuals on the mainland are most likely to be encountered while crossing roads, or while lying dead on roads. Drift fence arrays equipped with funnel traps may be effective at intercepting and capturing island glass lizards.
Island glass lizards range from coastal South Carolina south through most of the Florida peninsula. Recent observations of this species in Georgia have been exclusively from sea islands and other coastal areas, but records also exist from throughout the Okefenokee basin.
Relatively few observations of this species have been made recently in Georgia, especially inland, suggesting that it may be in decline. Habitat loss is a likely threat in mainland populations, but most of the island populations occur on protected lands. The impact of sea level rise caused by climate change on this species is unknown but may be of concern.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Natural system modifications | Climate change & severe weather | Residential & commercial development |
| Specific Threat | None | None | None |
Protected populations are known from Sapelo Island, Little St. Simons Island, and Okefenokee National Wildlife Refuge.
Populations occurring in mainland pine flatwoods and savannas should be managed with periodic fire or other techniques that favor dense grassy groundcover and limit hardwoods and tall shrubs. Intensive soil disturbance should be avoided. Very little is known about this species’ natural history, thus research is sorely needed to help understand the full spectrum of its needs and threats.
Bartlett, R. D.1985. Notes on the natural history and reproductive strategy of the island glass lizard, Ophisaurus compressus. British Herpetological Society Bulletin 11:19-21.
Holman, J. A. 1971. Ophisaurus compressus. Catalogue of American Amphibians and Reptiles 113:1-2.
Moler, P. E. 2008. Island Glass Lizard: Ophisaurus compressus. Pp. 283-284 In Jensen, J. B., C. D. Camp, W. Gibbons, and M. J. Elliott (eds.). Amphibians and Reptiles of Georgia. University of Georgia Press, Athens. 575 p.
John B. Jensen
4/10/18