California mammals

Long-tailed Pocket Mouse in California

Chaetodipus formosus

Native to California SNR Unranked in California

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

Long-tailed Pocket Mouse in California, by the numbers

Common in California 81st most recorded of 241 mammals logged in California

3,552 occurrence records
32 with iNaturalist photos

Records from 2000–2026.

3,552 total records count every California occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 300; the monthly chart covers the 3,510 records with a full observation date.

When to look for the Long-tailed Pocket Mouse in California

Most sightings fall in March to June.

3,510 California occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence.

Monthly California records (table)
MonthRecords
January28
February180
March610
April664
May505
June408
July230
August395
September157
October196
November71
December66

Monthly long-tailed pocket mouse occurrence records (iNaturalist and GBIF) in California, 2000–2026.

Seasonality

Year-round in California, with recorded sightings peaking in March–June.

Occurrence map

Where Long-tailed Pocket Mouse has been recorded in California

300 records mapped · zoom and drag to explore

300 California records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Death Valley National Park 508
Inyo Mountains Wilderness Area 96
Mojave National Preserve 76
Golden Valley Wilderness Area 64
Mecca Hills Wilderness Area 28
Turtle Mountains Wilderness Area 27
Mojave Trails National Monument 23
Joshua Tree National Park 21

Protected places with the most long-tailed pocket 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 California

CountyRecords
Inyo County 1,258
San Bernardino County 1,132
Riverside County 392
Kern County 312
Imperial County 220
San Diego County 148
Los Angeles County 18
Lassen County 15
Mono County 15
Tulare County 13
Fresno County 1
Other localities 28

The complete county distribution, spread across 11 California counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Long-tailed Pocket Mouse records reflect California’s dry interior, where sandy flats, open scrub, grassland, and desert basins form a patchwork rather than one continuous habitat. The Central Valley, Mojave Desert, and eastern rain-shadow valleys differ greatly in soil and vegetation.

Agriculture, roads, and expanding towns have broken up many lowland sites, especially in the San Joaquin Valley. Reports don’t measure abundance, and the scarcity of nighttime surveys can leave suitable-looking ground with few or no mapped observations.

The California record set combines 32 research-grade community observations with 3,545 museum and survey records. Monthly patterns can also reflect weather and observer activity, so they shouldn’t be treated as a direct count of animals.

Occurrence data from iNaturalist and GBIF.

More mammals in California 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"