I find these 2 species very difficult to distinguish. The ground squirrel above was photographed at Fossil Butte National Monument. It appeared “buffier” than the Uinta ground squirrels I see at Yellowstone and the Teton Valley (in this area, there are no Wyoming GS).
When the National Park Service surveyed wildlife, they identified these as Richardson’s ground squirrels. The Wyoming ground squirrel has since been split from Richardson’s (although the NPS signage and species list still lists them as “Richardson’s”).
Seedskadee National Wildlife Refuge lists Wyoming GS as “common” and Uintas as “occasional.” The ground squirrels I saw there looked pretty much the same as the one in the photo above.
So it would seem the one above is a Wyoming ground squirrel. But really, how do you tell when ranges overlap? Any pointers?