Eastern Massasauga

Sistrurus catenatus (Rafinesque, 1818)

Eastern Massasauga
Tom Bell, NYS DEC

Reptilia (Reptiles)
Viperidae (Vipers and Pit Vipers)
State Protection
Listed as Endangered by New York State: in imminent danger of extirpation in New York. 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
Listed as Threatened under the Federal Endangered Species Act
State Conservation Status Rank
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
Vulnerable globally - At moderate risk of extinction due to rarity or other factors; typically 80 or fewer populations or locations in the world, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines.


Did you know?

Unlike most rattlesnakes, Eastern Massasauga do not hibernate with other snakes (Johnson 1995).

State Ranking Justification

New York State Department of Environmental Conservation studies indicate a sharp population decline since the 1960s which led to listing this species as state endangered in 1983 (Johnson and Breisch 1999). The population estimate is approximately 200 snakes excluding neonates in New York (Krofta 2007). Krofta (2007) suggests a stable population consists of a minimum of 200-300 adults and subadults. Therefore, neither population in New York is considered stable. Wintering habitat is largely protected, however, succession is a threat (Johnson 1995, New York State Department of Environmental Conservation 2019, Szymanski 1998).

Short-term Trends

The population size is approximately 200 snakes, excluding neonates (Krofta 2007). Krofta (2007) suggests a minimum population of 200-300 adults and subadults at each site to be considered stable. Based on this minimum, both sites in New York are vulnerable. Natural succession is a significant threat. Reproduction has been confirmed at both sites.

Long-term Trends

Historically, this species was once considered abundant at known locations (Johnson et al. 2000). New York State Department of Environmental Conservation studies indicate a sharp population decline since the 1960s (Johnson and Breisch 1999). The species was listed as state endangered in 1983 (Johnson and Breisch 1999). Historically, snakes were killed in large numbers throughout its range (Szymanski 1998).

Conservation and Management


Anthropogenic factors are the most significant threat to Eastern Massasauga populations. Development, agriculture, unregulated hunting, snake collecting are all present threats. Some people kill snakes due to fear during accidental encounters. Gestating areas and hibernacula in New York are on protected land which offers some protection. However, natural succession from open, natural wetlands to a closed canopy is a significant threat at both sites (Johnson 1995, New York State Department of Environmental Conservation 2019, Szymanski 1998). Upland habitats do not have the same protections as wetlands and risk fragmentation between seasonally used habitats. Unregulated collecting was legal until the 1970s in parts of NY (Johnson 1995).

Conservation Strategies and Management Practices

Transitional peatlands are critical for hibernation and gestation. It may be necessary to create site-specific management plans. In New York State, consultation with the Department of Environmental Conservation is needed. The suggested goal is to have at least 50% of the habitat open with vegetation less than 0.5 meter tall (Johnson et al. 2000). Shoemaker et al. (2007) recommends that a closed canopy should make up 0% to 25% of the wetland habitat and snakes have areas for “cryptic” basking. Prescribed burns and mechanical treatments are used to maintain open habitats (Johnson and Breisch 1999, Johnson et al. 2000, Western Pennsylvania Conservancy 2019). Johnson et al. (2000) recommend mechanical treatment in peatlands and some wooded areas, which includes cutting, brush-hogging, mowing, and disking. Mowers should be positioned 4 to 6 inches above ground. The best time to mow is while the snakes are hibernating (Johnson et al. 2000, Western Pennsylvania Conservancy 2019) or at least when snakes are less active, from 11am to 3pm (Johnson et al 2000). Disking should be used as a last result because it can kill a lot of snakes and damage hibernation sites. Studies should be conducted to find as many hibernating sites as possible because altering these sites could negatively impact the population. Note that some plants may respond to cutting by growing more densely (Johnson and Breisch 1999). These management techniques can be expensive and time consuming because the work needs to be repeated after substantial regrowth. Herbicides can help increase the intervals between treatments, however little is known about how herbicides affect snakes (Johnson et al. 2000). If used, the best time to apply herbicides is at the end of the growing season, just before the leaves fall (Johnson et al. 2000). Herbivory can help control vegetation growth and may be suitable in some areas (Johnson and Briesch 1999). Management plans should include strategies that includes habitats for small mammals and crayfish (Johnson et al. 2000). In addition, continued monitoring is advised to determine effectiveness of management actions, including monitoring at control sites (Shoemaker et al. 2008). Krofta (2007) points out that any habitat management actions have potential to have negative impacts on the population. A minimum population of 200-300 adults and subadults is considered stable (Krofta 2007).

Roads may bisect seasonally used habitats. Mortality increases when snakes attempt to cross roads. Corridors may be useful in areas where suitable habitat has been fragmented. Seasonally reducing speed limits when snakes are active should also be considered. Temporary road closures are another option, especially on managed lands (Johnson et al. 2000). Many sustainable agricultural practices can benefit Eastern Massasauga populations (Western Pennsylvania Conservancy 2019).

Educational materials that explain Eastern Massasauga biology might be useful in areas where the public has concerns about venomous snakes. Outreach to landowners concerning practices that could benefit them and the snakes is also an option to help maintain or expand suitable habitat.

Research Needs

Additional studies are needed concerning population size, density estimates, age-specific mortality rates, and neonate and subadult movement patterns.



There are three general habitat characteristics throughout the Eastern Massasauga range: (1) a mix of open, sunny areas and some shade for thermoregulation, (2) water table near the surface that does not freeze for hibernation, and (3) variable elevation for foraging (Szymanski 1998). In New York, peatlands are a crucial portion of Eastern Massasauga habitat as they are needed for hibernation and gestation (Johnson 1995). Eastern Massasauga use different habitat seasonally. In the spring and fall, snakes are typically found in wet meadow habitats. Snakes move upland during the summer months (Johnson et al. 2000) in search of prey (Johnson 1995). During the winter, these snakes hibernate individually in sphagnum hummocks and root systems where the soil is saturated, but not inundated. (Harvey and Weatherhead 2006, Johnson 1995, Johnson et al. 2000).

Associated Ecological Communities

  • Black spruce-tamarack bog (guide)
    A conifer forest that occurs on acidic peatlands in cool, poorly drained depressions. The characteristic trees are black spruce and tamarack; in any one stand, either tree may be dominant, or they may be codominant. Canopy cover is quite variable, ranging from open canopy woodlands with as little as 20% cover of evenly spaced canopy trees to closed canopy forests with 80 to 90% cover.
  • Marl fen (guide)
    A wetland that occurs on a bed of marl. Marl is a whitish substance that is deposited from water that has a lot of calcium dissolved in it. The whitish substance is calcium carbonate, people used to harvest marl to lime agricultural fields. The marl substrate is always saturated, may be flooded, and has a very high pH, generally greater than 7.5. The main source of water is always groundwater. The plants are often sparse and stunted. Marl fens may occur as small patches within a rich graminoid fen.
  • Northern white cedar rocky summit (guide)
    A community that occurs on cool, dry, rocky ridgetops and summits where the bedrock is calcareous (such as limestone or dolomite), and the soils are more or less calcareous. The vegetation may be sparse or patchy, with numerous rock outcrops. The species have predominantly boreal distributions.
  • Rich graminoid fen (guide)
    A wetland of mostly grasses usually fed by water from highly calcareous springs or seepage. These waters have high concentrations of minerals and high pH values, generally from 6.0 to 7.8. Plant remains do not decompose rapidly and these grasses usually grow on older, undecomposed plant parts.


New York State Distribution

Central New York represents the easternmost extent of the Eastern Massasauga range. This species is confined to two sites in the state: one in Onondaga County and one in Genesee County. Historically, this species was reported from other sites in western New York, but none have been confirmed.

Global Distribution

This species range extends from southern Ontario and western New York west across Michigan and southern Wisconsin to southeastern Minnesota, eastern Iowa, and eastern Missouri, south to southern Illinois, central Indiana, southern Ohio, and western Pennsylvania. A disjunct population exists at the eastern end of Michigan's Upper Peninsula (Conant and Collins 1991). Subspecies catenatus may intergrade with subspecies tergeminus in north-central Missouri (Beltz, in Johnson and Menzies 1993). The historical range in Canada extended throughout the mesic prairie and wetlands that formerly were common in southwestern and west-central Ontario (Johnson and Menzies 1993).

Recent evidence (see Szymanski 1998) indicates that Eastern Massasaugas in all of Missouri and Iowa likely represent subspecies catenatus , so all populations north and east of the Missouri River probably should be regarded as S. c. catenatus. This is the circumscription used by the USFWS (2009) for the eastern distinct population segment of Sistrurus catenatus.

Best Places to See

  • As this species is vulnerable to illegal collection and persecution, no naturally occurring populations are listed.

Identification Comments

Identifying Characteristics

Eastern massasauga is a stout, thick-bodied snake that ranges from 45 to 100 cm (18 to 40 in) in length. Females are slightly larger than males. The head is broad and heart-shaped with nine large scales on the crown. A bar with a light border extends from the eye to the rear of the jaw. Body color ranges from light brown to gray with a row of dark brown to black hourglass-shaped blotches down the back. There are three rows of smaller blotches on each side. The belly is usually black with light mottling. Some individuals are all black. Young snakes are similar, but colors are more vivid. This species has a series or loose scales at the end of the tail that vibrates (rattles). Newborn snakes have a single button for a rattle. This species is a mild-mannered snake that rarely strikes (Western Pennsylvania Conservancy 2019).

Characters Most Useful for Identification

Two key characteristics to help identify Eastern Massasauga are the nine large scales on the crown and the rattle. In New York, this species does not occur at the same locations as timber rattlesnakes, the only other rattlesnake species in the state.

Best Life Stage for Proper Identification

Adults are the best stage for identification, but juvenile appearance is similar.


Eastern Massasauga hibernate in pockets associated with wetlands. They do not aggregate with other snakes as other venomous snakes do. When they emerge in the spring, males and non-gravid females remain near their hibernation site for 10 to 20 days (Johnson 1995, Johnson et al. 2000). Gravid females remain in wetlands until 10 to 12 days after parturition (Johnson 1995). Females give birth to live young approximately every two years. The typical broods size ranges from 3 to 19 young (Johnson 1995). Hunting occurs during the day with the exception of periods of hot weather (Johnson et al. 2000). Sexual maturity is reached at approximately 3 to 4 years and snakes can live for about 14 years (New York State Department of Environmental Conservation 2019).


Preferred prey are small mammals and sometimes other vertebrates.

Best Time to See

Eastern Massasauga can be found from late May to October. Males and non-gravid female use similar upland habitat while gravid females remain close to hibernacula. They are active during the day, but will hunt at night when it's hot outside. Courtship and mating occurs August through September and females give birth to live young from mid-August to mid-September the following year (Johnson 1995).

  • Present
  • Active
  • Reproducing

The time of year you would expect to find Eastern Massasauga present, active, and reproducing in New York.

Similar Species

  • Eastern Hog-nosed Snake (Heterodon platirhinos)
    Eastern Hog-nosed Snake is a medium-sized, thick-bodied snake like Eastern Massasauga. However, Eastern Hog-nosed Snake has an upturned snout and lacks a rattle. When threatened, this species flattens it head, similar to a cobra or flips over and plays dead.
  • Milksnake (Lampropeltis triangulum)
    Milksnake is a thin-bodied snake with a 'V' or 'Y' -shaped mark on the head or neck and smooth scales. There is no rattle.

Eastern Massasauga Images


Eastern Massasauga
Sistrurus catenatus (Rafinesque, 1818)

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


  • Sistrurus catenatus catenatus (Rafinesque, 1818)

Comments on the Classification

Subspecies no longer recognized. Former subspecies S. c. catenatus was the only subspecies in New York and the Northeast.

Additional Resources


Breisch, A.R. 1984. The eastern massasauga, in danger of extinction. Conservationist 39(3):35.

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.

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.

DeGraaf, R.M. and D.D. Rudis. 1981. Forest habitat for reptiles and amphibians of the northeast. United States Department of Agriculture, Forest Service Eastern Region, Milwaukee, WI. 239 pp.

Eckel, E.C. and F.C. Paulmier. 1902. Catalogue of New York reptiles and batrachians. New York State Museum Bull. No. 51. Albany, NY.

Endangered Species Unit. 1986. Monthly highlights - 16 July to 15 August 1986. Endangered Species Unit. New York State Department of Environmental Conservation. Delmar, NY.

Endangered Species Unit. New York State Department of Environmental Conservation. Wildlife Resources Center. Delmar, NY. 12054. (518) 439-7635.

Ernst, C. H. 1992. Venomous reptiles of North America. Smithsonian Institution Press, Washington, D.C. ix + 236 pp.

Ernst, C. H., and R. W. Barbour. 1989b. Snakes of eastern North America. George Mason Univ. Press, Fairfax, Virginia. 282 pp.

Gloyd, H. 1940. The rattlesnakes. Chicago Academy Science, Special Publication No. 4.

Harvey, D. S., and P. J. Weatherhead. 2006. Hibernation site selection by eastern massasauga rattlesnakes (Sistrurus catenatus catenatus) near their northern range limit. Journal of Herpetology 40:66-73.

Johnson et al. 2000. The Eastern Massasauga Rattlesnake: A Handbook for Land Managers. U.S. Fish and Wildlife Service, Fort Snelling, MN 55111-4056 52 pp. + appdx.

Johnson, B., and V. Menzies, editors. 1993. International symposium and workshop on the conservation of the eastern massasauga rattlesnake Sistrurus catenatus catenatus. Metropolitan Toronto Zoo, West Hill, Ontario, Canada. 141 pp.

Johnson, G. 1990. Conservation efforts for the eastern massasauga at the Cicero Swamp Wildlife Management Area, New York. Natural Areas Journal 10:219-220.

Johnson, G. 1992. Swamp rattler. The Conservationist (NYSDEC), Spet.-Oct. 1992, pp. 26-33.

Johnson, G. 2000. Spatial ecology of the eastern massasauga (Sistrurus c. catenatus) in a New York peatland. Journal of Herpetology 34:186-192.

Johnson, Glenn and Alvin Breisch. 1999. The eastern massasauga rattlesnake in New York: Occurrence and habitat management. Metro Toronto Zoo. Rattlesnake Symposium. https://www.researchgate.net/publication/237717107_THE_EASTERN_MASSASAUGA_RATTLESNAKE_IN_NEW_YORK_OCCURRENCE_AND_HABITAT_MANAGEMENT

Johnson, Glenn. 1995. Spatial ecology, habitat preference, and habitat management of the eastern massasauga, Sistrurus catentatus catenatus in a New York weakly-minerotrophic peatland. Unpublished Ph.D. dissertation State University of New York College of Environmental Science and Forestry, Syracuse, New York. 221 pp.

Klauber, L. M. 1972. Rattlesnakes: their habits, life histories, and influence on mankind. Second edition. Two volumes. Univ. California Press, Berkeley.

Krofta, Alex T. 2007. Estimating abundance for a declining population of the eastern massasauga rattlesnake, Sistrurus catenatus catenatus, in Cicero, NY: application of multiple methods. Thesis.

Moesel, J. 1918. The prairie rattleer in western and central New York. Copeia 58:67-88.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

New York Natural Heritage Program. New York State Department of Environmental Conservation. 625 Broadway, 5th floor. Albany, NY 12233-4757. (518) 402-8935.

New York State Department of Environmental Conservation. 1985. Checklist of the amphibians, reptiles, birds, and mammals of New York State, including their protective status. Nongame Unit. Wildlife Resources Center. Delmar, NY.

Prior, K. A., and P. J. Weatherhead. 1994. Response of free-ranging eastern massasauga rattlesnakes to human disturbance. J. Herpetol. 28:255-257.

Reilly, E.M. 1955. Snakes of New York. New York State Conservationist: 22-23 and 26.

Reinert, H. K., and W. R. Kodrich. 1982. Movements and habitat utilization by the massasauga, Sistrurus catenatus catenatus. J. Herpetol. 16:162-171.

Shoemaker, Keven T. Alex Krofta, and James Gibbs. 2008. Population status and management needs of the massasauga rattlesnake (Sistrurus C. catenatus) in New York State. Final Report.

Szymanski, Jennifer. 1998. Status assessment for Eastern Massasauga (Sistrurus c. catenatus). U.S. Fish and Wildlife Service.

U.S. Fish and Wildlife Service (USFWS). 2009. Sistrurus catenatus catenatus species assessment and listing priority assignment form. USFWS Region 3. 13pp.

Vogt, R. C. 1981c. Natural history of amphibians and reptiles of Wisconsin. Milwaukee Public Museum. 205 pp.

Weatherhead, P. J., and K. A. Prior. 1992. Preliminary observations of habitat use and movements of the eastern massasauga rattlesnake (Sistrurus c. catenatus). J. Herpetol. 26:447-452.

Western Pennsylvania Conservancy. 2019. Species at risk: Eastern Massasuaga rattlesnake. Accessed on June 24, 2019 from https://waterlandlife.org/wildlife-pnhp/species-at-risk-in-pennsylvania/eastern-massasauga-rattlesnake/


About This Guide

This guide was authored by: Shaw, Hollie Y.

Information for this guide was last updated on: July 11, 2019

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Sistrurus catenatus. Available from: https://guides.nynhp.org/eastern-massasauga/. Accessed April 17, 2024.