Our Notable Squirrels
By Nikki Dahlin, Naturalist
Community Services & Education
We’re celebrating the friendly squirrel on “Squirrel Appreciation Day” — one of the lesser-known holidays — on Jan. 21 from 10 a.m. – 2 p.m. at Willowbrook Wildlife Center in Glen Ellyn. Join us to learn about these acrobatic rodents with lots of “nutty” squirrel-related activities.
A variety of members from the Sciuridae family live in DuPage County’s forest preserves, including the eastern chipmunk, 13-lined ground squirrel, woodchuck, eastern gray squirrel, fox squirrel — and even the flying squirrel!
We’ve gathered a few fun facts to help you appreciate these appealing, industrious animals not only on this special day but every day.
The eastern chipmunk lives in an underground burrow that can extend from 10 – 30 feet! During the winter, this squirrel enters a state of torpor but does not hibernate. Its survival depends on a stash of nuts and seeds gathered from mid-summer to fall. It’s not unusual for this industrious little creature to gather 150 acorns in one day, a survival stockpile it must defend against other marauding chipmunks. Chipmunks make their den entrance less visible to predators by tunneling under rocks (or patios!) and carrying the excavated dirt away. Although they may not have the musical talents of “Alvin and the Chipmunks,” they do have a variety of calls and are known to “sing” together.
The 13-lined ground squirrel is sometimes confused with a chipmunks but is easy to distinguish by its 13 lines: seven dark stripes separated by six lighter stripes along its back. It prefers to live in prairies and grasslands. These squirrels welcome one another by touching noses and lips. Hard not to find that appealing! True underground hibernators, 13-line ground squirrels can drop their heart rate to four to six beats per minute.
Woodchuck, whistle-pig or land beaver — all are names for our largest member of the Sciuridae family, the groundhog — and the only one to have a national holiday named in its honor. Groundhog Day originated with European settlers. They believed that badgers and hedgehogs could predict the weather; and with a shortage of both in the U.S. in early America, the groundhog became the stand-in. Also true hibernators, these rotund rodents must eat massive amounts of vegetation all summer, tipping the scales at 14 – 16 pounds before retreating to their underground dens in late October. Extraordinary excavators, woodchucks can move 700 pounds of dirt to dig their underground home. Their dens, which can extend 40 feet or more, have separate chambers for the seasons and even house a bathroom. But their architectural skills don’t end there. They even incorporate an incline to prevent flooding. Can they predict the weather on Feb. 2? One thing is for sure: They don’t even emerge from their burrows until mid-March.
You may remember Rocket J. Squirrel, the flying squirrel from the Rocky and Bullwinkle cartoons. If you were a keen observer, you would notice that Rocky did, in fact glide, not fly. Our smallest tree squirrel at only two ounces, the flying squirrel is equipped with a patagium, a section of loose skin along the side of its body that enables it to parachute up to 25 feet! No flapping; just some twisting to avoid obstacles. Equipped with big eyes and whiskers for feelers, these squirrels are nocturnal and secretive, so sightings are rare.
Two species of tree squirrels in DuPage County are the eastern gray (Sciurus carolinensis) and the fox (Sciurus niger). The reddish brown fox squirrels are the larger at 20 inches while the petite grays max out at 18 inches. They prefer nesting in hollow trees but have evolved to build leaf nests.
There was a time when seeing a squirrel in a city park was an anomaly. Squirrels were almost eradicated from cities in the early 1800s. But thanks to a few squirrel-loving individuals, these furry rodents were reintroduced to Franklin Square in Philadelphia in 1847 with the intent to “beautify and add interest to the parks” and teach young boys especially how to be kind to animals. The concept caught on, and today it’s almost impossible not to see these scurrying little acrobats happily adorning our suburban landscape.
They keep their “cache.” Gray squirrels “scatter hoard” their nuts, remembering the general location of the lot but not the individual nut. Masters of deception, this squirrel will even pretend to bury a nut if another squirrel is watching. If it already buried a cache, it’ll wait until the other squirrel is gone and move it to another location. Squirrels have been known to smell nuts under a foot of snow! What happens to the forgotten acorns? They become trees.
If you’ve ever marveled at how a tree squirrel can hang by its back toenails and stretch out its forearms to pilfer your bird feeder, here is your answer: Its hind leg joints are hypermobile or double-jointed. These leg joints can rotate 180 degrees in order to hang from trees or overhangs. This adaptation allows the squirrel to descend a tree head-first, a feat that mystifies many a family dog.
Rodent teeth never stop growing and even self-sharpen. The main body of the rodent incisor is made of dentine, but its front surface is covered by a thick, hard orange-colored layer of enamel. The upper incisors grind against the lowers while chewing, creating a continually growing and self-sharpened edge.
Squirrels see in color but struggle to distinguish red from green, which may explain why they sometimes have difficulty crossing streets — or take bites out of your unripe tomatoes.
Ben Franklin was a true squirrel lover. He brought a young gray squirrel across the Atlantic Ocean to Great Britain to give to a friend’s daughter as a pet. “Mungo” the squirrel became a treasured pet but unfortunately met his demise while crossing a dog’s path on his attempt to escape captivity. Ben Franklin immortalized the unfortunate Mungo in an epitaph in 1772.
They don’t like to, but squirrels can swim!
Want to learn more about squirrels? Visit our tree squirrels page for tips to live in harmony with these creatures in your backyard.