Washington mammals

Northern Grasshopper Mouse in Washington

Onychomys leucogaster

Native to Washington S3 Vulnerable in Washington

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

Northern grasshopper mouse walking beside desert grassNorthern grasshopper mouse resting low among dry stemsNorthern grasshopper mouse on sandy soil from above
Photo: Logan Ediger · CC BY 4.0Northern grasshopper mouse walking beside desert grassPhoto: Stephanie Dolrenry · CC BY-SA 4.0Northern grasshopper mouse resting low among dry stemsPhoto: Cole Wolf · CC BY 4.0Northern grasshopper mouse on sandy soil from above

Northern Grasshopper Mouse in Washington, by the numbers

Occasional in Washington 59th most recorded of 145 mammals logged in Washington

135 occurrence records

Records from 2000–2026.

135 total records count every Washington occurrence from GBIF and iNaturalist; the monthly chart covers the 134 records with a full observation date.

When to look for the Northern Grasshopper Mouse in Washington

Most sightings fall in July to August.

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

Monthly Washington records (table)
MonthRecords
January0
February3
March2
April19
May3
June17
July36
August33
September3
October4
November9
December5

Monthly northern grasshopper mouse occurrence records (iNaturalist and GBIF) in Washington, 2000–2026.

Seasonality

Year-round in Washington, with recorded sightings peaking in July–August.

Occurrence map

Where Northern Grasshopper Mouse has been recorded in Washington

135 records mapped · zoom and drag to explore

135 Washington records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Juniper Dunes Wilderness Area 3

Protected places with the most northern grasshopper mouse 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 Washington

CountyRecords
Benton County 48
Walla Walla County 32
Franklin County 19
Grant County 16
Adams County 15
Yakima County 4
Whitman County 1

The complete county distribution, spread across 7 Washington counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

In Washington, the northern grasshopper mouse is a shrub-steppe animal, full stop. Every mapped county, Benton, Walla Walla, Franklin, Grant, Adams, Yakima, and Whitman, lies east of the Cascades in the Columbia Basin, and Benton County alone supplies more than a third of the reports. That’s Hanford Reach country: big, open, sandy, and dry, with room for a mouse that makes its living hunting insects and other rodents on bare ground.

The seasonal rhythm is strong. Reports rise in April, build through early summer, and top out in July and August before tapering into fall. A nocturnal hunter of shortgrass ground is easiest to find on warm nights, so the summer crest mixes real activity with the season when people are out looking.

Even with a healthy record count, NatureServe ranks the mouse S3, vulnerable in Washington. Shrub-steppe is one of the state’s most converted landscapes, and the places that still hold it, Hanford Reach, the Columbia National Wildlife Refuge, Juniper Dunes, are exactly where the reports come from.

Occurrence data from GBIF.

Northern grasshopper mouse walking beside desert grass
Full species profile Northern Grasshopper Mouse Onychomys leucogaster Size 12.7 cm5 in Weight 33 g1.2 oz Lifespan Up to 5.6 yr View the full profile

More mammals in Washington 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"