Pituophis catenifer

Dorsum yellowish or cream with numerous dark blotches; usually a dark stripe across the head between the eyes and from each eye to the angle of the jaw; belly usually cream or yellowish with dark spots; dorsal scales keeled; anal scale single; usually four prefrontal scales; vertical keel at opening of windpipe; maximum total length around 280 cm but rarely more than 180 cm.

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.

This species occurs in a wide range of habitats, extending from lowlands to mountains: desert, prairie, shrubland, woodland, open coniferous forest, farmland, and marshes. Midwestern populations inhabit prairies; western and Mexican populations range from coastal grasslands and forests through deserts into montane forests (Sweet and Parker 1990). This snake is terrestrial, fossorial, and arboreal. It remains underground in cold weather and during the hot midday period in summer; it may occupy mammal burrows (Schroder 1950, Fitch 1958) or dig its own burrow, aided by the pointed snout and enlarged rostral scale. Carpenter (1982) estimated that burrowing Pituophis could move up to 3,400 cubic cm of soil in an hour. Eggs are deposited in burrows excavated by females in loose soil, in spaces beneath large rocks or logs, or possibly in small mammal burrows.

Population density was estimated at 0.3-1.3/ha in Utah and Idaho (Parker and Brown 1980, Nussbaum 1983).

This snake is remarkably variable in its behavior. Some individuals lie motionless when approached, remaining passive even when handled. Others respond to approach by coiling and striking (often lunging forward and grunting with each strike), hissing loudly, and vibrating the tail. The jaws may be spread, giving the head the triangular shape typical of rattlesnakes. In dry vegetation the vibrating tail may produce a sound resembling that made by a rattlesnakes rattle. Some individuals produce a rattling hiss that closely resembles the sound of a rattlesnakes rattle. Source: Hammerson (1999).

The mating period extends from April to early June over much of the range (Ernst and Barbour 1989). Eggs are laid as early as June in some areas or as late as August in other regions (Ernst and Barbour 1989). Clutch size is 2-24. Generally individual females produce one clutch per year. Incubation typically takes 50-100 days, with 70-75 days most common (Parker and Brown 1980, Ernst and Barbour 1989). In many areas, hatchlings emerge in August and September. In Utah, males reach sexually maturity in 1-2 years, females in 3-5 years (Parker and Brown 1980). Females appear to have an annual breeding cycle (Fitch 1970, Diller and Wallace 1996).