The IUCN Red List, the main resource for global information conservation status, has nine conservation categories.
IUCN has updated their conservation categories and corresponding criteria twice since they began, most recently in 2001. They also reevaluate animals on a regular basis.
United States: U.S. Fish and Wildlife Service: Endangered Species Program
United States and Canada: NatureServe: NatureServe Explorer
All US States will have a fish and wildlife department. Search for the state you are interested in, along with the words department and wildlife.
Image of Northern Idaho Ground Squirrel, courtesy of USFWS Endangered Species
Status: Threatened
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