Reptiles of North Carolina
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NC Records

Liodytes rigida - Glossy Swampsnake

Liodytes rigida
Photo: C. Helms, H. Leonard		Liodytes rigida
Photo: E. Hofmann, K. Weinfurther		Liodytes rigida
Photo: E. Hofmann, K. Weinfurther
Taxonomy
Class: Reptilia Order: Serpentes Family: Colubridae Subfamily: Natricinae Synonym: Regina rigida Other Common Name(s): Glossy Crayfish Snake
Taxonomic Comments: Liodytes, as currently considered, consists of three species of small to medium-sized semiaquatic snakes native to the southeastern United States.
Species Comments: Liodytes rigida, the Glossy Swampsnake, is one of two Liodytes in North Carolina. This species is found in the southeastern United States from southeastern Virginia to Florida, and west to east Texas. In North Carolina, L. rigida is restricted primarily to the Coastal Plain and primarily limited to coastal counties. Records are known as far inland as Hoke and Robeson Counties.

Some authors recognize three subspecies of Glossy Swampsnake; North Carolina populations can be assigned to the nominate L. r. rigida, the "Eastern Glossy Swampsnake". More complete molecular sampling is needed to determine if those subspecies correspond to discrete units.

Liodytes rigida was previously placed in the genus "Regina" for many years. McVay and Carstens (2013) revised the Thamnophiini tribe in part by resurrecting Liodytes based on molecular phylogenetic support and taxonomic priority.

The generic epithet Liodytes is derived from the Greek leios, "smooth", and dytes, "diver". The specific epithet rigida is from the Latin rigidus, apparently in reference to the stiff movements of these snakes.

Taxonomic References: Ernst et al. (2002); McVay and Carstens (2013).
Identification
Description: Glossy Swampsnakes are small to medium-sized aquatic snakes. Their dorsum is glossy brown to dark olive brown, with two faint dorsal strips typically visible. There are also jagged dark stripes along the lower portion of the first scale row. The venter is yellow to light green, with two rows of black to brown triangular to half-moon spots that converge to one row near the head. The labial scales and chin are typically pale orange or brown.
Morphological Features: Glossy Swampsnakes have 19 keeled midbody scale rows, reducing to 17 posteriorly. Ventral counts range from 124-144 (131-142 in NC specimens; Palmer and Braswell, 1995), with 50-71 (51-64) subcaudals and a divided anal plate. Head scale counts are typically as follows: 7 supralabials, 10 infralabials, 1 large loreal, 2 nasals, 2 preoculars, 2 postoculars, and 1+2 temporals. Palmer and Braswell (1995) noted some variation in scalation across multiple specimens in NC.

Glossy Swampsnakes have a maximum recorded total length of 79.7 cm (31.3 inches). Palmer and Braswell (1995) reported a 77.6 cm female specimen from NC. Tail lengths account for approximately 18-24% of total length. Females reach larger sizes than males; males have longer tails, more subcaudals, and fewer ventrals.

Glossy Swampsnakes have stout, chisel-like teeth useful for capturing their primary food source: crayfish. If threatened, they tend to flee towards water. They rarely bite when handled, instead expelling musk and flattening their heads. They are harmless to humans and pets.
Technical Reference: Palmer and Braswell (1995); Ernst and Ernst (2003).
Field Guide Descriptions: Palmer and Braswell (1995); Ernst and Ernst (2003); Beane et al. (2010).
Online Photos:    Google   iNaturalist   GBIF
Observation Methods: Glossy Swampsnakes are secretive and difficult to sample. Aquatic sampling with minnow traps or trashcan traps (Luhring and Jennison, 2008) may be effective. They also may be occasionally encountered on roads at night during and after rain.
Distribution in North Carolina
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: Glossy Swampsnakes are found in a variety of permanently flooded, still or sluggisly flowing waters in the Coastal Plain. These include sphagnum-choked streams, ponds, bays, swamps, and canals (Palmer and Braswell, 1995; Beane et al., 2010).
Biotic Relationships: Glossy Swampsnakes are primarily crayfish specialists, and are often referred to by the common name “Glossy Crayfish Snake” as a result. Unlike our other native crayfish-specialist snake—the Queensnake, Regina septemvittata, which primarily consumes crayfish that are actively molting or have recently undergone ecdysis—Glossy Swampsnakes will take both hard-shelled and molting prey, and it is suggested that their stout, chisel-like teeth are an adaptation for feeding on hard-shelled prey (Rossman, 1963). Other reported prey items include anurans (narrowmouth toads, cricket frogs, and true frogs) and fish, as well as one record of a siren or amphiuma. Juvenile Glossy Swampsnakes are reported to prey on dragonfly nymphs, aquatic beetle larvae, and other insect larvae (Hamilton and Pollack, 1956; Kofron, 1978; Palmer and Braswell, 1995; Ernst and Ernst, 2003; Gibbons and Dorcas, 2004; Durso et al., 2013).

The few reported predators of Glossy Swampsnakes include two-toed amphiumas, bullfrogs, and ophiophagous snakes (kingsnakes and cottonmouths), though it is often suggested that wading and predatory birds, alligators, turtles, carnivorous mammals, and various other ophiophagous snakes likely predate this species (Enge, 1998; Ernst and Ernst, 2003; Gibbons and Dorcas, 2004).
Life History and Autecology
Breeding and Courtship: Detailed reproductive data are lacking for Glossy Swampsnakes. Minimum size for maturity has been reported as 36 cm. Mating likely occurs in the spring (April to May).
Reproductive Mode: Glossy Swampsnakes are viviparous; young are typically born in late summer (August to September). Litters average 10 neonates; litter size is correlated with body size (Ernst and Ernst, 2003).

Neonates are approximately 18 cm in total length.
Aquatic Life History: Glossy Swampsnakes are primarily aquatic, and inhabit swamps, pocosins, and canals in low pine flatwoods. They may be salt tolerant and have been found in tidal waters.
Terrestrial Life History: Although considered primarily nocturnal, Glossy Swampsnakes will occasionally bask on branches overhanging water or on nearby banks, and can be found crossing roads after rain. They will also burrow in mud or under cover objects. They have been recorded in North Carolina from March–December; most records are from July to September.

Much remains to be learned about the natural history of this species. Home range estimates have not been reported.
General Ecology
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S2
Global Rank: G5
Status in North Carolina: SR

Photo Gallery for Liodytes rigida - Glossy Swampsnake

4 photos are shown.

Recorded by: Erich Hofmann and Kayla Weinfurther
Craven Co.
Comment: 		Recorded by: Erich Hofmann and Kayla Weinfurther
Craven Co.
Comment:
Recorded by: C. Helms, Hana Leonard
New Hanover Co.
Comment: 		Recorded by: C. Helms, Hana Leonard
New Hanover Co.
Comment: