Part 6

Squirrels play a considerable part in perpetuating this national heritage. The fact that they do this more or less accidentally merely serves to call attention to the subtle patterns in which all living things move to serve one another. Take their simple mechanics of storing a pine cone, for instance. A hole is dug to a depth of several inches in the soft duff under a shady conifer. The cone is pushed firmly into the bottom of the hole and tamped into place with several vigorous shoves of the nose. Then the hole is carefully filled and smoothed over so that no marauder will discover it. This procedure may be repeated hundreds of times by one individual. If the animal never returns (and the rate of mortality among squirrels is high), the cone can be considered planted. Not only is it planted at the correct depth and in the most suitable material for successful germination and growth, but it is full of plump fertile seeds. Through some instinct the squirrel knows which nuts and cones are healthy and fully developed. If you doubt this, examine some of those they have left on the tree. Invariably they will be infested by insects or “inferior” in some other respect. One of the favorite sources of pine nuts for reforestation projects in the Northern States is the stockpiles of the red squirrel. The scales of the cones are tightly closed when they are taken, but as they open on the drying floor the healthy, fertile nuts prove the unerring judgment of the harvester.

Northern flying squirrel _Glaucomys sabrinus_ (Greek: glauco, silvery and Greek: mys, mouse)

Range: Widely distributed throughout most of our Northern States and Canada. In the section covered by this book, found only in northeastern and south central Utah, with possible occurrence in northwestern Colorado.

Habitat: Associated with conifer forests of Transition to Alpine Life Zones.

Description: Our only airborne mammal with a long bushy tail. Total length 9¾ to 11½ inches. Tail 4½ to 5½ inches. Characteristic of this species is the fold of skin along each side from the fore to the hind leg. There is considerable color variation in the numerous subspecies of this squirrel. In general the upper parts vary from dark brown to cinnamon brown. Sides of face gray; underparts white to pinkish cinnamon beneath. Hind feet are brown, fore feet gray. The flying membrane is brownish black above, white to cinnamon beneath. The eyes are large and dark brown. Young, two to six in a litter, born in spring; a second litter is sometimes produced in early autumn.

Because flying squirrels are almost entirely nocturnal, they are seldom seen. This is unfortunate, for they are among the most interesting forest creatures. Probably more people have seen flying squirrels through the predations of a house cat than in any other way. Gentle and unafraid, the squirrels fall easy prey to this night prowler, which sometimes brings them home to show its owners. Strangely enough, the victims often are not injured seriously, and if taken from the cat and allowed to recover from their initial fright they will glide about the room with much of the grace they display in the wild.

Properly speaking, these squirrels do not fly; that is to say, they are incapable of sustaining level or ascending flight. Rather they climb to some height in a tree then launch out and glide to a lower point, usually the trunk of another tree. As the angle is usually quite sharp they attain considerable speed. They check this momentum by inclining upwards just before reaching their objective. This results in a four-point landing against the tree trunk, sometimes with an impact that can be heard for some little distance on a quiet night. During these flights, which may extend 50 yards or more, they are able to change direction or maneuver against wind currents. This is done by manipulating the flying membrane and using the tail as a rudder. After a flight they usually ascend to the safety of the foliage above. They cannot be considered awkward on the ground, but it is not their chosen habitat. Flying squirrels are more arboreal than any of our mammals, excepting a few species of bats.

Little is known of the habits of this unusual squirrel, but they differ considerably from those of its relatives who are active during the sunny hours. Instead of living in a bulky nest hung in tree branches, this nocturnal aerialist chooses a hollow tree or an abandoned woodpecker’s hole where the sun’s rays never penetrate. Nests have been found also under slabs of bark hanging to old lightning-blasted snags. Lined with soft fibers and shredded bark, they often shelter whole families of flying squirrels for, unlike the other squirrels, these gentle creatures get along together. In fact, they might almost be considered gregarious. Contrary to ordinary squirrel behavior, they never bark or scold. Their only utterance is a fine whistling squeak, and this is heard usually only in the nest.

Though delicate in appearance the flying squirrel is extremely hardy. It is abroad throughout the winter, being confined to its nest only during stormy weather. It stores food for the winter, but its caches are usually above ground in hollow trees and crevices rather than buried in the loam. Their food consists mostly of pine nuts, seeds, and acorns, but they are also fond of meat. Many a flying squirrel has met its death trying to take the bait from a trap set for larger game. This taste is unexplained; it is not known to prey on other animals.

Western chipmunks Genus _Eutamias_ (Greek: eu, well or good and tamias, steward)

There are at least four species of chipmunks native to the area covered by this book. Ordinarily but one, or perhaps two, species of a genus have been chosen for discussion. In this case, however, the chipmunks are such provocative little creatures and their presence causes so much interest that all four species will be included, although briefly. Since the ranges and life zones of some of them overlap in many areas, positive identification of a species will be difficult in those places, but in others one species will be dominant or alone. Here the more subtle characteristics and behavior of that type can be fixed in mind, and in time it will be less difficult to separate one from the other. Remember that most of these species have several subspecies. These generally occur along the upper or lower edges of the life zone frequented by the type. In the field they are usually indistinguishable from the type to any but the most practiced observer.

1. Colorado chipmunk (_Eutamias quadrivittatus_)

Range: Northern Arizona, northern New Mexico, most of Utah, and all but the most northern portion of Colorado. This chipmunk lives largely in the Transition Life Zone. The closely related species _umbrinus_, commonly called “Uinta chipmunk” inhabits the Canadian and Hudsonian Life Zones in the Uinta and Wasatch Mountains of northeastern Utah.

2. Gray-necked chipmunk (_Eutamias cinereicollis_)

Range: Central Arizona eastward into southwestern and south central New Mexico. Total length 7½ to 10 inches. Tail 3½ to 4½ inches. Transition Life Zone and above. _Neck and shoulders gray._

3. Least chipmunk (_Eutamias minimus_)

Range: Western Colorado, western Utah, northern and eastern Arizona, northern and central New Mexico. Inhabits all zones from Upper Sonoran to Alpine. Total length 6⅔ to 9 inches. Tail 3 to 4½ inches. _The smallest chipmunk with proportionally the longest tail. Tail carried straight up when running._

4. Cliff chipmunk (_Eutamias dorsalis_)

Range: North and western Utah extending through southeastern Arizona and western New Mexico. Found mainly in the Upper Sonoran Zone. Total length 8⅘ to 9½ inches. Tail 3⅘ to 4½ inches. _The most indistinctly striped of any of these chipmunks._

Generally speaking, chipmunks are the link between ground squirrels and tree squirrels. Physically they have characteristics of both groups, a combination that is pleasing indeed. A field mark that is a positive identification of the chipmunk group is the striped face. In addition to facial stripes, chipmunks also are striped along the back. The pattern consists of a dark to black median line bordered by two more similar lines of varying intensity along each side. These fine lines are separated by broader bands of contrasting color ranging from chestnut to white. The latter characteristic is shared by several of the ground squirrels, which often are confused with chipmunks. Predominant colors of southwestern chipmunks run to rufous, chestnut, and grayish white with the dark to black lines mentioned above. Underparts are always considerably lighter than the back. Chipmunks’ tails are usually shorter than their bodies, flattened horizontally, and short haired when compared with tree squirrels. All species have cheek pouches of considerable capacity.

As will be seen from ranges given above, habitat of the chipmunks encompasses the whole area from sagebrush-covered foothills to timberline. Their densest population, however, is to be found in thick forest about midway between these two extremes. Here their bright colors and sprightly actions do much to enliven somber surroundings. Despite their wonderful climbing ability, they are most often seen at ground level or just a little higher. They are fond of areas containing fallen trees. The prostrate trunks serve admirably as highways for their forays in search of food, and under the litter which accumulates around them are many havens into which a hard pressed chipmunk may pop when pursued by an enemy. The territory appropriated by each of these little creatures is explored with the most minute care, and all places of refuge are noted for future emergencies. Any attempt to chase them will reveal their uncanny memory for these temporary hiding places and that they are seldom at any great distance from one.

Their permanent homes usually are underground, excavated beneath the roots of trees or in rocky terrain. At the end of a narrow tunnel a room of considerable size is worked out. The dirt is often carried out by a side tunnel, which is permanently plugged with soil when the excavation is completed. The underground chamber is lined with soft grasses and fibers as insulation against the cold. At the higher elevations the ground may freeze to a depth of several feet during the long winters. Permanent nests are sometimes built in hollow logs, but almost never in holes in upright trees. Chipmunks have little taste for upstairs apartments. In addition to the large cavity which contains the nest, several storage chambers are constructed to hold the winter’s food. These may be connected to the main apartment by tunnels or may be entirely independent of living quarters and some distance away. As a special feature, many of the more elaborate homes have a separate chamber reserved for sanitary purposes. Like most of our native rodents, chipmunks are fastidiously clean in their habits.

It is difficult to discuss the habits of a group as large and of such wide distribution as our southwestern chipmunks in any but a most superficial manner. In general they are much more terrestrial than squirrels and prefer brushy, rock terrain to the more open forests frequented by their larger relatives. Nevertheless, they are adept climbers and do not hesitate to take to the trees in search of food or to escape their enemies. These arboreal excursions are usually limited to one tree; they do not ordinarily attempt the daring leaps from one to another that are characteristic of the squirrels. They progress quietly while on the ground, threading their way through the undergrowth so expertly that their presence is often undetected.

Normally chipmunks are shy creatures at first acquaintance, but if their friendship is encouraged they often become bold to the point of being unwelcome. Woe to the camper whose grub box is invaded during his absence. These tiny opportunists can carry away a surprising amount of food in a very short while. Their natural diet differs widely according to habitat. Chipmunks of the foothills eat a great variety of grass seeds, berries, and cactus fruits. These are possibly the favorite foods of the whole group, but as the elevation increases this supply becomes limited and is supplemented by juniper berries, acorns, and pine nuts. Considerable quantities of these less perishable foods are laid away for future needs. During the summer months herbage, fungi, small tubers, and some insects add variety to an otherwise dry menu.

It is doubtful if any southwestern chipmunks enter true hibernation during the winter. Those of lower elevations are active throughout the colder months, except when a period of exceptionally inclement weather will force them to remain underground for a few days. At higher elevations they will disappear, perhaps for weeks at a time, but it is assumed they remain active in their underground quarters. The fact that during the fall they do not lay on a coat of fat, like many species which are known to hibernate, substantiates this theory.

Breeding habits of chipmunks are not too well known. The number of young averages from four to six. Those species living at low elevation sometimes bear two litters each year; those at higher elevations are limited to one. Like the ground squirrels, the young are able to leave the burrow when but little more than half grown. At this early age they present a rather ludicrous appearance with their large heads and sparsely-haired tails. This is a time of great danger, for the youngsters are easily caught by predators which would be eluded with little difficulty by a mature individual. Principal predators of the chipmunks are bobcats, hawks, foxes, and coyotes. The last two often dig out the burrows. The marten is possibly their worst enemy, but fortunately for the chipmunk tribe is a rare animal throughout its range.

Chipmunks are quite common in several of our southwestern National Parks and Monuments. Despite signs to the contrary, the public cannot resist feeding these little beggars, and many are the situations that develop from this practice. I recall camping at Bryce Canyon National Park where the least chipmunk is a common resident. Upon our return from Rainbow Point one day we spied a chipmunk with bulging cheek pouches leaving our tent for its den somewhere on the edge of the canyon rim. We found that our visitor had entered the grub box and gnawed a neat hole in the top of a carton of rice. Although we had been gone but a short time, more than half the contents had already been carried away. This was a state of affairs that needed mending so we decided to teach the marauder a lesson. On his return trip we waited until he had entered the carton and then clapped a dishtowel over the hole. The cellophane window in the side of the carton gave us an excellent view of our prisoner. Interrupted in his pilfering, he at first tried to get out of the carton but, finding no exit, returned to stuffing his cheek pouches with more rice. When they were filled to capacity he calmly sat back and returned stare for stare. In the end we let him go and gave him the rest of the rice, exacting such payment as we could by taking pictures of his labors.

Golden-mantled ground squirrel _Citellus lateralis_ (Latin: citellus, swift, and lateralis, belonging to the side, referring to the stripe along the side)

Range: Western United States and Canada. In the area covered by this book to be found in western Colorado, from northeastern Utah south through central Utah to central Arizona thence east into western New Mexico.

Habitat: Higher mountains of this area. Usually found in evergreen forests of the Transition, Hudsonian, and Canadian Life Zones. It sometimes occurs near the upper limits of the Upper Sonoran Zone.

Description: A chipmunk-like ground squirrel lacking the stripes along the sides of the face characteristic of the chipmunks. Total length 8½ to 12½ inches. Tail 2½ to 4½ inches. There is much color variation in this species. Head coppery to chestnut, upper surfaces of body brownish gray to buffy. A light to white stripe bordered with black is present on each side of the back. Under surface of tail gray to yellow. Tail short but fully haired. Under surfaces of body lighter, gray to buffy gray. Legs short, body chunky in comparison with chipmunks. Young, four to eight, with but one litter each year.

The golden-mantled ground squirrel has been chosen from the rather large group of southwestern ground squirrels because it is most typically a mountain dwelling species. As such it does not have the advantages of a long summer season like its lowland relatives. This results in two definite periods each year. One is feverish activity during summer, a time of breeding, rearing the young, storing food, and laying on fat for the cold months ahead. The other in winter is the exact opposite—a long interval of hibernation when, buried deep under the snow in a snug burrow, the squirrels sleep away the winter.

Though hampered by the short summers of higher elevations, the golden-mantled ground squirrels manage to lengthen the season slightly by a very simple expedient. Instinct prompts them to dig their burrows on a southern exposure, often under the base of a log or in a rock slide. Here the snow melts away first and they often have a bare spot of ground in front of the burrow several weeks in advance of the season. The squirrels emerge from their long sleep weak and emaciated, and their first days above ground are spent soaking up the warm sunshine and waking up, so to speak. During this period they live on stores laid away the previous summer, and by the time the snow has melted they are fully active and ready for mating.

As with the ground squirrels of lower areas, the summer diet consists largely of whatever starts to grow first. During late spring, grass, buds, young leaves, and flowers are eaten. Later, seeds of the annuals are gathered, berries are taken whenever possible, and insects often form a considerable part of the diet. As fall comes on, acorns, pine nuts, and a great number of smaller seeds and fruits become available. At this time the ground squirrels must not only lay on enough fat to maintain themselves through hibernation, but must also store away enough food to tide them over between the time of their emergence and the appearance of new growth. Evidently this is an adaptation forced upon them by the exceptionally long winter season. Most rodents which lay on coats of fat preparatory to hibernation depend almost entirely on it to carry them through. With a hibernating period of from 5 to 7 months, however, it is not difficult to realize the problems this ground squirrel must face.

Though the golden-mantled ground squirrel resembles the chipmunks in appearance, its temperament is quite different. Chipmunks are bright, nervous little sprites, always pursuing their activities with explosive energy. The ground squirrels move more sedately, as though they had planned every move and there was no hurry. They love to lie in the sun in some exposed place and watch the rest of the world go by. In habitat, too, the species differ materially. Chipmunks choose thick undergrowth where they can go about their business unobserved. Ground squirrels prefer more exposed locations where they take their chances in the open, but with one eye always cocked aloft as insurance against attack by hawk or eagle. Creatures of the earth, they are always reluctant to climb. Rarely do they ascend more than a few feet, and then only to reach some especially toothsome delicacy that their keen noses have detected in a low shrub or small tree.

With its wide distribution, visitors to the southwestern mountains can hardly fail to notice this golden-headed member of the ground squirrel family. It is easily tamed; too easily in fact for, like the chipmunk, it can quickly wear out its welcome. In many of the National Parks and Monuments they compete with chipmunks for the crumbs around camp sites and picnic tables. Visitors find their cunning way irresistible and feed them despite warnings to the contrary. Because they do tame so easily there is always danger that some well-meaning person will attempt to pick them up. This can lead to unpleasant results. Their long sharp incisors can inflict a serious wound.

One of the most fascinating places to observe both chipmunks and these ground squirrels is from the windows of the long tunnel leading northward out of Zion National Park. On the talus slopes beneath the windows a great number of these rodents take up summer quarters, depending for food on the largesse distributed by visitors as they eat their picnic lunches on the broad ledges of the windows. Their constant movements as they run among the rocks seeking stray crumbs result in many a collision and often an angry dispute as well. This proves a dangerous game, as rocks sometimes will be loosened by their movements and roll down the steep incline. I recall seeing a ground squirrel crushed by one of these miniature rock slides in 1946.

White-tailed prairie dog _Cynomys gunnisoni_ (Greek: kun, a dog and mys, mouse ... for Captain Gunnison whose expedition took the type)

Range: Western Colorado and eastern Utah to central Arizona and New Mexico.

Habitat: Grassy meadows and mountain parks mainly in the Transition Life Zone although they are often found both above and below this area.

Description: A ground-dwelling rodent somewhat resembling a ground squirrel but several times larger than the biggest species of that genus. Total length 12½ to 15 inches. Tail 2¼ to 2½ inches. Weight 1½ to 2½ pounds. Color buff to cinnamon buff, the short fully-haired tail tipped with white. Sides of face darker with a dark area over the eyes. Legs, feet, and underparts pale cinnamon buff. Young, usually five in number, born in early summer.

_Cynomys gunnisoni_ is the representative species of the western group of prairie dogs. The two remaining of the group, _Cynomys leucurus_ and _Cynomys parvidens_, both white-tailed species, are very similar and possibly will be classified with _Cynomys gunnisoni_ in the future. _Cynomys leucurus_ is found in northwestern Colorado and northeastern Utah, while _Cynomys parvidens_ is native to mountainous valleys in central Utah.