Few Idaho mammals are reported as often as the yellow-bellied marmot. Its 1,209 records reach 39 counties, with Twin Falls, Ada, and Canyon counties leading and heavy showings through the Snake River canyon country and the rocky ranges of the interior. Wherever Idaho stacks boulders next to grass, this animal is likely nearby.
Rock is the whole address
A yellow-bellied marmot needs two things side by side, a deep rock pile for shelter and a meadow for food. It dens beneath talus, lava outcrops, and boulder fields, then ventures out to graze grasses, flowers, and leaves through the growing season. Craters of the Moon National Monument holds colonies in its broken lava flows, while City of Rocks National Reserve, Castle Rocks State Park, and the granite country of Boise National Forest and the Frank Church-River of No Return Wilderness all furnish the same rocky footing.
Underground by October
Marmots are among the longest hibernators of any North American mammal, and Idaho’s calendar shows it plainly. Reports surge from March, peak in May and June as animals feed and sun themselves beside their burrows, collapse to almost nothing by September, and vanish entirely for November and December. A marmot can spend eight months of the year asleep underground, living off the fat it built during a short, busy summer.
Status in Idaho
NatureServe ranks the yellow-bellied marmot S4, Apparently Secure, in Idaho, and the species is native to the state. USGS NAS does not list it as nonindigenous here.
Full species profile
