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 18 records of the species, all from GBIF specimen data with none from iNaturalist, placing it at the 9.5th percentile for record counts among the state’s mammals, one of the lowest in the group.
Sightings are spread thinly across nearly every month, with a small bump in July, but the numbers are too low and too even 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
