New York Natural Heritage Program
Timber Rattlesnake
Crotalus horridus Linnaeus, 1758

Identifying Characteristics [-]
This is a heavy bodied snake of forested uplands. The young measure approximately 12 inches at birth and adults range from 36 to 60 inches in length (Conant and Collins 1998). The coloration and pattern is highly variable geographically (Conant and Collins 1991) with two main color variations, yellow or black, found in New York. The yellow variation has a yellow head and body with black or dark brown crossbands and the crossbands, which may be "V"-shaped, may break up anteriorly to form a row of dark spots down the back and along each side of the body (Conant and Collins 1998). The black variation has a black head and body with black crossbands and a reddish mid-dorsal stripe may be present. Some individuals that are considered to be the black variation have black heads, yellow bodies, and dark crossbands. In some locations, completely black specimens are not unusual (Conant and Collins 1998). The scales have longitudinal keels giving the snake a rough textured appearance. Timber rattlesnakes, like other pit-vipers, have a two heat-sensitive openings, or pits, situated below and between the eye and nostril. This sensory organ aids the snake in the detection of prey. As the name implies, rattlesnakes also have a rattle at the end of the tail that is made up of loosely attached segments. A new segment is added each time the snake sheds it skin, which is about 1.5 times per year. When disturbed, a rattlesnake will vibrate its tail, causing the loose segments to create a buzzing sound.

Characters Most Useful for Identification [-]
The presence of a rattle is the most useful diagnostic characteristic.

Best Life Stage for Proper Identification [-]
Adults may be easier to identify than newborn rattlesnakes, but in general the coloration and pattern of adults and young are similar, although newborn timber rattlesnakes may be more gray in color. Newborn timber rattlesnakes have a single rattle segment called a button.

Behavior [-]
In New York, timber rattlesnakes hibernate in communal dens, often with copperheads (also venomous), and other species non-venomous snakes. Depending on the latitude and local weather conditions, hibernation generally begins from mid-September through late-October and continues through the winter until late-March through mid-May. During the active season, rattlesnakes will generally use forested habitats up to 2.5 miles (4 km) or greater from their overwintering dens for foraging and other activities. Mating takes place during late-July to early-August and the young are born in August or September of the subsequent year.

Diet [-]
Timber rattlesnakes mainly prey upon small rodents such as mice, chipmunks, and gray squirrels, but they will also take songbirds on occasion.
Timber Rattlesnake Images
click to enlarge
The Best Time to See
In general, timber rattlesnakes are active from late April until mid-October. In some locations, rattlesnakes may start to enter dens in mid-September and may not emerge until late-May, especially at more northern locations.
Present Reproducing
The time of year you would expect to find Timber Rattlesnake present (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Massasauga (Sistrurus catenatus)
    In New York, the massasauga is found in wetland habitat in the central and western part of the state and the range of the two species do not overlap. Otherwise, the two can be differentiated by the scalation on the head; the massasauga has nine plates on the crown of its head instead of the numerous small scales found on the timber rattlesnake (Conant and Collins 1998).
  • Copperhead (Agkistrodon contortrix)
    The northern copperhead often occurs with the timber rattlesnake in southeastern New York. Copperheads can be distinguished from timber rattlesnakes by their coppery-orange head, hourglass shaped crossbands, and lack of a rattle.