by Inger Giuffrida, executive director, WildCare Oklahoma
Squirrels are one of the most prolific mammals on earth, with 278 species worldwide. They are members of the order Rodentia, commonly called rodents as a group. In addition to mice and rats, this diverse taxonomic order includes hamsters, guinea pigs, gerbils, prairie dogs, woodchucks, beavers, porcupines, capybaras, and others.
Rodents are differentiated from other species by their front teeth — the incisors do not stop growing, and they are harder than lead, copper, and iron. The animals keep them trimmed and sharp by gnawing them together and chewing on nuts, wood, and other tough material for food or building their nests and homes.
The Squirrels of Oklahoma
Squirrels belong to a family called Sciuridae and are further categorized as tree squirrels, flying squirrels, and ground squirrels. In Oklahoma, you can find all three types. Eastern fox and eastern gray squirrels are the two species of tree squirrels. The southern flying squirrel is the only species of flying squirrel. Thirteen-lined ground squirrels, spotted ground squirrels, eastern chipmunks, and the black-tailed prairie dog are classified as ground squirrels.
Tree Squirrels
Tree squirrels are so named because of their arboreal nature. Unlike their ground-dwelling cousins who live in burrows and dens, tree squirrels make their nests among the branches and hollows of trees.
Fox squirrels and gray squirrels have similar habitats, ranges, and diets. Both live best among hickory, maple, oak, walnut, pecan, Osage orange, Kentucky coffee, and pine trees. Most of their diet consists of nuts produced by trees in their habitat but also includes tree buds, tubers, seeds, insects, bird eggs, bulbs, and roots. The tree squirrels’ diet varies depending on the types of trees and shrubs where they live.
Eastern Fox and Eastern Gray Squirrels
Eastern fox squirrels are larger than gray squirrels and have reddish brown fur with yellowish bellies. Eastern gray squirrels have white bellies. Eastern gray squirrels, however, can be brown (brown morph), white (leucistic), or black (melanistic).
Both fox and gray squirrels have bushy tails which they use for balance while running along narrow branches, as a rudder to correct their course when jumping, and in communication. Have you ever noticed a squirrel chattering and flicking his tail? That flicking is a sign that the squirrel is upset about something or someone.
Squirrels Are Great Mothers
Eastern fox and gray squirrels are excellent parents. Mother squirrels tend to their litter of as many as four young for about three months, after which their offspring live independently from their mother. If young squirrels are orphaned, their grandmother or aunt might take them in to raise with their own brood.
When given a chance, mother squirrels will often retrieve babies that have fallen from their nests. The WildCare Oklahoma staff coaches hundreds of people a year on ways to facilitate reunification. This generally involves placing the baby in a shallow box with a soft cloth on the bottom to keep the baby comfortable, playing the recording of a baby squirrel crying for its mother on a mobile phone at full volume next to the box, clearing the area of people and pets, and forgoing yard work.
People are shocked and overjoyed when they see the mother scamper down the tree, grab the baby by the scruff of the neck, and carry it back to the safety of the nest.
Caching Food
Fox and gray squirrels always seem busy because they are constantly caching food throughout their territory for the months when food is unavailable. They relocate most of it through smell and spatial mental mapping. If they forget about a cache, it often develops into a sapling tree, thus contributing to their preferred forest habitat.
Tree squirrels are known to dig fake holes to fool onlookers and throw off thieves — a move known as “deceptive caching.” This involves a squirrel digging a hole and covering it up again but not depositing a nut.
Southern Flying Squirrels
Southern flying squirrels would be more aptly named gliding squirrels. A membrane of skin, called a patagium, from the wrists of the front paws to the ankles of the back legs allows them to glide in the forests they inhabit. The tail acts as the rudder, allowing them to adjust their direction.
Like their cousins, flying squirrels cache food during summer, usually in tree cavities but also in the ground. Unlike eastern fox and gray squirrels, flying squirrels do not remain active all winter. Instead of hibernating, they go through a process called torpor when temperatures drop and resources are scarce. Their metabolic rate drops, and they are inactive. This is considered an involuntary response to environmental conditions that allows these small squirrels to conserve energy. Torpor can last from hours to weeks and makes the animals vulnerable to predation.
Flying squirrels live in close-knit family groups with many families living together in colonies. They are extremely social animals, a key consideration for releasing southern flying squirrels cared for at WildCare Oklahoma. Rehabilitated patients must be released into a known, established colony, ideally the one where they originated.
Southern flying squirrels have two litters each year consisting of two to seven young.
Beware of Cat Attacks
The most common reason southern flying squirrels are brought to WildCare Oklahoma is cat attack. (It’s also the second most common reason for admission of eastern fox and gray squirrels.) Cats should always be kept indoors because they are an invasive species in natural environments and one of the top reasons for wildlife death and injury in the United States.
When attacked by a cat, southern flying squirrels and any wildlife must be taken to a wildlife rehabilitation center for care. Because of their complex social structures and interdependence, they are challenging animals for wildlife rehabilitation centers.
Ground Squirrels
Ground squirrels are a diverse group. When compared with their tree and flying cousins, ground squirrels are larger, have fur color that allows them to be camouflaged, and live in burrows that they dig. Thirteen-lined ground squirrels and many other types hibernate.
Squirrels Play a Role in the Food Web
Squirrels are an important food source for many nonhuman predators, such as snakes, coyotes, bobcats, raccoons, red and gray foxes, and birds of prey, including eagles, hawks, owls, and some falcon species. People have long hunted squirrels too.
In addition to being a source of nutrition and sustenance for a wide range of wildlife species, squirrels are also known as nature’s gardeners. Nuts and seeds that they cache but don’t eat can sprout to become trees that provide habitat, safety, and food for generations of wildlife. The trees enhance the environment for humans too, improving the quality of the air we breathe and cooling our built environments.
It is often stated, “The best time to plant a tree was 20 years ago.” The second-best time is now. The next time you see squirrels busy in your yard caching nuts, remember that they are planting trees now and think of all the good they do for the flora and fauna of Oklahoma, including humans.
If you find an injured, orphaned, or ill squirrel or any other wildlife species, please contact the WildCare Oklahoma help desk at (405) 872-9338. The desk is staffed 365 days a year, including holidays.
