The montane shrew, also called the dusky shrew, is one of Colorado’s most-recorded small mammals. Open occurrence databases hold 1,753 Colorado records, drawn almost entirely from small-mammal survey specimens, an unusually rich tally for an animal few people ever see alive.
A shrew of the moist high forest
Where Merriam’s shrew keeps to dry basins, the montane shrew is the wet-forest shrew of the Colorado mountains. Its records climb into the conifer and aspen country of the high central and western counties, heaviest around Boulder, Larimer, and Gunnison, wherever damp soil, heavy leaf litter, and streamside undergrowth sit beneath the canopy. That is the whole story of its distribution here: find moist ground under mountain trees and this shrew has a good chance of being there. It is one of the smallest mammals in the West, light enough to curl inside a teaspoon, and a live one glimpsed in the litter is usually just crossing between cover.
Hunting around the clock, all year
The montane shrew does not hibernate, does not fatten for winter, and never rests for long. A heart beating hundreds of times a minute burns through fuel so fast the animal has to eat every few hours, day and night, through every season. Most of its diet is soft-bodied invertebrates, beetle larvae, worms, and spiders picked from rotting wood and leaf litter by smell and touch, rounded out by carrion it will not pass up. Its abundance in the record reflects that constant, ground-level foraging in exactly the moist habitats where survey traps get set, not any willingness to show itself. It stays active beneath the snowpack all winter, one of the busiest and least-seen animals in the state’s high forests.
Full species profile
