Built like a tiny kangaroo
Pick out a jumping mouse by its proportions. The hind feet are oversized, the tail runs longer than the head and body combined, and the coat carries a brassy yellow-brown wash along the sides with a darker stripe down the back. Adults measure roughly 8 to 10 inches from nose to tail tip, and well over half of that is tail. When startled it doesn’t run. It launches, covering ground in a series of erratic hops, then freezes in cover and becomes very hard to find again.
Its relatives make identification worth a second look. The western jumping mouse overlaps inland, and the recently split central Pacific jumping mouse takes over the southern part of the coastal range. Along the coast from Washington into British Columbia, though, a jumping mouse in a wet meadow is usually this one.
Wet ground, tall grass
This is a mouse of moisture. It keeps to streamside meadows, sedge marshes, alder thickets, and swampy field edges, places where the grass stays rank and the soil stays soft through summer. Records span from sea level up past 5,000 feet in the Cascades and Olympics, but the constant is damp ground with dense cover, not elevation.
Hibernation dominates its calendar. Like other jumping mice it can sleep more than half the year, curled below the frost line on stored fat rather than cached food. Seasonal reports show the shape of that life: sightings build through spring, crest in high summer, and collapse to nearly nothing from late fall into early spring. Some of the quiet months reflect a genuinely absent animal, asleep underground, rather than one that’s merely hard to see.
A new name on an old mouse
Taxonomy here moved recently. The mammal community long treated coastal jumping mice broadly, and newer work separates the northern Pacific animals from their southern relatives, leaving this species centered on Washington. Oregon carries a large body of records too, and the exact southern boundary of the species is still being worked out, so a jumping mouse from the Oregon coast may sit near the seam between the two.
For the reader, the practical point is simple: names in older field guides won’t always match current ones, and a record’s location now matters as much as its label.
Quiet but holding on
The IUCN rates it Least Concern, and damp coastal meadow remains widespread across its range. The pressures are the usual ones for a wetland-edge species: drained marshes, grazed-down streambanks, and developments that harden the soggy margins it needs. Reports stay steady across western Washington’s lowlands, which suggests a mouse that, for now, is keeping its footing in the wet corners people have left alone.
