Wyoming is home to 117 species of mammals, as rare as the spotted bat and the Preble's shrew, as common as the pronghorn antelope. Wyoming boasts the largest pronghorn population in North America and also supports the largest concentration of wintering Rocky Mountain bighorn sheep.
Because many mammals are nocturnal or reside in habitats which make them difficult to observe, biologists often look for tracks or skulls, trap animals or use other special techniques to determine the occurrence of a particular species. Although many mammals are active during daylight hours, the best time to observe most wildlife is early morning and late afternoon/early evening. Because of their size, secretive nature, and the habitats they occupy, the smaller mammals are often very difficult to observe.
The state is divided into six regions for checklist use: Northwest (NW), Northern Central (NC), Northeast (NE), Southwest (SW), Southern Central (SC), and Southeast (SE).
There are six abundance designations: 1=Rare, 2=Uncommon, 3=Common, 4=Abundant, 5=Peripheral (range limited to small portion), 6=Undetermined (verified but not documented adequately.)
There are eight types of habitat for mammals: FO=Coniferous and Deciduous Forests, SH=Shrubland, RI=Riparian, PR=Prairie, WL=Wetlands, AG=Agriculture Croplands, SF=Special Features, an ME=Meadows.
For an explanation of these habitats order your own copy of the actual checklist. The checklist on this website is the same as that distributed by the Wyoming Game and Fish Commission. You can obtain copies of the checklist for your own use by calling (307) 777-4538 or by sending a request to:
To access the checklist here, click on the navigation button above.