By Susan Benson,
CNHM Director of Education
I must be crazy. While others are trying to squirrel-proof their feeders, this past Sunday I decided to feed them. I wanted to do some “scientific” observation of squirrels eating, so I put out some piles of sunflower seeds near the sliding glass doors on the patio. One that I’ve dubbed “chicken pants” would not come near, but along came another “braveheart” that wasn’t at all afraid. I watched it eat for a while, sharp claws and teeth at work, and then along came “chicken pants” who although was afraid of me, was not afraid of “braveheart.” I had never heard squirrels growl, but that was the only way I could describe their territorial attempts to claim the food piles. These two squirrels did not quite look alike, so I decided to research a little deeper.
In this part of Wisconsin we have two types of tree squirrels, the gray and the fox squirrel. The fox squirrel is bigger, and its fur is brown to gray, with a bushy tail that ends with tawny-tipped hairs. The gray squirrel is just a bit smaller, with gray color and a bushy tail tipped with white. As I read about these two squirrel species, I realized that “braveheart” was a fox squirrel, and “chicken pants” was a gray squirrel. We do indeed learn something every day.
Gray and fox squirrels have very sharp claws for climbing trees, and vibrissae, thick hairs or whiskers that are used as touch receptors to sense in their environment and help find their way in dark tree cavities. The conspicuous bushy tail of both squirrels assists them with communication, balance, covering as a blanket, and umbrella. Both squirrel species are both scatter-hoarders, hiding food in many small caches for later retrieval. Some cache sites are for shorter-term use that they eat within hours or days, or sometimes will re-bury at another site. It is believed that both squirrels make thousands of caches each season. Fox and gray squirrels both have very accurate spatial memory, using distant and nearby landmarks to retrieve their caches. Their sense of smell is then used as they approach more closely to the cache. In spite of these advantages, they often leave behind food supplies that germinate and become new trees.
Fox squirrels depend primarily on tree seeds for food, especially acorns and hazelnuts, and will also consume buds, fruits, cultivated grain, and insects. Gray squirrels have a more diverse diet, eating acorns and other tree nuts, fruits, fungi, insects, inner tree bark, sap, and underground sections of plants. They will also eat small rodents, including other squirrels, and will raid bird nests for eggs and young.
Gray squirrels are one of the few mammal species that can descend a tree face-first, turning their feet so the claws of their hind paws are pointing backward, gripping the bark. Fox Squirrels are non-territorial, and spend more time on the ground than the gray squirrel. They are still, however, agile climbers. They can span fifteen feet in horizontal leaps, and fall twenty feet to a soft landing on a limb below.
Both species of squirrels construct nests called “dreys,” made of dry leaf and twig platforms high in the trees. Gray squirrels will use old woodpecker holes as dens to raise young, but only build dreys when cavities are not available. Fox squirrels also have winter dens that are usually hollow cavities in trees, in which communal denning can occur, and the home itself can be used by a succession of squirrels for thirty or more years.
Gray and fox squirrels have a large vocabulary. Gray squirrels use sounds and posturing, including a squeak similar to a mouse, a low pitched sound, a raspy, repeated “mehr” sound, and a chatter. Fox squirrels cluck, chuck, and warn the world of nearby threats with screams. They make high-pitched sounds when mating. When threatening another fox squirrel, they stand upright with their tail up high, flicking it.
Gray squirrels prefer mixed hardwood forests with mature, nut producing trees. Grays will usually stay very close to home, with a territory as small as 1,000 feet. Fox squirrels prefer agricultural areas mixed with forested woodlots, with a home range of 10-40 acres.
As I am writing this story, my fiancé has complained to me that these squirrels just chewed up a gas can. Are they chewing at something like this simply to keep their teeth sharpened? Is there anything they won’t chew? For whatever reason this squirrel chewed, we all know the rodents in our world bring us the occasional frustration, and for the most part, entertainment and joy.
For over 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, Our Shared Planet, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.