Rattlesnakes live in Pennsylvania, though their presence is limited to specific, remote, and undisturbed wilderness areas. The single species found across the state is a large pit viper. This article focuses on the characteristics and habitat of this snake, along with measures for safe coexistence.
The Timber Rattlesnake
The species inhabiting Pennsylvania is the Timber Rattlesnake (Crotalus horridus). These are large, heavy-bodied snakes, typically reaching lengths between 36 and 60 inches. Their coloration is highly variable, ranging from shades of yellow or gray to deep black, featuring dark brown or black chevron-shaped crossbands along the back.
The snake has a broad, triangular head distinctly separated from the neck, and a black tail terminating in a segmented rattle. The rattle grows a new segment each time the snake sheds its skin, which can happen multiple times a year; however, older segments often break off. Despite being venomous, the Timber Rattlesnake is mild-mannered and generally non-aggressive, preferring to remain coiled or retreat when encountered.
This species is long-lived, potentially reaching 30 years in the wild, but it is slow to reproduce. Females in northern populations, including Pennsylvania, may not reach sexual maturity until they are five to nine years old. They give birth to a small litter of three to 13 live young in late summer or early fall, and typically only reproduce every two to three years. This low reproductive rate makes the populations vulnerable to decline from human-caused mortality or habitat loss.
Geographic Range and Habitat
The Timber Rattlesnake is primarily associated with rugged, forested terrain throughout much of Pennsylvania. Populations are concentrated in the mountainous regions, particularly along the Appalachian ridges. They are generally absent from the heavily developed southeastern corners of the state and some areas along the western border.
The den site, known as a hibernaculum, is often located on south-facing rocky slopes or outcrops. These dens consist of deep rock crevices that extend below the frost line, allowing the snakes to survive the winter. Males and non-gravid females typically disperse from the den in late spring to forage in the cooler, denser deciduous forest for small mammals and birds.
Gravid (pregnant) females exhibit different movement patterns, often remaining in open, sun-exposed rocky areas near the den throughout the summer. This behavior is essential for thermoregulation, as the higher temperatures are necessary for the development of their young. They give birth in these open areas before returning to the communal den for the winter, often following the same routes each year.
Safe Encounters and Legal Protection
Encountering a Timber Rattlesnake in the wild is rare, but safe practices involve respecting the animal’s space and minimizing potential conflict. If a snake is sighted, the safest response is to maintain a significant distance and allow it to move away naturally without intervention. Never attempt to handle, harass, or provoke the snake, even if it appears to be dead, as most bites occur when people try to interact with them.
Hikers in known rattlesnake territory should wear sturdy, closed-toe footwear that covers the ankles and pay attention to where they step or place their hands. Areas like rocky ledges, fallen logs, and high grass should be approached with caution, as these spots offer ideal basking or ambush locations. If the characteristic rattling sound is heard nearby, calmly retreat from the area and proceed along a different route.
The Timber Rattlesnake holds a protected status in Pennsylvania, and it is illegal to kill, injure, or possess one without a permit from the Pennsylvania Fish and Boat Commission. Penalties may apply for illegally harming this species. In the unlikely event of a bite, the victim must seek immediate medical attention; attempts to apply a tourniquet or cut and suction the venom should be avoided.