Most other recent authorities, including those named above, have recognized the involved phenomena as limited hybridization between full species.
Males are considerably larger than females.
The short, soft, smooth fur is not sharply bicolored, for the underparts are only slightly paler than the upper parts. The color varies from almost black through gray and brown to almost white. Western pocket gophers have a robust body, short legs, small eyes and ears, and long front claws. The slightly tapered, thinly haired tail is naked at the tip. Unlike in most other geomyids, the incisors of Thomomys usually lack frontal grooves.