Colorado mammals

Muskrat in Colorado

Ondatra zibethicus

Native to Colorado S5 Secure in Colorado

Not listed as nonindigenous in Colorado by USGS NAS; native to its Colorado range.

IUCN Red List status

  1. LC
  2. NT
  3. VU
  4. EN
  5. CR
  6. EW
  7. EX

LC – Least Concern

Widespread and abundant; not at risk.

Muskrat in Colorado, by the numbers

Common in Colorado 22nd most recorded of 154 mammals logged in Colorado

1,355 occurrence records
1,349 with iNaturalist photos
Jul 5, 2026 Last seen in Colorado

Records from 2000–2026.

1,355 total records count every Colorado occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 300; the monthly chart covers the 1,312 records with a full observation date.

When to look for the Muskrat in Colorado

Most sightings fall in April to July.

1,312 Colorado occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence.

Monthly Colorado records (table)
MonthRecords
January85
February43
March119
April213
May175
June133
July136
August96
September56
October56
November106
December94

Monthly muskrat occurrence records (iNaturalist and GBIF) in Colorado, 2000–2026.

Seasonality

Year-round in Colorado, with recorded sightings peaking in April–July.

Occurrence map

Where Muskrat has been recorded in Colorado

300 records mapped · zoom and drag to explore

300 Colorado records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Rocky Mountain National Park 84
Chatfield State Park 18
White River National Forest 9
Barr Lake 8
Roosevelt National Forest 6
San Juan National Forest 6
Camp Hale - Continental Divide National Monument 5
Environmental Learning Center 5

Protected places with the most muskrat sightings, from the USGS Protected Areas Database plus named mountain ranges, good spots to look, not a full breakdown, so they don't sum to the total.

Where it's recorded in Colorado

CountyRecords
Larimer County 207
Arapahoe County 204
Jefferson County 194
Boulder County 171
Denver County 116
Adams County 72
El Paso County 51
Weld County 25
Summit County 23
Grand County 19
Mesa County 18
La Plata County 16
39 other counties 239

The complete county distribution, spread across 51 Colorado counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

The muskrat is a wetland rodent in Colorado. Open occurrence databases hold 1,355 Colorado records, 1,349 of them iNaturalist observations, a strong total for an animal that spends most of its life low in the water with only a blunt head and a narrow scaly tail showing.

Where muskrats turn up in Colorado

Muskrats need standing or slow water with cattails, sedges, and soft banks to burrow into, so the records track wetlands, not elevation. The heaviest counts come off the northern Front Range and the metro corridor, where Larimer, Arapahoe, Jefferson, Boulder, and Denver counties pack in ponds, reservoirs, ditches, and stormwater basins full of emergent plants. Farther out, the animal follows the South Platte to Chatfield State Park and Barr Lake, and turns up in the ponds inside Rocky Mountain National Park and the spring-fed marshes of the San Luis Valley around Monte Vista. In the drier basins and high country it thins out fast, holding only where irrigation and reservoirs keep marsh vegetation alive.

A year-round animal that never truly disappears

Unlike the state’s marmots or bears, the muskrat does not hibernate. It stays active straight through the Colorado winter, swimming under the ice between its bank burrow and submerged feeding platforms and pushing up small breathing mounds of cut vegetation. The gentle spring rise in observations is an observer effect more than a real one: ice clears, cattails green up, and paddlers and birders are out along the water again. The animal itself is there in January, just harder to see.

Status in Colorado

The muskrat is native to Colorado and secure here, ranked S5 by NatureServe and Least Concern by the IUCN. Any pond, reservoir edge, or cattail ditch with year-round water and soft banks is a reasonable place to look. Watch for the side-to-side wake and the low, chunky brown swimmer that stops to feed right at the waterline.

Muskrat in other states

Muskrat range map (all states)

More mammals in Colorado in the atlas

Data & sources

The data and visualizations on this page draw on these open sources:

  • GBIFCC-BY 4.0occurrence records behind the range map, elevation, and record counts
  • iNaturalistCC0 / CC-BY / CC-BY-SAobservations, photos, and audio recordings
  • NatureServe ExplorerCC-BYthe state conservation rank
  • IUCN Red Listattributed factthe global conservation status
  • USGS NASpublic domainnative / introduced status
  • Natural Earthpublic domainthe relief basemap
  • USFSpublic domainnational-forest boundaries
  • USGS Protected Areas Databasepublic domainthe named parks, forests, and refuges behind "notable places to look"