Species Assessment for the Midget Faded Rattlesnake (Crotalus viridis concolor) in Wyoming
The Colorado and Wyoming State Offices of the USDI Bureau of Land Management (BLM) each list the midget faded rattlesnake as a Sensitive Species. The BLM developed this designation to “ensure that any actions on public lands consider the overall welfare of these sensitive species and do not contribute to their decline.” Sensitive species management will include: determining the distribution and current habitat needs of sensitive species; incorporating sensitive species in land use and activity plans; developing conservation strategies; ensuring that sensitive species are considered in National Environmental Policy Act analyses; and prioritizing necessary conservation work (USDI Bureau of Land Management 2001).
The midget faded rattlesnake (Crotalus viridis concolor) has long been considered a subspecies of the western rattlesnake (C. viridis). This document will follow this convention, although there is some discussion of taxonomic revision at the species level that would categorize the midget faded rattlesnake as C. oreganos concolor. Midget faded rattlesnakes are a pale brownish gray, cream, or straw color. Blotches on the body are faded, sub-rectangular or sub-elliptical. As with most rattlesnakes, the most distinguishing feature is the rattle. Midget faded rattlesnakes are pit vipers, with the typical heat-sensing pits on each side of the head, between the eyes and mouth, used for detecting prey.
The midget faded rattlesnake mainly occupies the Colorado Plateau of eastern Utah, western Colorado, and southwestern Wyoming. Midget faded rattlesnakes are shy and inhabit rocky and arid basins. Exposed rock outcrops and ledges are important habitat features because they provide safe hibernacula, escape cover, and thermal cover.
While not listed as Threatened or Endangered by the U.S. Fish and Wildlife Service (USFWS), “take” of the midget faded rattlesnake is restricted in Wyoming by the Wyoming Game and Fish Department (WGFD). Although reliable population estimates have not been established, it is generally considered to be a rare taxon in Wyoming and across its range.