Scientific Name Common Name Global Rank State Rank Federal Status WI Status Animal Group

Timber Rattlesnake (Crotalus horridus)








Photo by A.B. Sheldon


Counties with Mapped NHI Occurrences

Timber Rattlesnake (Crotalus horridus) is a Special Concern species and a Protected Wild Animal. Adult males and non-gravid adult females prefer deciduous forests and woodland edges during the summer. Gravid females and juveniles prefer to remain in open-canopy bluff prairies during the summer because of higher preferred body temperatures, but avoid overheating by taking advantage of such things as brush, trees, and rock shelves to provide shade. Timber rattlesnakes emerge from hibernation as early as April 1 but may continue to emerge well into June. They remain active until as late as mid-October, females that gave birth that year remain active longer than other individuals. They primarily breed in August and females give birth about a year later. In Wisconsin, females typically produce young only once every 3-4 years.


Species of Greatest Conservation Need (SGCN) are associated with habitats (or natural communities) and places on the landscape. Understanding relationships among SGCN, natural communities and ecological landscapes help us make decisions about issues affecting SGCN and their habitat and how to respond. Download the Wildlife Action Plan association score spreadsheet to explore rare species, natural communities and ecological landscape associations

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the Wisconsin Wildlife Action Plan because lack of information can threaten our ability to successfully preserve and care for natural resources.