Western Rat Snake
Pantherophis obsoletus • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Colubrinae, Genus: Pantherophis, Species: P. obsoletus
North America. Found throughout much of the central United States, from the Mississippi River west to the Rocky Mountains and north to Minnesota and south to the Gulf of Mexico (Texas, Louisiana, Oklahoma, Arkansas, Kansas, Missouri, Nebraska, Iowa).
Look up Western Rat Snake in the Snake Encyclopedia →Venomous Status
Non-venomous (Aglyphous - lacking specialized fangs).
Danger Level
Harmless. They are non-aggressive, though they may bite in self-defense if handled or cornered. Bites result in minor scratches but pose no toxic threat.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Colubrinae, Genus: Pantherophis, Species: P. obsoletus
Conservation
IUCN Status: Least Concern. Populations are stable, though they face threats from habitat fragmentation and intentional killing by humans due to fear and confusion with venomous species.
Physical Description
Large, powerful body with weekly keeled scales. Adults are often solid black (especially in the north) or greyish with darker splotches. This specimen shows a light ventral (belly) coloration with dark checkering and a cream-colored body with dark blotches typical of central/southern populations. Eyes have round pupils.
Size & Dimensions
Typically 106–183 cm (3.5–6 ft) in length. Maximum recorded is 256.5 cm (8.4 ft). The specimen in the image appears to be a healthy sub-adult or adult based on girth relative to the window frame.
Habitat
Generalist. Prefers hardwood forests, timbered canyons, and rocky hillsides, but frequently found in agricultural areas, prairies, and suburban environments. Known for climbing trees and structures; elevation ranges from sea level to approximately 1,300 meters.
Behavior & Temperament
An exceptional climber (as seen in the photo). Primarily diurnal but becomes nocturnal during hot summer months. When threatened, they often 'kink' their body to disrupt their outline or vibrate their tail in dry leaves to mimic a rattlesnake. Generally docile but can be defensive if restricted.
Diet & Feeding
Active forager and powerful constrictor. Specializes in rodents, birds, and bird eggs. Their ability to climb allows them to raid bird nests and enter attics or barns in search of mice.
Reproduction
Oviparous (lays eggs). Females lay 10–30 eggs in early summer, often in rotting logs, mulch piles, or hollow trees. Hatchlings emerge in late summer or early autumn.
Venom Profile
Non-venomous - no medically significant venom.
Look-alikes
North American Racers (Coluber constrictor) are faster and have smooth scales. Bullsnakes (Pituophis catenifer) have a more pointed snout and heavier keeling. As juveniles, they are often confused with Copperheads (Agkistrodon contortrix) due to their blotched pattern, but lack the heat pits and triangular head of vipers.
Conservation Status
IUCN Status: Least Concern. Populations are stable, though they face threats from habitat fragmentation and intentional killing by humans due to fear and confusion with venomous species.
Cultural Significance
Highly valued by farmers and homeowners for ecological pest control, as they can consume large numbers of agricultural pests like rats and mice. Often subject to folklore regarding their climbing abilities.
Notable Features
Remarkable climbing ability; it is colloquially said that 'if a snake is in a place where a snake shouldn't logically be, it is a rat snake.' They utilize the edges of their ventral scales to grip microscopic imperfections in vertical surfaces, as demonstrated by the specimen climbing the window mullions in the image.