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| Telltale signs of a Rock Squirrel Den |
The squirrel family includes several different species that are grouped into tree squirrels, ground squirrels, and flying squirrels. In central Texas, most are familiar with the Eastern Fox Squirrel (Sciurus niger) and the Eastern Gray Squirrel (Sciurus carolinensis), both of which are tree squirrels, meaning their habit is to live mostly among trees. The Southern Flying Squirrel (Glaucomys volans) occurs rarely in the eastern most portion of our area, and is named for the special flaps of skin on the sides of its body which allows for gliding flight. But it is the Rock Squirrel (Spermophilus variegatus), which generally lives on or in the ground rather than in trees, that is our most notable ground squirrel.
Rock squirrels are stout, moderately bushy-tailed mammals, with mottled grayish-brown upperparts, a more brownish hind back and rump, buffy underparts, and a tail mixed with buff and brown and whitish tips. The head and upper back are often distinctively blackish, and they have a light-colored ring around each eye. Adults are typically about 18 to 20 inches long, including the tail, and are found from central Texas westward into the Trans-Pecos region of west Texas.
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| Adult Rock Squirrel |
As their common name implies, rock squirrels nearly always inhabit rocky areas such as cliffs, canyon walls, cervices, and rock piles, and even man-made areas like fills along highways and retaining walls. These areas are where they seek refuge and create their dens. Although they are typical ground squirrels, they can climb trees nearly as well as tree squirrels, where they can forage for berries and seeds, and they can scale rock walls with ease. Their diet consists of a variety of plant materials, along with many types of insects. Unlike many other squirrels, they are fond of flesh and can catch and eat small birds. They can survive long periods without water, some even up to 100 days.
Rock squirrels are facultative hibernators meaning they enter hibernation only when either cold-stressed, food-deprived, or both. In central Texas they generally hibernate from November to February or March, often coming out to sun during warmer winter days. Their populations tend to be colonial, each consisting of multiple breeding females and a dominant male. Home ranges can be fairly large and include several different dens, and the males are thought to be polygamous. Breeding occurs in March and April with an average litter of 4 young that emerge from the den in late spring.
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| A litter of 5 young Rock Squirrels |
Most active in early morning and late afternoon, rock squirrels are rather shy and difficult to observe at close range. Like other ground squirrels, they are known for their tendency to rise up on their hind legs whenever they need to see over tall vegetation or when they sense nearby danger. They then curl their front paws flat against their chests and send out a sharp, clear whistle to warn other family members if they sense the presence of predators. Now you know more about Texas’ very own real-life version of Rocky the Squirrel!
