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Timber Rattlesnake

Scientific Name: Crotalus horridus

New York Status: Threatened
Federal Status: Not Listed


A dark-phase timber rattlesnake.The color of the
head determines whether it is dark or light phase.
Photo by William Hoffman.

Measuring from 3 to 4 feet or more in length, the timber rattlesnake is the largest venomous snake in New York. The record length in New York is 60 inches. Despite their size, cryptic patterns and coloration allow them to easily conceal themselves by blending in with their surroundings.

The coloration of the species is incredibly variable but can be broken down into two distinct color phases, light and dark. This designation is determined by the color of the head.

This species has coloration that varies considerably between individuals and populations. Dark crossbands or chevrons overlay the base color and can range from yellows and shades of brown to black. Timber rattlesnakes also have a dorsal strip, which is often chestnut but can vary between tan, light orange, and yellow. In dark individuals, this is often broken up by the chevrons. Snakes will have the same pattern and coloration for the duration of their lives. The pattern generally fades into black towards the tail, which results in the antiquated name "old velvet tail".

A member of the pit-viper family, the timber rattlesnake has paired temperature-sensitive openings, or loreal pits situated below and in between the eye and nostril. The purpose of this sensory organ is to detect prey and potential predators. Timber rattlesnake have a broad, triangular head with many small scales on the crown, bordered by a few large scales over the eyes, the loreal pit and rostrum (nose). Scales have a center ridge or keel, giving this rattlesnake a somewhat rough-skinned appearance.

The key feature distinctive to rattlesnakes-providing their namesake-is the rattle, which is made of loosely attached segments made of keratin. A new segment is added to the base of the rattle each time the snake sheds. When vibrated, the segments make rapid contact with each other, resulting in the buzzing sound characteristic of a disturbed rattlesnake.

Life History

A light-phase timber rattlesnake.
Photo by William Hoffman.

Timber rattlesnake have an active season that runs from late April until mid-October. In Northern New York, emergence is often delayed until mid-May. Upon emerging from the den, they are rather lethargic and spend most of their time under cover or basking under partly cloudy to sunny skies.

The species is considered migratory, meaning they originate from a central location and move out across the landscape. Gravid (pregnant) females migrate to gestating habitat- open, rocky ledges where temperatures are higher for embryo development. Overall, they generally migrate from 1.3 to 2.5 miles from their den each summer. Males move the greatest distances through their active season-up to 5 miles.

Mating season begins in the early summer and continues into early autumn. Males are especially active during this time and can be found using basking and gestating habitat and looking for receptive females. After mating, females store sperm through the winter until implantation of the embryos occurs during the following spring as temperatures increase.

Timber rattlesnakes are viviparous, meaning they give birth to live young. Following a gestation period of 4-5 months, females give birth to 4-14 (average 9) young every three to five years between late August to mid-September. Neonates (newborn) timber rattlesnakes are about 10-14 inches long at birth. Each neonate is born encased in a transparent membrane, or yolk sac, which is shed within a few minutes.

The young are miniature versions of adults, complete with hollow fangs, venom and a tiny rattle segment called a "pre-button". Shortly after birth, they shed their skin and drop their pre-button to reveal the button, or tip of a rattlesnake's rattle. They remain in the area with their mother for 1-2 weeks until they shed and disperse. In the fall the young follow their parent's scent trail back to the den for the winter.

Timber rattlesnakes are long-lived and reproduce at a low rate, making for slow population growth. Males may become sexually mature in as few as 5 years, whereas females take longer to reach sexual maturity, between 5 and 11 years. Juvenile mortality is very high, but once they reach maturity, the average life span may be between 15 and 20 years, with individuals being documented to have lived for more than 50 years in the wild.

Timber rattlesnakes shed their skin once and sometimes twice a year depending on the age of the animal and latitude of the population. A new segment is added to the base of the rattle each time shedding occurs. Snakes with a complete rattle are rarely seen-segments regularly break off during the year.

Rattlesnakes primarily fed on:

  • squirrels
  • chipmunks
  • voles
  • mice
  • small birds
  • amphibians

The venom, which is used primarily to immobilize prey, can be fatal to humans if the bite is untreated. However, in New York there have been no records of human deaths attributed to rattlesnakes in the wild during the last several decades. Less than 15% of the snake bites reported over a ten-year period were actually from a venomous snake. Contrary to popular opinion, a rattlesnake will not pursue or attack a person unless threatened or provoked. Such instances are likely a result of the observer being between the snake and it's point of cover. See if you encounter a timber rattlesnake below.

Distribution and Habitat

Map of Timber Rattlesnake distribution

The range of the timber rattlesnake extends from southern New Hampshire south through the Appalachian Mountains to northern Florida and west to southeastern Texas and southeastern Nebraska and Wisconsin. Populations are isolated in the Northeast. Historically, the species likely occurred in most mountainous and hilly areas of NYS, except in the higher elevations of the Adirondacks, Catskills, and Tug Hill region. They are now found in smaller numbers throughout the state with isolated populations in southeastern New York, the Southern Tier, and in the edges of the eastern Catskills and Adirondacks.

Timber rattlesnakes are generally found in deciduous hardwood forests in rugged terrain. They can also be found in lowlands, wetlands, or residential areas near dens. Crevices in rocky faces or talus with westerly to easterly southern exposures are used for denning or overwintering. Open areas with rocky surfaces are used for basking, shedding, and birthing. The surrounding forests provide foraging habitat.


While abundant in some areas, the timber rattlesnake population has severely declined in numbers and distribution (about 50-75%) in New York State due to unregulated collection, indiscriminate killing, and habitat destruction. Until outlawed in 1971, there was a bounty in certain counties in Northern New York for the rattles of these snakes. Even in areas without bounties, the rattlesnake was severely persecuted by local residents. In 1983, timber rattlesnakes were designated as a threatened species.

Despite these conservation efforts, their slow population growth is further hindered by:

  • development
  • road mortality
  • illegal collecting
  • continual disturbance of habitat by recreational users

Collecting timber rattlesnakes from the wild is now prohibited by law under Environmental Conservation Law 11-0535 and 11-0103(2)(c). However, poachers are still actively supplying the black market pet trade.

Management and Research Needs

The DEC coordinates survey efforts for many of the remaining populations in New York State. These are designed to:

  • verify the current status of known den sites;
  • develop baseline estimates of population size;
  • determine reproductive success; and
  • document any threats to existing habitat.

New denning locations are currently being discovered in areas where the density of overwintering sites is high. Protection and management of habitat is now a primary concern.

Additional survey work is necessary to verify status in many populations. Long-term comparative measurements of rattlesnake populations has only been conducted in a single population in NYS. The recent discovery of Snake Fungal Disease (leaves DEC website) has been noted in several populations of rattlesnake in New York. Further research is necessary to determine the full extent of the impacts of such infections. The impact may be determined by comparing populations of infected versus non-infected snakes.

If you encounter a timber rattlesnake:

Do not panic! Keep a safe distance of 6ft or more away. Let them move along on their own. Do not kill or collect the individual. Timber rattlesnakes are not aggressive unless provoked.

If an accidental bite occurs, seek medical attention immediately or call 911. To report sighting, or ask questions, contact your Regional Wildlife Office.

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