Description: A moderate-length snake reaching a maximum total length of 1,194 mm (47.0 inches) (Conant and Collins, 1991). In Virginia, maximum known snout-vent length (SVL) is 1,031 mm (40.6 inches) and maximum total length is 1,188 mm (46.8 inches). In the present study, tail length/total length was 10.1-16.2% (ave. = 12.9 ± 1.4, n = 69).

Scutellation: Ventrals 193-212 (ave. = 200.9 ± 4.0, n = 70); subcaudals 37-53 (ave. = 44.5 ± 3.8, n = 66); ventrals + subcaudals 234-255 (ave. = 245.2 ± 5.1, n = 62); dorsal scales smooth, scale rows usually 21 (88.6%, n = 70) at midbody, but may be 22-23 (11.4%); anal plate single; infralabials 8/8 (57.6%, n = 59), 9/9 (30.5%), or other combinations of 6-9 (11.9%); supralabials 7/7 (89.2%, n = 65) or 7/8 (10.8%); loreal scale present; preoculars 1/1; postoculars 2/2; temporal scales usually 2+3/2+3 (77.8%, n = 63) or other combinations of 1-4 (22.2%).

Coloration and Pattern: Dorsal color of body, head, and tail tan to dark brown, and a yellowish tinge may be present; dorsum with a series of 35- 54 (ave. = 44.3 ± 4.0, n = 61) chestnut-brown to tan blotches that are wider (about 11 scales) than long (1-2 scales); blotches well separated and narrowly bordered in black in juveniles and young adults; blotches bordered by brown in old adults, if at all; blotches fade with age and old individuals may be uniformly brown; some individuals possess a series of small, alternating, brown or tan blotches on each side; venter cream to yellowish with varying amounts of faded brown smudges; chin and labial scales peppered black in some snakes, and scales of head bordered by dark-brown pigment; short brown eye-jaw stripe may be present, which does not extend beyond upper margin of supralabials; yellow pigment fades to cream in preservative. This is a cylindrical snake with a small head that is not distinct from the neck.

Sexual Dimorphism: Sexual dimorphism is shown in body proportions and scutellation. Adult male SVL (660-1,031 mm, ave. = 840.6 ± 102.9, n = 31) averaged larger than adult female SVL (672-984 mm, ave. = 799.6 ± 97.4, n = 15), and males reached larger total lengths (to 1,188 mm) than females (to 1,101 mm). Sexual dimorphism index was -0.05. Females had a lower average tail length/total length (10.1-14.5%, ave. = 12.1 ± 1.3, n = 24) than males (10.7-16.2%, ave. = 13.4 ±1.2, n = 40). Subcaudal scale counts averaged higher in males (40-53, ave. = 46.6 ± 2.7, n =38) than in females (37-49, ave. = 41.4 ± 2.7, n = 23). Number of ventral scales (males 193-210, ave. = 200.4 ± 3.7, n = 41; females 193-212, ave. = 202.4 ± 4.1, n = 24) and number of ventrals + subcaudals (males 238-255, ave. = 246.8 ± 4.6, n = 36; females 234-253, ave. = 243.6 ± 4.9, n = 21) were not sexually dimorphic.

Juveniles: Juveniles and hatchlings possess a series of chestnut brown dorsal blotches that are bordered by black. Each has a dark-brown checkerboard pattern on the cream to yellow venter, a short reddish eye-jaw stripe that does not pass beyond the upper margin of the supralabial scale, and 2 longitudinal chestnut to brown stripes on the back of the head. These patterns fade with age. Hatchling SVL in Virginia was 176-210 mm, total length was 200-236 mm, and mass was 2.7- 6.5 g (Hedges, 1976a; Ernst et al., 1985).

Confusing Species: This snake may be confused with Pantherophis guttatus and Lampropeltis triangulum, especially with the Piedmont and montane forms of the latter. Adults of these two species have larger, distinctly black-bordered, and fewer dorsal body blotches, and exhibit distinct ventral black-and-white-checkerboard patterns. Juveniles of these species are patterned as adults and possess eye-jaw stripes that pass to or beyond the margin of the mouth. Mole kingsnakes are sometimes misidentified as Eastern Copperheads (Agkistrodon contortrix). However, Eastern Copperheads have brown hourglass crossbands and heads that are distinctly wider than the neck.

Geographic Variation: Average number of ventral + subcaudal scales varied from low counts in the northern Blue Ridge Mountains (239.0 ± 5.0, 234-244, n = 3) to intermediate counts in the upper Piedmont (245.5 ± 4.8, 234-254, n = 40) to high counts in the lower Piedmont (248.2 ± 4.3, 243-255, n = 10). This character in the lower and upper Coastal Plain averaged 242.6 ± 4.5 (238-253, n = 9). Other scale characters showed no apparent geographic variation. The average numbers of body blotches in the upper Piedmont (44.3 ± 3.8, 35-54, n = 38) and upper Coastal Plain (45.3 ± 2.8, 41-48, n = 7) were intermediate between those in the northern Blue Ridge Mountains (40.8 ± 2.6, 37-43, n = 4) and the southern Coastal Plain (50.0, 49-51, n = 2).

Biology: Mole kingsnakes are subterranean snakes found in agricultural fields, abandoned fields undergoing succession, pine woods, and mixed pine-hardwood forests. They are sometimes found in woodlots and fields in urban areas and are occasionally turned up by the plow. The habitat is usually more xeric than mesic. They occasionally occur above ground during the day or night crossing roads, usually after rains. Few have been found under surface objects. They apparently burrow into sandy and loamy soils themselves but probably use rodent burrows and rotting tree root passageways when available. Clifford (1976) found this species to be active May-September in Amelia County. Museum record extremes are 5 April and 29 October.

Mole kingsnakes are predators of small mammals, birds, and lizards. Unidentified rodent hair was found in 4 of 33 specimens I examined for stomach contents. De Rageot (1964) listed skinks (Plestiodon spp.), Eastern Fence Lizards (Sceloporus undulatus), Northern Rough Greensnake (Opheodrys aestivus), and mice as prey of a captive from Surry County. Species eaten by this snake in Kansas (Fitch, 1978) that may be prey of Virginia L. c. rhombomaculata include Six-lined Racerunners (Aspidoscelis sexlineata), Five-lined Skinks (P. fasciatus), Slender Glass Lizards (Ophisaurus attenuatus), Ring-Necked Snakes (Diadophis punctatus), Black Racers (Coluber constrictor), juvenile Timber Rattlesnakes (Crotalus horridus), eastern moles (Scalopus aquaticus), northern short-tailed shrews (Blarina brevicauda), whitefooted mice (Peromyscus leucopus), juvenile eastern cottontails (Sylvilagus floridanus), hispid cotton rats (Sigmodon hispidus), house mice (Mus musculus), and voles (Microtus spp.). Other prey types recorded for this species are hylid frogs, ranid frogs, and grasshoppers (Ernst and Barbour, 1989b). Each prey is killed by constriction. Predators of Northern Mole Kingsnake are Eastern Kingsnakes (Lampropeltis getula), owls, hawks (Buteo spp.), opossums (Didelphis virginiana), skunks (Mephitis, Spilogale), raccoons (Procyon lotor), and foxes (Urocyon, Vulpes) (Ernst and Barbour, 1989b).

Little is known about reproduction in this species in Virginia. Mating probably takes place in spring and perhaps fall, although no records have been recorded in the literature. Mating behavior is described in Ernst and Barbour (1989b). Clutch size in Virginia was 7-18 (ave. = 13.5 ± 4.8, n = 4); it was 7-21 from throughout its range (Ernst and Barbour, 1989b). Known egg-laying dates in Virginia are 16-17 June and 5 July. Eggs from one clutch of 15 eggs averaged 27.8 x 21.1 mm (length 25.3-33.3, width 17.4-23.2) (Ernst et al., 1985) and from another of 13 averaged 31 x 20 mm (length 28-34, width 19-20) (Hedges, 1976a). Laboratory incubation time was 62-78 days and hatchlings emerged 15-16 August and 19-21 September.

The population ecology of this snake has been studied only in Kansas (Fitch, 1978). A total of 166 Mole Kingsnakes were found in a 30-year study, yielding an estimated density of 0.55 per hectare. Clifford (1976) recorded 10 Northern Mole Kingsnake out of a total of 278 in a 4-year period in Amelia County. The rarity of this snake is due to its secretive behavior; it may be more abundant than we are aware.

Remarks: Other common names for this species in Virginia are brown snake (Hay, 1902); house snake, ground snake, and molecatcher (Dunn, 1915a, 1918); mole snake (Carroll, 1950; Burger, 1958; Conant, 1975); and brown kingsnake and blotched kingsnake (Linzey and Clifford, 1981).

Because so little of the biology of this species is known in Virginia, any information on its natural history and behavior should be reported.

Conservation and Management: The fact that this species is widely distributed and occurs in agricultural areas indicates it is not threatened with extirpation in its Virginia range. However, loss of habitat in northern Virginia in general and in the urban crescent (the Washington-Richmond-Norfolk corridor) in particular causes some alarm. Maintaining a mosaic of hardwood corridors and open grassy areas will ensure this species is retained in the local fauna.

U.S. Range