The North American least shrew is barely bigger than a large insect, one of the smallest mammals in the country. Unusually for a shrew, it shares nests and huddles with others through cold weather instead of living alone. Illinois sits near the northern edge of its mostly southern and Plains range, with records concentrated around Shawnee National Forest, Crab Orchard National Wildlife Refuge, and Cache River State Natural Area in the state’s far south.
Only 62 records turn up statewide, enough to land this species in Illinois’s ‘rare’ bucket, yet NatureServe still ranks it S5, Secure, here, a reminder that a thin record count often just reflects how easily this shrew hides in dense grass, not a real population problem. Reports climb sharply in November and December, which lines up with the species elsewhere: young shrews disperse and turn up in new spots that time of year, not necessarily because more are active then.
Because it’s tiny, mostly nocturnal, and rarely ventures into the open, most Illinois sightings probably come from a shrew stumbling into view, not anyone tracking it down.
Full species profile
