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Photo © A.B. Sheldon
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 in an agricultural setting during the summer. Gravid females and juvenile timbers prefer to remain in open-canopy bluff prairies during the summer because of higher preferred body temperatures, but avoid overheating by taking advantage of various structures to provide shade, such as brush, trees or rock shelves. Timbers 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. Timbers primarily breed in August and females give birth the following mid-August or mid-September. Individual females in WI usually produce young only once every three to four years.
The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Timber Rattlesnake (Crotalus horridus). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.
Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.
| Summary Information | |
|---|---|
| State Status | SC/P |
| Federal Status in Wisconsin | none |
| State Rank | S2S3 |
| Global Rank | G4 |
| Tracked by NHI | Y |
| WWAP | SGCN |
A guidance document is not available at this time. Use the information from the other tabs and contact local biologists, as needed, to develop management and avoidance strategies.
Click to view a larger version. Please considering donating a photo to the Natural Heritage Conservation Program for educational uses. Photo use
Photo © John Kivikoski.
Timber Rattlesnake
Photo © A.B. Sheldon.
Timber Rattlesnake
Photo © A.B. Sheldon.
The timber rattlesnake is now very rare in the Western Prairie due to past persecution and habitat loss.
Photo by Armund Bartz, WDNR.
Timber rattlesnake - gray phase.
Photo by Armund Bartz, WDNR.
The table below lists the natural communities that are associated with Timber Rattlesnake. Only natural communities for which Timber Rattlesnake is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.
| Natural community | Score |
|---|---|
| Dry Cliff | 3 |
| Dry Prairie | 3 |
| Eastern Red-cedar Thicket | 3 |
| Oak Opening | 3 |
| Oak Woodland | 3 |
| Pine Relict | 3 |
| Sand Barrens | 3 |
| Sand Prairie | 3 |
| Southern Dry Forest | 3 |
| Southern Dry-mesic Forest | 3 |
| Southern Mesic Forest | 3 |
| Bedrock Glade | 2 |
| Dry-mesic Prairie | 2 |
| Floodplain Forest | 2 |
| Mesic Prairie | 2 |
| Southern Hardwood Swamp | 2 |
The table below lists the ecological landscape association scores for Timber Rattlesnake. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.
| Ecological landscape | score |
|---|---|
| Western Coulee and Ridges | 3 |
| Western Prairie | 3 |
| Central Sand Hills | 1 |
| Southwest Savanna | 1 |
Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.
* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.
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 WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.