Crotalus willardi obscurus NatureServe Explorer Species Reports — NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.
ITIS Reports — ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.
FWS Digital Media Library — The U.S. Fish and Wildlife Service’s National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video. Common names: New Mexico ridge-nosed rattlesnake. Animas ridge-nosed rattlesnake, Crotalus willardi obscurus is a venomous pitviper subspecies found in northwestern Mexico and the Southwestern United States.This is the only venomous snake listed as Threatened by the U.S. Fish and Wildlife Service. The species C. willardi is classified as Least Concern on the IUCN Red List of Threatened Species (v3.1, 2001). Species are listed as such due to their wide distribution, presumed large population, or because they are unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend was stable when assessed in 2007.
Although four of the five subspeciesare secure, the New Mexico ridge-nosed rattlesnak