That North American beaver ("Castor canadensis") were once native to the Walker River is evidenced by a 1906 article in the Nevada State Journal newspaper by newspaper mining writer Fitz-James MacCarthy (aka Fitz-Mac) stated that the Mason's Valley of the Walker River in Yerington, Nevada was well known to "the early trappers and fur hunters...Kit Carson knew it to the bone...The beavers of course were all trapped long ago, and you never see an elk nowadays..." Beaver have since re-colonized the Walker River watershed.