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Eastern Massasauga

Scientific Name: Sistrurus catenatus

New York Status: Endangered
Federal Status: Not Listed


Drawing of Eastern Massasauga

The massasauga rattlesnake is the smallest of the three venomous snakes found in New York State, the other two being the timber rattlesnake (Crotalus horridus) and the copperhead (Agkistrodon contortrix). Derived from the Chippewa language, "massasauga" translates to "great river-mouth" and probably refers to the snake's preference for wet habitats, including riverine bottomlands. The adult massasauga, also known as the "swamp rattler," is a stout-bodied snake with a broad head. It measures 18-40 inches in length. Average length is 27.5 inches. The body is distinctively marked with a row of large black or dark brown hourglass-shaped markings along the back and three rows of smaller dark spots on each side. The background coloration is gray or brownish-gray. A dark bar with a lighter border extends from the eye to the rear of the jaw. Some adults, however, are all black. This rattlesnake can also be identified by the nine large scales on the crown of the head, similar to most non-venomous snakes. The timber rattlesnake's head is covered with numerous small scales.

A rattlesnake's "rattle" is at the end of its tail. A unique structure, it is formed from loosely attached, hard, horny segments. A new segment is added each time the snake sheds. When the tail is vibrated, a distinct buzzing sound is produced, characteristic of a disturbed rattlesnake.

Life History

The breeding season generally takes place during May or June, but mating can occur almost anytime from late April until September. Young are born from mid-August to September. A litter of 3-19 snakes (typically 7-10), each measuring 6.5-9.5 inches in length, are produced every 2-3 years. Massasaugas give birth to live young; they do not lay eggs. The massasauga reaches sexual maturity in 3-4 years and may live for about 14 years.

In New York, massasaugas hibernate from late October through late April in low, wet areas, often under sphagnum hummocks. They do not hibernate in communal dens as do the other venomous species in New York. During the summer months, individuals may disperse into nearby woods and fields in search of prey. Although normally active during the daylight hours, massasaugas may resort to evening and nighttime activity to escape the mid-summer heat. The massasauga feeds primarily on small rodents, but may also take a variety of small animals including other snake species, shrews, and an occasional frog or nesting bird.

Distribution and Habitat

Map of Eastern Massasauga

Massasauga rattlesnakes range from central New York and southern Ontario west to the prairies of Iowa and Missouri. The eastern massasauga is strongly associated with wetlands across most of its range. Wet prairie is the preferred habitat in the west, bogs and swamps in the east. The northern populations in Ontario, Canada, around Georgian Bay are found in rock outcrop areas that are more similar to the habitat where we find timber rattlesnakes. Massasaugas frequent other wet, lowland habitats, including marshes and floodplains. Locations that provide open sunny areas with elevated hummocks for basking as well as shaded areas for retreat are ideal. The hummocks are also used as a place for bearing young and, most importantly, for hibernation during winter months. In the summer, the massasauga often moves to drier, upland areas.

Throughout most of its range, the distribution is decidedly disjunct, with many miles separating populations. Currently, there are only two known populations remaining in New York, both of which occur in boggy, forested wetlands with "open rooms" of low vegetation.


Post-glacial changes affecting habitat conditions worked against the massasauga, eliminating the preferred prairie habitats in the eastern half of the range. Loss of habitat to development and agriculture, unregulated hunting, and snake collecting have all contributed to the decline of this species. They are also killed because people fear snakes in general and mistakenly perceive them to be a threat. Naturally occurring succession plays an important role as well, continually reducing the amount and quality of suitable habitat left. The two remaining sites in New York are safe from development, though natural succession is making them less suitable as time goes by.

Management and Research Needs

Mark/recapture and radio-telemetry studies were initiated in the early 1980s to determine the status of this species in New York State. Experimental habitat management has also been Carried out. Studies have been conducted in a continuing effort to determine the size and habitat requirements of New York's two populations. Reproductive success is also being investigated. Succession has been identified as the major factor negatively affecting the massasauga. Brush cutting, prescribed burning and herbicide use are being studied as methods to improve the habitat. Captive rearing of young for release back into the wild is another possible means of enhancing populations.

Additional References

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

Conant, R. and J. T. Collins. 1998. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Third Edition Expanded. Houghton Mifflin Co., Boston.

Ernst, C. H. 1992. Venomous Reptiles of North America. Smithsonian Institution Press, Washington.

Harding, J. H. 1997. Amphibians and Reptiles of the Great Lakes Region. The University of Michigan Press, Ann Arbor. 378 pp.

Johnson, B. and V. Menzies, Eds. 1993. Proc. International Symposium and Workshop on the Conservation of the Eastern Massasauga Rattlesnake Sistrurus catenatus. Metro Toronto Zoo, West Hill Ontario.

Johnson, G. 1998. Habitat Management for the Eastern Massasauga in a Central New York Peatland. J. Wildl. Manage. 62:84-97

Klauber, L. M. 1972. Rattlesnakes: Their Habitat, Life Histories, and Influence on Mankind. Zoological Soc. of San Diego, Univ. of California Press, Berkeley.

Reinert, H. K. and W. R. Kodrich. 1982. Movements and Habitat Utilization by the Massasauga, Sistrurus catenatus catenatus. J. Herpetol. 16:162-171.

Seigel, R. A. 1986. Ecology and Conservation of an Endangered Rattlesnake, Sistrurus catenatus, in Missouri, U. S. A. Biol. Conserv. 35:333-346.

Drawing by Jean Gawalt

Map adapted from Conant and Collins (1998) and Harding (1997)

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