Several species of ground squirrels are abundant. At the lower levels, especially among creosotebushes, the ROUNDTAIL GROUND SQUIRREL finds suitable living conditions, while the YUMA ANTELOPE GROUND SQUIRREL ranges from the cactus forests into grassland. At this elevation and upward through the pinyons and junipers, the ROCK SQUIRREL makes its burrows in rocky ledges and brushy canyons. CLIFF CHIPMUNKS enliven the oak-pine woodland and higher forests with their quick movements and cheerful chatter. KANGAROO RATS honeycomb the soil from the cactus forests up to the oak-pine belt. Remaining underground during the day, they are frequently seen at night. These animals do not require free water; they obtain adequate moisture from a chemical process within the body during the digestion of food, which is mostly dry seeds. WOODRATS, famous in song and story as pack rats or trade rats because of their habit of carrying away objects of human use and leaving something else in their place, are found throughout the monument at all elevations. Look for their stick nests among the pads of prickly pear, a favorite food. Other rodents common in the monument include the CACTUS MOUSE, GRASSHOPPER MOUSE, DEER MOUSE, and VALLEY POCKET GOPHER. [Illustration: The four species of kangaroo rats found in Saguaro look too much alike to be distinguished in the field.] [Illustration: Mule deer.] Among the larger mammals in the monument are two species of deer. The MULE DEER subsists in winter on cactus fruits, ephemerals, and other desert vegetation. In summer they find abundant browse in the higher oak woodland. The forested areas along the crest of the Rincons support a population of the smaller WHITETAIL DEER. These graceful animals browse on aspen, buckbrush, and other shrubs and small trees. They are particularly fond of acorns. When snow flies some descend to the protective cover of the oak-pine woodlands and chaparral. PECCARIES, characteristic of southwestern deserts, usually travel in herds of from three to as many as 50 animals. They wander through the groves of mesquite along desert washes, and root among beds of pricklypear. Pricklypear pads are their chief food; they are said to feed upon cactus fruits in summer and autumn. In addition to the moisture obtained from succulent stems and fruits, peccaries require considerable water, hence they frequent springs and seeps. Small bands of these animals occasionally visit the waterhole near the visitor center, where they are excitedly watched by visitors fortunate enough to be in the lobby at the time. Saguaro National Monument also has a large number of predatory animals. Many of these, popularly believed to be exclusively meat-eaters, actually also eat much vegetable matter. The predators—an exciting part of the monument’s fauna—play an important role in preventing overpopulation of the prolific rodents.