The mountain type of this, seen here, is the most primitive living rodent
A certain type of flea is 
found only on mountain beavers and would have no interest ... most of the states 
and all Canadian provinces but are seldom seen because they do... [DOC] [TLE] The Pacific Northwest's elusive mountain beaver | The Seattle Times [PAR] Feb 8, 2009 ... ... known as the mountain beaver, is the world's most primitive rodent: elusive, 
destructive and often mean.