The yellow-bellied marmot is a common sight across Colorado’s high country. Open occurrence databases hold 6,288 records for the marmot in Colorado, most of them iNaturalist photos, more than any other state in its range.
Where and when to see marmots in Colorado
Head for the rocky slopes and boulder fields of the high country; marmots need loose talus for escape cover right beside alpine or subalpine meadow. Sightings cluster at Rocky Mountain National Park, Mount Blue Sky (Mount Evans), and Rio Grande National Forest, and the season is short and unmistakable. Numbers build fast through spring, spike at midsummer, then fall off a cliff. That long winter silence is not the marmots leaving, it is the marmots asleep, the fingerprint of a rodent that hibernates for roughly eight months of the year.
Status in Colorado
The yellow-bellied marmot is native to Colorado and secure here, ranked S5 (secure) by NatureServe and least concern by the IUCN. Coloradans know it as the rockchuck or whistle pig, for the sharp alarm call that sends a whole colony diving into the rocks when a coyote, badger, or golden eagle appears.
Common questions
Why are marmot reports scarce in winter? They hibernate. Records fall to near nothing from autumn through early spring and rebound as colonies emerge to feed, so the animal that dominates a July hillside is simply underground for much of the year.
Where is the best place to see one? Any high, rocky slope with meadow nearby. Rocky Mountain National Park and the alpine reaches of the state’s national forests are reliable.
Full species profile
