Pocket gophers occur only in North and Central America but within this vast area few other native rodent groups are more widely distributed (Anthony, 1928). None are more adaptable, either to natural extremes of habitat or to changed conditions brought about by agricultural development and other man-made environmental modifications. They occupy coastal areas, inland plains and valleys, desert and alpine meadow, from sea level to above timber line in a multitude of vegetation and soil types. This practically universal distribution has, of course, led to the recognition by naturalists of many species and subspecies. California alone contains at least 75 species and subspecies all within the one genus Thomomys — the western pocket gopher — whi...