Timber Rattlesnake
Crotalus horridus • Order: Squamata; Suborder: Serpentes; Family: Viperidae; Subfamily: Crotalinae; Genus: Crotalus; Species: C. horridus
Eastern United States from southern New Hampshire to north Florida, and west to southeastern Nebraska and central Texas. Significant populations in the Appalachians and upper Mississippi River valley.
Look up Timber Rattlesnake in the Snake Encyclopedia →Venomous Status
Venomous (Solenoglyphous - large, retractable front fangs)
Danger Level
Extremely Dangerous; it is one of North America's most dangerous snakes due to high venom yield, large size, and potent venom chemistry, though it is generally shy and non-aggressive.
Family
Order: Squamata; Suborder: Serpentes; Family: Viperidae; Subfamily: Crotalinae; Genus: Crotalus; Species: C. horridus
Conservation
IUCN Least Concern (declining); state-listed as Endangered or Threatened in many northeastern states due to habitat fragmentation and intentional killing.
Physical Description
Heavy-bodied pit viper with a large triangular head and elliptical pupils. Ground color is gray to tan with a series of dark brown to black V-shaped crossbands or chevrons. A distinctive black tail and a keratinous rattle are present. Scales are heavily keeled.
Size & Dimensions
Typical adult length 36 to 60 inches (91-152 cm); maximum recorded 74.5 inches. This specimen appears to be a mature adult based on the number of rattle segments.
Habitat
Upland forests with rocky outcrops or talus slopes for denning, as well as lowland cane brakes and bottomland hardwood forests. Elevation ranges from sea level to 2000 meters.
Behavior & Temperament
Secretive and docile compared to other rattlesnakes. Often relies on camouflage but will rattle loudly if threatened. Diurnal in spring/fall; nocturnal in hot summer months.
Diet & Feeding
Specializes in small mammals (squirrels, chipmunks, mice) and occasional birds. Uses heat-sensing pits to locate prey and employs an ambush (sit-and-wait) strategy near fallen logs.
Reproduction
Viviparous (gives birth to live young); females breed every 2 to 6 years depending on latitude. Litter size ranges from 5 to 14 young, typically born in late summer or early fall.
Venom Profile
Highly complex. While primarily hemotoxic (causing tissue necrosis and coagulopathy), some populations (Type A or B) possess neurotoxic components (canebrake toxin).
Look-alikes
Often confused with the Eastern Diamondback (Crotalus adamanteus), which has diamonds rather than chevrons, or the Copperhead (Agkistrodon contortrix), which lacks a rattle and has hourglass patterns.
Conservation Status
IUCN Least Concern (declining); state-listed as Endangered or Threatened in many northeastern states due to habitat fragmentation and intentional killing.
Cultural Significance
Historically served as an early American symbol (Gadsden flag 'Don't Tread on Me'). Plays a critical role in controlling rodent populations and tick-borne diseases.
Notable Features
Features a highly sophisticated infrared-sensing 'pit' between the eye and nostril and a rattle composed of interlocking segments of keratin added with each shed.