Rock squirrels (Otospermophilus variegatus) are ground squirrels found across the southwestern United States and Mexico. They are common in rocky landscapes, playing a role in seed dispersal and serving as a food source for various predators. Their characteristics, behaviors, and survival strategies highlight their ecological significance in arid and semi-arid environments.
Identifying a Rock Squirrel
Rock squirrels are large, heavy-bodied ground squirrels, measuring between 17 and 21 inches in length, including their tail. Their tails are long and bushy, often nearly half the length of their body, and feature white edges. Their fur is mottled grayish-brown on the upper parts, often with a brownish-black or buff white underside. Some individuals may also have indistinct wavy markings or patches of cinnamon brown. A light-colored ring around their eyes is a distinguishing feature, and they have large heads with pointed ears.
Where Rock Squirrels Live and How They Behave
Rock squirrels inhabit a wide geographic range across the southwestern United States and Mexico. Their preferred habitat includes rocky areas such as cliffs, canyon walls, talus slopes, and boulder piles. They can also be found in urban and suburban environments, often burrowing under human-made structures or along irrigation ditches.
These squirrels are diurnal, active during the day, with peak activity in the early morning and late afternoon to avoid extreme heat. They are skilled burrowers, creating extensive underground tunnel systems for shelter, living space, and food storage. Social structures vary; in denser areas, they form colonies often consisting of several females and a dominant male. While primarily ground squirrels, they are capable climbers, often seen scaling trees or perching on rocks as lookout points.
What Rock Squirrels Eat and How They Survive
Rock squirrels are omnivorous, with their diet adapting to seasonal availability. They consume a wide variety of plant matter, including seeds, nuts, berries, fruits, leaves, roots, and flowers. Specific plant foods include acorns, juniper berries, and various grasses and cacti. They also eat invertebrates like grasshoppers and beetles, and occasionally small vertebrates or carrion. They use cheek pouches to gather food, carrying it back to burrows to consume or cache for later use, especially for winter.
Rock squirrels thrive in arid and rocky environments due to several adaptations. They can endure long periods without direct water, obtaining hydration from dew, succulent vegetation, and bulbs. To manage body temperature, they are most active during cooler parts of the day and may estivate during very hot periods. In colder months, they may enter torpor or hibernation, though in southern areas, they often remain active year-round.