North Dakota’s olive-backed pocket mouse is a creature of the dry west. Billings and Stark counties, badlands and broken country along the Little Missouri, lead the reports, with Burleigh and Morton on the Missouri River close behind. Seventeen counties have produced records in all, nearly every one west of the river. This is a mouse of sandy soil and sparse grass, and western North Dakota is where that ground lies.
The record has a sharp seasonal edge. Reports appear in May, spike in July, and go quiet by fall. Pocket mice forage on warm nights and spend the cold months underground in torpor, so the summer crest is probably genuine biology, though warm months are also when people run trap lines. Reports measure looking as well as living.
North Dakota hasn’t assigned the mouse a formal state rank, and the IUCN lists the species as Least Concern. In a state where native prairie keeps shrinking, its strong showing in the badlands counties suggests the rugged, unplowed west remains its most reliable ground.
Full species profile
