Records of the southwestern jumping mouse in Montana all but vanish from October through April, then surge to 371 in July and 192 in August. Unlike most rodents, that dead zone genuinely tracks biology as much as observer effort: jumping mice are among North America’s most committed hibernators, sometimes sleeping eight or nine months a year, so there is very little to record outside the short window when they’re active.
The listed locations, Charles M. Russell National Wildlife Refuge, nearby prairie wildlife management areas, and the Missouri River corridor, all sit in the Missouri Breaks, a mix of grassland and river-bottom cover that matches the species’ preferred habitat closely.
No NatureServe state rank is on file for this species in Montana, only a USGS NAS note confirming it isn’t a nonindigenous introduction here. With 722 records logged, mostly through GBIF rather than iNaturalist, the state’s population reads as genuinely native but without a formal conservation-rank assessment yet.
Full species profile
