North Dakota’s occurrence data holds 85 beaver records, most of them iNaturalist sightings rather than museum specimens. For an animal that reshapes its own habitat, that’s a small number, but it reflects how much of its work happens underwater and after dark.
Dam builders in an otherwise dry landscape
Beavers turn up along the state’s major drainages: the cottonwood-and-willow river bottoms of the Little Missouri through the Little Missouri National Grassland, the backwaters and coves of Lake Sakakawea on the Missouri River, and the Souris River wetlands at J. Clark Salyer National Wildlife Refuge, prime slow-water habitat for a dam-building rodent. In the Badlands especially, a beaver dam on a side drainage can be the most reliable water source for miles, a resource plenty of other wildlife rely on too.
Records cluster around ice-out
Reports run heaviest from May through July, tapering off by late fall. That timing lines up with beavers becoming easier to spot once spring runoff clears the Missouri and Little Missouri and animals get busy repairing winter-damaged dams and lodges, not with any real shift in how much they’re working the water. By late fall, beavers are hauling in a winter food cache of branches to store near the lodge, working mostly at night and under ice once the cold sets in, which naturally means fewer people see them.
Status in North Dakota
NatureServe ranks the beaver S5, secure, in North Dakota, and it’s native throughout its North Dakota range. Its dam-building keeps it a fixture of the state’s rivers even where the surrounding country is otherwise short on standing water.
Full species profile
