|Common Name:||Common Rainbow Snake|
|Scientific Name:||Farancia erytrogramma erytrogramma|
|Genus:||Farancia has no known meaning.|
|Species:||erytrogramma combines two Greek words, erythros which means red and gramma which means line or picture, referring to the dorsal red stripes.|
|Subspecies:||erytrogramma combines two Greek words, erythros which means red and gramma which means line or picture, referring to the dorsal red stripes.|
|Vernacular Names:||Horn snake, mud snake, red-lined snake, red-lined horned snake, red-sided snake, sand hog, sand snake, striped wampum.|
|Average Length:||27 - 48 in. (68.8 - 122 cm)|
|Virginia Record Length:|
|Record length:||66 in. (167.6 cm)|
PHYSICAL DESCRIPTION: This is a shiny iridescent snake with three red stripes on a bluish-black background. A broad reddish stripe bordered with black spots runs down the center of the belly and is flanked by yellow-orange coloration. The body is relatively stout and the head is barely distinct from the neck. The tail is short and ends in a spinelike tip. The juvenile is similar to the adult. The dorsal scales are smooth except above the anal region where they may be keeled. There are 19 scale rows and the anal plate is usually divided but is often single in Virginia. They are 8 inches or more at birth and they grow to between 36-44 inches with a maximum of 60 inches *1006*. In Virginia, maximum known SVL is 1518 mm (59.8 in.) and maximum total lenth is 1733 mm (68.2 in.).
COLORATION and PATTERN: iridescent with 3 red stripes on a black dorsum; middorsal stripe extends only to base of tail, whereas the lateral stripes on scale row 6 (counting from the ventrals on each side) extend onto dorsum of the tail; coloration below the 6th scale row is usually black; venter yellow with 2 primary rows of black spots - there may be a shorter, 3rd midventral row in some specimens; dorsum of head black to slate blue with some of the scales edged in red, forming an artistic pattern; throat, chin, infralabials, and supralabials yellow; each supralabial and some of the infralabials and chin shields have distinct black spots; yellow and red coloration fades to white in preservative. These are stout, cylindrical snakes with no difference in the width of the head and neck. The tail has a sharp spine.*10760*
SEXUAL DIMORPHISM: Sexual dimorphism is exhibited in size, pattern, and scutellation. Adult females reach longer snout vent lengths (781-1518 mm, avg. = 1051.1+/-220.9, n=16) than males (722-730 mm, avg. = 726, n=2). Sexual dimorphism index is 1.45. However, tail length/total length ratio in males is higher (17.0-17.4%, avg. = 17.2, n=2) than in females (10.5-15.8%, avg. = 12.3+/-1.3%, n=16). Females have a higher number of ventrals (avg. - 170.8+/-2.3, 167-175, n=31) than males (159.2+/-1.5, 157-161, n=6). Counts of ventrals + subcaudals for males (204-210 avg. = 208.8+/-3.0, n=28). The midventral spots are usually more distinct in males than in females.*10760* Richmond reported that hatchlings from New Kent Co. were sexually dimorphic in number of ventrals (females 170-175, avg. = 172.0+/-1.2, n=39;; males 155-162, avg. = 159.3+/-1.5, n=46) and number of subcaudals (females 35-42, avg. = 37.6+/-1.3; males 44-49, avg. = 46.5+/-1.0) and ventrals + subcaudals (females 207-215, avg. = 209.7+/-1.6; males 202-210, avg. = 205.8+/-1.8). The midventral row of black spots is more pronounced in male hatchlings than females. However, these are statistical differences and cannot be used to assign gender to single individuals. *10760*
JUVENILES: Juveniles are colored and patterned as adults. Hatchlings averaged 196.3+/-3.0 mm SVL (170-222, n=81), 231.3 +/-13.6 mm total length (197-270, n=81),and 5.9+/-1.1 g body mass (3.6-8.7, n=68).*10760* Confusing Species: No other Virginia snake is as multicolored as F. erytogramma. Mud snakes (F. abacura) have stout bodies and are shiny, but are uniformly black dorsally and red ventrally with some overlap on the sides.*10760*
GEOGRAPHIC VARIATION: There is no geographic variation in pattern, color, or scutellation in Va.*10760* Reproduction: This species lays up to 52 eggs in an underground cavity in sandy soil, usually during July. The leathery white eggs are deposited from to 18 inches below the surface in exposed, dry, sandy fields.*1006* Females remain with their eggs in the nest, presumably to confer some protection against predation.*10760* The young hatch in the fall and overwinter on land, probably in a burrow near the nest, and move overland to an aquatic area in early spring. The males may reach sexual maturity by the end of their second or the beginning of their third year. The female probably reach maturity by the end of the third year, possibly the second *1006*.
BEHAVIOR: These snakes are both aquatic and burrowers. They are exellent swimmers but usually prowl along stream or swamp bottoms. At times they burrow into muck or mud. They have been found in dry sand at depths of up to 10 feet. The young have been found beneath boards logs and other debris. They may use their sharp tiped tail to probe. They have no definite period of hibernation since active specimens have been reported during every month. The main food of this species is eels. After catching an eel the snake usually climbs out of the water where the prey is swallowed head first. They may often rest with the tail dangling from its mouth *1006*.
AQUATIC/TERRESTRIAL ASSOCIATIONS: This species is preyed on by aquatic turtles, raccoons, opossums, skunks, kingsnakes and hawks *1006*. Nothing is known of the population ecology of this species anywhere in its range. Richmond plowed up 20 rainbow snakes in a 10 ac. field on one day in New Kent Co. Rainbow snakes will not bite, but will thrash about vigorously when picked up and attempt to scratch or poke the handler with the spine on the tail (it will not pierce the skin). These snakes appear to be oblivious to humans unless picked up. *10760*
References for Life History
*Click on a thumbnail for a larger version.
|Adult King William Co.||Adult King William Co.||Adult King William Co.||Adult King William Co.||Adult King William Co.|