Farancia abacura (Holbrook, 1836)
Key Characters: Red and black bars on belly; hard, spurlike tail tip; back scales smooth and shiny; anal plate divided.
Similar Species: No other Illinois snake has a glossy black back and red on the sides and belly. See the Key to Illinois Snakes for help with identification.
Subspecies: Two subspecies are currently recognized, Western Mudsnake, F. a. reinwardtii Schlegel, 1837, and Eastern Mudsnake, F. a. abacura. Only the former occurs in Illinois.
Description: Large (up to 150 cm TL) glossy black snake with alternating red and black bars on lower sides and belly, and small eyes. Male has a more bulbous tail and an area of smaller, keeled scales on the back above the vent.
Habitat: Shallow ponds, sloughs, and swamps containing rotting logs in the Coastal Plain of extreme southern counties. Often crosses roads on rainy nights.
Natural History: Mating takes place in midsummer and eggs are laid a few weeks later. Clutches of 4-104 eggs hatch in August or September. Hatchlings 18-24 cm TL resemble adults in coloration. Diet of this nocturnal snake consists entirely of amphibians: salamanders and their larvae, tadpoles, and frogs. Large wading birds and medium-sized mammals are the main predators, especially of the young. This snake has the startling defensive behavior of pushing its hard tail tip against the hand of someone holding it. This apparently is the “hoop snake” of folklore.
Status: Listed as a Species in Greatest Need of Conservation in the Illinois Wildlife Action Plan. Seldom seen even where populations are thought to be secure.
Etymology: Farancia – (New Latin) coined name; abacura – abacus (Latin) meaning board, ‘counting-board; reinwardtii – a patronym for Caspar Georg Carl Reinwardt (1773-1854).
Original Description: For abacura, Holbrook, J.E. 1836. North American Herpetology. J. Dobson and Son, Philadelphia; for reinwardtii, Schlegel, H. 1837. Essai sur la physionomie des serpens. Partie Générale: xxviii +251 S. + Partie Descriptive: 606 S. + xvi. La Haye (J. Kips, J. HZ. et W. P. van Stockum).
Type Specimen: For abacura, Holotype, ANSP 5164; for reinwardtii, lectotype designated as MNHN 3399
Type Locality: For abacura, “South Carolina”, restricted to Charleston, South Carolina by Schmidt (1953); for reinwardtii, “Louisiana”, restricted to vicinity of New Orleans by Schmidt (1953).
Original Name: For abacura, Coluber abacurus Holbrook, 1836; for reinwardtii, Homalopsis Reinwardtii
Nomenclatural History: Was briefly transferred to the genus Hydrops, a name used by S. Garman. Also moved to several other genera, including Calopisma and Helicops. Junior synonyms include Farancia Drummondii Gray, 1842 and Farancia fasciata Gray, 1849.