California holds 374 open records for the mountain beaver, the southern tail of a range that runs the length of the cool, wet Pacific coast from British Columbia down through Washington and Oregon.
A coastal specialist with outposts, not one continuous range
California’s mountain beavers aren’t spread evenly across the state. The core here sits in the redwood and Douglas-fir country of the Klamath Mountains and North Coast Ranges, Del Norte, Humboldt, and Trinity counties, connected north into Oregon’s much larger range. Point Reyes National Seashore, listed on this page, is a genuine match: Marin County holds one of the species’ isolated southern outposts, cut off from the main coastal range by drier country in between. Channel Islands National Park isn’t a match at all. Those islands are far too dry and lack the damp forest cover a mountain beaver needs to survive.
Neither a beaver nor a mountain specialist
Despite the name, this animal doesn’t build dams or carry a paddle-shaped tail, and it’s not tied to high elevation either. It’s the only living member of an ancient rodent family, a stocky, short-tailed burrower that needs cool, damp ground more than altitude. Leaves, ferns, and bark make up its whole diet, cut and hauled into or near its tunnel system, and because it doesn’t hibernate, that damp shelter has to hold up through every season, not just winter.
Status in California
NatureServe hasn’t assigned the mountain beaver a numeric rank in California, and it’s treated as native across its mapped coastal range here. June through August together account for well over half the state’s records, a pattern that more likely tracks when field crews and hikers are out looking than any real seasonal shift in an animal that stays active, and hidden, all year.
Full species profile
