Larger than a chipmunk, chestnut-gray on head and back. Distinguished from chipmunks by having black and white strips on its sides (none down the middle of the back) and by having a plain face with no stripping. Not as nervous and quick as the chipmunk. Total length 11 inches. Formerly called Say’s ground squirrel in this locality.
These trusting little fellows are the most commonly seen, photographed, and fed animals in the Park, (including the rangers). Dozens of these beautifully striped squirrels compete with chipmunks throughout the area for visitor “hand-outs” of peanuts. If left to themselves (those that haven’t forgotten how) they feed largely on plant material and seeds. There is a definite reason for this voracious engorging of food during the summer, which is enjoyed by the marmots and richardson ground squirrels as well. These animals are exemplary of the “true” hibernators of the animal kingdom. They go into burrows below frost line for a long winter period, curling up into tight little balls, and drop off into a death-like, torpid sleep from which they are aroused with some difficulty. Their temperature may drop from around ninety degrees F. to only forty; their heartbeat may reduce from approximately two hundred beats per minute to four or five; their oxygen consumption is less than ten per cent of the amount used in active condition. They utilize part of their stored-up summer fat for the little energy needed to keep alive. When the warm days of spring arrive, they dig their way out of the ground and search again for food and the customary “handouts.”
LEAST CHIPMUNK (Eutamias minimus operarius)
This little chipmunk is distinguished from the only other similar rodent in the Park, the golden-mantled ground squirrel, by its small size and nervous habit, stripes down the middle, as well as the sides of the back, and by narrow strips of black and white on its face. The tail is relatively long and bushy. Total length 8 inches. Found in Colorado east of the Continental Divide, from foothills to above timberline. Another least chipmunk (Eutamias minimus consobrinus) probably overlaps the range of operarius near the Continental Divide, and occupies the west half of the Park.
This quick nervous chipmunk is very common in all zones over 5,000 feet and is found scurrying among the rocks and along the forest floor, as well as running on tree trunks and branches. Like the ground squirrel, it has well-developed cheek pouches in which it can store an amazing amount of food. While it has a form of hibernation, it does not go into the deep torpor of the hibernating ground squirrel. It has been seen in the dead of winter running over the snows.
WESTERN CHIPMUNK (Eutamias quadrivittatus quadrivittatus)
A close relative of the least chipmunk of northwestern Colorado, which is rarely seen within the Park boundaries, and then not above 9,000 feet; is slightly larger and has a proportionately longer tail than the least chipmunk. Total length 8½-9½ inches.
NORTHERN POCKET GOPHER (Thomomys talpoides fossor)
A reddish-brown rodent with long, heavy, front digging claws. When compared to ground squirrels the pocket gopher has a heavier, chunky body and a shorter, thick tail. Has large, furlined cheek pouches. Total length 8½ inches. This group of pocket gophers is widely distributed from the great plains to the Pacific coast. Another subspecies (Thomomys talpoides clusius) occurs rarely in the Park although it is common in the plains and foothills. It resembles fossor except that its fur is brownish-gray.
Spending most of its life under the ground this well equipped excavator digs an amazing labyrinth of tunnels in western soils. It can make well over 200 feet of tunnel in a single night, usually digging down 5 or 6 feet below the surface. The prominent locator signs of the gopher are earthen mounds about 12 inches in diameter and 4 inches above ground level. In the center of the mound is an entrance to his tunnel system. In winter this tough, little rodent moves around above ground under the snow. His digging continues at this time and the excavated earth is pushed out of the ground and into his snow tunnels. When the snow melts the next spring the long, irregular earth cylinders lying on the ground are exposed. This shy, secretive gopher is difficult to see even at his earthen look-out mound, because he rarely exposes himself when intruders are nearby. They are found occasionally in meadows up to timberline.