Crotalus horridus, the timber rattlesnake, is a species of venomous pitviper found in the eastern United States. This is the only rattlesnake species in most of the populous northeastern United States. No subspecies are currently recognized.
Adults usually grow to an average length of 91–152 cm (35.8-59.8 in). The maximum reported length is 189.2 cm (74.5 in).
Found in the eastern United States from southern Minnesota and southern New Hampshire, south to east Texas and north Florida. The type locality given is "America", although Schmidt (1953) proposed that this be restricted to "vicinity of New York City" (USA).
Generally, this species is found in deciduous forests in rugged terrain. During the summer, gravid (pregnant) females seem to prefer open, rocky ledges where the temperatures are higher, while males and non-gravid females tend to spend more time in cooler, denser woodland with a more closed forest canopy.
During the winter, Timber Rattlesnakes hibernate in dens, in limestone crevices, often together with Copperheads and Black Rat Snakes.
Their prey is mainly small mammals, but may include small birds, frogs, or other snakes. Although capable of consuming other rattlesnakes, the most common snakes they eat are garter snakes.
Potentially, this is one of North America's most dangerous snakes, due to its long fangs, impressive size and high venom yield. This is to some degree offset by its relatively mild disposition. Before striking, they often do a good deal of preliminary rattling and feinting.