Montana Field Guide

The gopher or bull snake can reach a length of 7 feet (it is Montana's largest snake), but most range from 3 to 5 feet. It can be readily identified by a series of large black to brown blotches that run down the back, and another series along the sides. The blotches, which are set on a yellow background, become more widely spaced toward the tail. The dorsal scales are keeled (have a ridge running down the center). A black band can usually be seen on the head in front of and extending below the eyes. The belly is yellow to white, often spotted with black (FWP). Dorsal coloration varies geographically, but in most areas has numerous dark blotches on a cream or yellowish background; 4 prefrontal scales; dorsal scales keeled; anal undivided; adults usually 90-183 cm in total length (Conant and Collins 1992, Stebbins 1985).

Differs from other similar species by having the following combination of characteristics: keeled scales, 4 prefrontals, and an undivided anal. rat snakes (elaphe) and kingsnakes (lampropeltis), have only two prefrontal scales. also, elaphe has a divided anal plate. whipsnakes (masticophis), racers (coluber), and indigo snakes (drymarchon) have smooth body scales.

Nonmigratory.

Gopher snakes are associated with dry habitats, including open pine forests. They feed on rodents, rabbits, ground-dwelling birds, and to a lesser extent lizards. They sometimes hiss and vibrate their tail when alarmed, producing a sound similar to that of rattlesnakes. They occasionally climb trees. Females lay 2 to 24 eggs in summer (FWP). N central MT: of 12 records, 9 in river valley, 1 in coulee, 2 on prairie (Mosimann and Rabb 1952). One found in rocky sagebrush area N of Arlee, MT (Franz 1971). Common in SE Alberta in brushy coulees, sage flats, & along roads (Lewin 1963).

Active forager by searching.

Overwinter survival in N UT > 88% (adults), 25% (juv.) (Parker and Brown 1980). Densities of 1.3 snakes/ha reported for ID (Nussbaum 1983).

Mate in late May-Jun; lay eggs late Jun-Jul; hatch late Aug- Sep (Hammerson 1982). Clutch size (P.C. SAYI) ave. 12.4 (Fitch 1970). Hatching success in N UT was 92% (Parker and Brown 1980).