The least weasel is the smallest carnivore in North America, thin enough to chase mice straight down their own burrows, and that build makes it easy to miss even where it’s genuinely present. Montana has only 8 records of the species, half of them from iNaturalist, placing it in the bottom fifth for record counts among the state’s mammals.
The few sightings are scattered from February through April and September through November, too few to point to any real seasonal pattern. Charles M. Russell National Wildlife Refuge, the surrounding prairie wildlife management areas, and the Missouri River corridor all give the weasel the grassy, rodent-rich ground it needs to hunt. NatureServe still ranks it S4, apparently secure, in Montana, so the thin record count looks more like an under-surveyed species than a genuinely rare one.
Full species profile
