Timber Rattlesnake

Crotalus horridus Linnaeus, 1758

Timber Rattlesnake (Yellow Phase)
Jesse W. Jaycox

Reptilia (Reptiles)
Viperidae (Vipers and Pit Vipers)
State Protection
Listed as Threatened by New York State: likely to become Endangered in the foreseeable future. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
Vulnerable in New York - Vulnerable to disappearing from New York due to rarity or other factors (but not currently imperiled); typically 21 to 80 populations or locations in New York, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines.
Global Conservation Status Rank
Apparently Secure globally - Uncommon in the world but not rare; usually widespread, but may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors.


Did you know?

Newborn Timber Rattlesnakes, often born well away from the overwintering den, follow the scent trails of adult snakes back to the den for hibernation (Brown and MacLean 1983, Reinert and Zappalorti 1988).

State Ranking Justification

There are approximately 205 extant dens known in the state, but when interacting and potentially interacting populations are taken into consideration, the number of occurrences will be in the range of 35 to 60. Indiscriminate killing and unregulated collecting, including a past bounty system in some portions of the range, has resulted in many populations becoming extirpated or depleted in numbers in most areas where the species was once numerous. Bounties on Timber Rattlesnakes were outlawed in New York State in 1971, but even in areas without bounties, rattlesnakes were collected or severely persecuted by local residents in many areas. These factors, combined with a low reproductive potential, and current threats such as development, illegal collecting, and other disturbance factors will likely prevent or slow population recovery.

Short-term Trends

Declines and extirpation of some Timber Rattlesnake populations have been documented within the past 25 years and will likely continue to some degree given current threats.

Long-term Trends

Timber Rattlesnakes have been subjected to substantial reduction due to specimen collection and persecution during the past century and it is believed that denning populations in New York have been reduced by 50% to 75% of their historical numbers (Brown 1984, 1988). Management efforts focused on habitat protection and public education have somewhat stabilized the remaining populations, but loss of habitat continues to be a threat to the species.

Conservation and Management


Loss of habitat, habitat fragmentation, mining, road mortality, illegal collecting, persecution, and pathogenic organisms are all considered threats to Timber Rattlesnake populations.

Conservation Strategies and Management Practices

Habitat fragmentation from development, logging, and illegal snake collecting and persecutions have impacted Timber Rattlesnake populations in New York. Fragmentation can be reduced by planning development that leaves contiguous undisturbed areas that includes dens, basking, gestating, and foraging areas. If contiguous habitat is not possible, then corridors would provide means for snakes to move between seasonally used habitats. Public education materials or public meetings in residential areas near rattlesnake habitat that informs residents of rattlesnake biology to help reduce misconceptions, fear, and accidental encounter advice. Nuisance response efforts aimed at moving rattlesnakes out of areas where they may be harmed are in effect in some areas and these efforts may be useful in other locations where homes are located within the summer foraging habitat. Logging should occur during the winter months when the snakes are hibernating. Some logging may be beneficial by opening basking and gestating habitats and remaining brush piles may provide cover and improved foraging opportunities (NatureServe 2019). There are still people that want to either illegally collect or harm rattlesnakes. Land managers should avoid disclosing known rattlesnake areas, especially dens, basking, and gestating areas. Recreational use trails should be routed to avoid these seasonally-used concentration areas. Some snakes may be sensitive to frequent visits by researchers (NatureServe 2019). Continuous disturbances may lead to abandonment. Studies should be carefully planned to minimize negative effects of site visits. Additionally, roads act as barriers by preventing snakes from moving freely in suitable habitat and reducing genetic exchange. Mortality increases as the volume of cars increase. Mortality can be decreased by reducing speed limits during active seasons, adding fencing that leads to culverts for safe passage under roads, and road closures when possible (Choquette and Valliant 2016). Vegetation thinning at den, basking, and gestating areas may be needed in areas that have become overgrown (NatureServe 2019).

Research Needs

Standardized survey protocols need to be developed and implemented at all known and potentially suitable sites to document the character, quality, and extent of occupied habitat. Additional research is needed to determine long-term effects of pathogens and ways to reduce irreversible population decline.



In the Northeast, this species inhabits mountainous or hilly deciduous or mixed deciduous-coniferous forests, often with rocky outcroppings, steep ledges, and rock slides (Petersen and Fritsch 1986, Brown 1993). Dens, or hibernacula, are located in rocky areas where underground crevices provide retreats for overwintering (Brown 1993). New York dens are often located in accumulations of talus below ledges or in fractures within or underneath ledges or rock outcrops. Rattlesnakes use open canopy, rocky areas for basking, shedding, gestating, and birthing. Foraging areas are generally located within forested habitat surrounding the den.

Associated Ecological Communities

  • Acidic talus slope woodland (guide)
    An open to closed canopy woodland that occurs on talus slopes (slopes of boulders and rocks, often at the base of cliffs) composed of non-calcareous rocks such as granite, quartzite, or schist.
  • Appalachian oak-hickory forest (guide)
    A hardwood forest that occurs on well-drained sites, usually on ridgetops, upper slopes, or south- and west-facing slopes. The soils are usually loams or sandy loams. This is a broadly defined forest community with several regional and edaphic variants. The dominant trees include red oak, white oak, and/or black oak. Mixed with the oaks, usually at lower densities, are pignut, shagbark, and/or sweet pignut hickory.
  • Appalachian oak-pine forest (guide)
    A mixed forest that occurs on sandy soils, sandy ravines in pine barrens, or on slopes with rocky soils that are well-drained. The canopy is dominated by a mixture of oaks and pines.
  • Beech-maple mesic forest (guide)
    A hardwood forest with sugar maple and American beech codominant. This is a broadly defined community type with several variants. These forests occur on moist, well-drained, usually acid soils. Common associates are yellow birch, white ash, hop hornbeam, and red maple.
  • Calcareous cliff community (guide)
    A community that occurs on vertical exposures of resistant, calcareous bedrock (such as limestone or dolomite) or consolidated material; these cliffs often include ledges and small areas of talus.
  • Calcareous talus slope woodland (guide)
    An open or closed canopy community that occurs on talus slopes composed of calcareous bedrock such as limestone or dolomite. The soils are usually moist and loamy; there may be numerous rock outcrops.
  • Chestnut oak forest (guide)
    A hardwood forest that occurs on well-drained sites in glaciated portions of the Appalachians, and on the coastal plain. This forest is similar to the Allegheny oak forest; it is distinguished by fewer canopy dominants and a less diverse shrublayer and groundlayer flora. Dominant trees are typically chestnut oak and red oak.
  • Cliff community (guide)
    A community that occurs on vertical exposures of resistant, non-calcareous bedrock (such as quartzite, sandstone, or schist) or consolidated material; these cliffs often include ledges and small areas of talus.
  • Floodplain forest (guide)
    A hardwood forest that occurs on mineral soils on low terraces of river floodplains and river deltas. These sites are characterized by their flood regime; low areas are annually flooded in spring, and high areas are flooded irregularly.
  • Hemlock-northern hardwood forest (guide)
    A mixed forest that typically occurs on middle to lower slopes of ravines, on cool, mid-elevation slopes, and on moist, well-drained sites at the margins of swamps. Eastern hemlock is present and is often the most abundant tree in the forest.
  • Limestone woodland (guide)
    A woodland that occurs on shallow soils over limestone bedrock in non-alvar settings, and usually includes numerous rock outcrops. There are usually several codominant trees, although one species may become dominant in any one stand.
  • Maple-basswood rich mesic forest (guide)
    A species rich hardwood forest that typically occurs on well-drained, moist soils of circumneutral pH. Rich herbs are predominant in the ground layer and are usually correlated with calcareous bedrock, although bedrock does not have to be exposed. The dominant trees are sugar maple, basswood, and white ash.
  • Oak-tulip tree forest (guide)
    A hardwood forest that occurs on moist, well-drained sites in southeastern New York. The dominant trees include a mixture of five or more of the following: red oak, tulip tree, American beech, black birch, red maple, scarlet oak, black oak, and white oak.
  • Pitch pine-oak-heath rocky summit (guide)
    A community that occurs on warm, dry, rocky ridgetops and summits where the bedrock is non-calcareous (such as quartzite, sandstone, or schist), and the soils are more or less acidic. This community is broadly defined and includes examples that may lack pines and are dominated by scrub oak and/or heath shrubs apparently related to fire regime.
  • Red cedar rocky summit (guide)
    A community that occurs on warm, dry, rocky ridgetops and summits where the bedrock is calcareous (such as limestone or dolomite, but also marble, amphibolite, and calcsilicate rock), and the soils are more or less calcareous. The vegetation may be sparse or patchy, with numerous lichen covered rock outcrops.
  • Rocky summit grassland (guide)
    A grassland community that occurs on rocky summits and exposed rocky slopes of hills. Woody plants are sparse and may be scattered near the margin of the community. Small trees and shrubs may be present at low percent cover.
  • Shale cliff and talus community (guide)
    A community that occurs on nearly vertical exposures of shale bedrock and includes ledges and small areas of talus. Talus areas are composed of small fragments that are unstable and steeply sloping; the unstable nature of the shale results in uneven slopes and many rock crevices.
  • Shallow emergent marsh (guide)
    A marsh meadow community that occurs on soils that are permanently saturated and seasonally flooded. This marsh is better drained than a deep emergent marsh; water depths may range from 6 in to 3.3 ft (15 cm to 1 m) during flood stages, but the water level usually drops by mid to late summer and the soil is exposed during an average year.
  • Shrub swamp (guide)
    An inland wetland dominated by tall shrubs that occurs along the shore of a lake or river, in a wet depression or valley not associated with lakes, or as a transition zone between a marsh, fen, or bog and a swamp or upland community. Shrub swamps are very common and quite variable.

Associated Species

  • Copperhead (Agkistrodon contortrix)
  • Racer (Coluber constrictor)
  • Eastern Ratsnake (Pantherophis spiloides)
  • Five-lined Skink (Plestiodon fasciatus)


New York State Distribution

Although widespread in the state as a whole, Timber Rattlesnakes are now found in isolated or semi-isolated populations in southeastern New York, the southern tier, and the peripheral eastern Adirondacks. Populations were once found on Long Island and in most mountainous and hilly areas of the state, except for the higher elevations of the Adirondacks, Catskills, and the Tug Hill Plateau.

Global Distribution

The Timber Rattlesnake ranges from central New England south to northern Florida and west to eastern Texas, central Oklahoma, eastern Kansas, southeastern Nebraska, southern and eastern Iowa, and southeastern Minnesota. The distribution is spotty along the western and northern edges of the range. Sizable populations still occur in the Appalachian Mountains from Pennsylvania though the Virginias, across eastern Kentucky and Tennessee to northeastern Alabama, in the Ouachita and Boston mountains of Arkansas and extreme eastern Oklahoma, in heavily wooded sections of the southeastern Coastal Plain from North Carolina to northeastern Florida and west to Louisiana and southern Arkansas, and in the Piedmont in the Uwharrie National Forest of central North Carolina and Pine Mountain of west-central Georgia (Martin, in Tyning 1992). The overwintering dens occur at elevations of up to about 5,000 feet in the southern Appalachians, 2,200 feet in southern New England, and about 1,300 feet in northeastern New York, Wisconsin, and Minnesota and individuals may range to higher elevations during the summer (Martin, in Tyning 1992).

Best Places to See

  • Timber rattlesnakes are currently on display at the Bear Mountain Trailside Museum in Bear Mountain, New York (http://nysparks.state.ny.us/parks/info.asp?parkID=55). (Rockland County)
  • As this species is vulnerable to illegal collection, no naturally occurring populations are listed.

Identification Comments

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.


In New York, Timber Rattlesnakes hibernate in communal dens, often with copperheads (also venomous), and other 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.


Timber Rattlesnakes mainly prey upon small rodents such as mice, chipmunks, and gray squirrels, but they will also take songbirds on occasion.

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 and reproducing in New York.

Similar Species

  • Copperhead (Agkistrodon contortrix)
    The 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 cross-bands, and lack of a rattle.
  • Eastern Massasauga (Sistrurus catenatus) (guide)
    In New York, the Eastern 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 Eastern 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).

Timber Rattlesnake Images


Timber Rattlesnake
Crotalus horridus Linnaeus, 1758

  • Kingdom Animalia
    • Phylum Craniata
      • Class Reptilia (Reptiles)
        • Order Squamata (Lizards, Snakes and Amphisbaenians)
          • Family Viperidae (Vipers and Pit Vipers)

Additional Resources


Barbour, R. W. 1971. Amphibians and reptiles of Kentucky. Univ. Press of Kentucky, Lexington. x + 334 pp.

Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp.

Brown, C. W., and C. H. Ernst. 1986. A study of variation in eastern timber rattlesnakes, Crotalus horridus Linnaeus (Serpentes: Viperidae). Brimleyana 12:57-74.

Brown, W. S. 1984. Background information for the protection of the timber rattlesnake in New York state. Bull. Chicago Herptetol. Soc. 19:94-97.

Brown, W. S. 1987. Hidden life of the timber rattler. National Geographic 172:128-138.

Brown, W. S. 1988. Timber rattlesnake: background information for protection as a threatened species in New York State. New York Herpetologoical Society Newsletter No. 115. 2 pp.

Brown, W. S. 1991. Female reproductive ecology in a northern population of the timber rattlesnake, Crotalus horridus. Herpetologica 47:101-115.

Brown, W. S. 1993. Biology, status, and management of the timber rattlesnake (Crotalus horridus): a guide for conservation. SSAR Herp. Circ. No. 22. vi + 78 pp.

Brown, W. S., D. W. Pyle, K. R. Greene, and J. B. Friedlander. 1982. Movements and temperature relationships of timber rattlesnakes (Crotalus horridus) in northeastern New York. J. Herpetol. 16:151-161.

Brown, W.S. and F.M. Maclean. 1983. Conspecific scent-trailing by newborn timber rattlesnakes, Crotalus horridus. Herpetologica 39(4):430-436.

Campbell, J. A., and E. D. Brodie, Jr., editors. 1992. Biology of the pit vipers. Selva, Tyler, Texas.

Chambers, R.E. 1983. Integrating timber and wildlife management. State University of New York, College of Environmental Science and Forestry and New York State Department of Environmental Conservation.

Choquette, Jonathan D. and Lindsey Valliant. 2016. Road mortality of reptiles and other wildlife at the Ojibway Prairie Complex
and Greater Park ecosystem in southern Ontario. Canadian Field-naturalist 130(1): 64–75.

Collins, J. T. 1982. Amphibians and reptiles in Kansas. Second edition. Univ. Kansas Mus. Nat. Hist., Pub. Ed. Ser. 8. xiii + 356 pp.

Collins, J. T. and J. L. Knight. 1980. Crotalus horridus. Catologue of American Amphibians and Reptiles. SSAR No. 47:1-2.

Conant, R. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Second Edition. Houghton Mifflin Company, Boston, Massachusetts. xvii + 429 pp.

Conant, R. and J. T. Collins. 1991. A field guide to reptiles and amphibians: eastern and central North America. Third edition. Houghton Mifflin Co., Boston, Massachusetts. 450 pp.

Conant, R., and J. T. Collins. 1998. A field guide to reptiles and amphibians: eastern and central North America. Third edition, expanded. Houghton Mifflin Co., Boston, Massachusetts. 616 pp.

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Martin, W. H. 1992c. Phenology of the timber rattlesnake (Crotalus horridus) in an unglaciated section of the Appalachian Mountains. Pages 259-277 in Campbell, J. A., and E. D. Brodie, Jr. Biology of the pit vipers. Selva, Tyler, Texas.

Martin, W. H. 1993c. Reproduction of the timber rattlesnake (Crotalus horridus) in the Appalachian Mountains. J. Herpetol. 27:133-143.

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About This Guide

This guide was authored by: Shaw, Hollie Y.

Information for this guide was last updated on: June 28, 2019

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Crotalus horridus. Available from: https://guides.nynhp.org/timber-rattlesnake/. Accessed June 23, 2024.