Golden Pocket Gopher 79 
Thomomys aureus (Lat., golden). Golden Pocket Gopher 
Thomomys aureus, Allen, Bull. Am. Mus. N. H., v., p. 249 (1893), 
Type locality.— Bluff City, San Juan Co., Utah (C. P. Rowley). 
Measurements. — Total length, 9.7; tail vert., 2.5; hind foot, 1.35. 
Description. — (From a specimen taken in western Montezuma 
County April 13th): Above a bright light golden brown ; a little 
blackish on face; feet and under parts whitish gray, tinged a little 
with buffy. Tail buff y above, paler below. There is considerable 
individual variation in color, and some specimens are much darker 
than this. 
This species has proportionately the largest and most massive 
skull of all the Colorado Thomomys; the zygomatic arch is wide- 
spreading and squarish with flattened and flaring malar ; the brain 
case wide posteriorly, and the interorbital constriction considerable. 
The nasals do not extend as far back as the ends of the maxillae. 
Specimens from southwestern Montrose County (Coventry and 
Bedrock) are dusky brown above, with blackish appearance on 
back; muzzle and chin blackish, under parts pale fulvous. A 
rather differently colored animal from typical aureus, but skulls 
identical. 
The variation in color described in Montrose County specimens 
is similar to that noted in the case of the Moki Kangaroo Rat and 
the Apache Pocket Mouse. It is a darkening and dulHng of the color 
of the upper parts, possibly having some connection with the color 
of the soil, which in this region is a reddish color, evidently due to 
iron oxide. It is a curious fact that this has apparently affected 
these three species only, and that they all are burrowing animals 
having external cheek pouches. 
Distribution. — The Golden Pocket Gopher has been reported 
from Utah and Colorado, and no doubt occurs in the adjoining parts 
of New Mexico and Arizona. In Colorado it has been taken in 
La Plata, Montezuma, Montrose, and Mesa counties, up to about 
7,000 feet altitude, or perhaps somewhat higher, where it would 
begin to overlap the range of Thomomys fossor. 
Habits. — Nursing females and half-grown young have 
been taken in April, and in the same month a specimen was 
taken containing four embryos. 
Thomomys aureus pervagus (Lat. per, through, + vagusy 
wandering). Roaming Pocket Gopher. 
Thomomys aureus pervagus Merriam, Proe. Biol. Soc. Wash., 
xiv., p. 1 10 (1901). 
