Western Ratsnake (Black Ratsnake complex)
Pantherophis obsoletus • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Colubrinae, Genus: Pantherophis, Species: P. obsoletus
Central and eastern United States, ranging from the Mississippi River west to the Great Plains, and from the Gulf of Mexico north into the southern regions of Canada.
Look up Western Ratsnake (Black Ratsnake complex) in the Snake Encyclopedia →Venomous Status
Non-venomous (Aglyphous)
Danger Level
Harmless. These snakes are non-aggressive towards humans, though they may bite if handled or cornered. Bites result in minor mechanical injury only.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Colubrinae, Genus: Pantherophis, Species: P. obsoletus
Conservation
IUCN status: Least Concern. Generally common and widespread, though threatened by habitat fragmentation and persecution by humans.
Physical Description
Based on the shed skin: weakly keeled scales are visible. Adults usually have a dark black or blotched dorsal pattern with a lighter, often checkered underside. The shed appears translucent but retains the texture of the dorsal scales.
Size & Dimensions
The shed skin appears to be approximately 4-5 feet in length. Adult Western Ratsnakes typically range from 3 to 6 feet, with record lengths reaching nearly 8 feet.
Habitat
Found in diverse environments including hardwood forests, wooded canyons, swamps, rocky hillsides, and frequently near agricultural buildings or residential areas. They are highly semi-arboreal.
Behavior & Temperament
Primarily diurnal or crepuscular, though they can be nocturnal in hot weather. They are excellent climbers. When threatened, they may 'kink' their body, vibrate their tail to mimic a rattlesnake, or release a foul-smelling musk.
Diet & Feeding
Active foragers that feed primarily on rodents, birds, and eggs. They utilize powerful constriction to dispatch their prey. They are often nicknamed 'Pilot Snakes' or 'Chicken Snakes' due to their presence near barns.
Reproduction
Oviparous (egg-laying). Females typically lay 10 to 20 eggs in mid-summer, often in hollow logs or leaf litter; eggs hatch in late summer or early fall.
Venom Profile
Non-venomous - no medically significant venom.
Look-alikes
Often confused with the North American Racer (Coluber constrictor), which has smooth scales, or various species of King Snakes and even Rattlesnakes due to tail-vibrating behavior.
Conservation Status
IUCN status: Least Concern. Generally common and widespread, though threatened by habitat fragmentation and persecution by humans.
Cultural Significance
Valued by farmers and homeowners as a highly effective form of natural pest control due to their preference for consuming destructive rodents.
Notable Features
The shed skin shows faint keeling on the dorsal scales (a ridge down the center of each scale). Ratsnakes are famous for their ability to climb vertical tree trunks using their specialized ventral scales.