Monday, January 1, 2018

Nature: Ohio scientists finally learning flying squirrels' secrets

A southern flying squirrel in Athens County/Jim McCormac

December 31, 2017

Jim McCormac

Perhaps no one knows as much about southern flying squirrels as Don Althoff. The professor of biology at Rio Grande College in southern Ohio has devoted two decades of study to these fascinating mammals.

I spent one early-December day shadowing Althoff as he conducted squirrel research in the rugged, forested hills of rural Athens County. We weren’t alone. The squirrels intrigue many of his students, and at least 15 of them joined us.

While largely out of sight and mind, flying squirrels are often the most common of our squirrels, at least in wooded habitats. They frequently occur in well-treed urban neighborhoods, including many in Columbus and its suburbs.

But southern flying squirrels are strictly nocturnal. Sometimes they’ll visit bird feeders, and if the feeders are lit by nightlights, people may notice them. Sometimes slathering peanut butter on tree trunks lures them in — Jif is irresistible to the elfin fliers.

A flying squirrel is much smaller than the more familiar, daytime-active gray and fox squirrels, which outweigh them by factors of 9 and 11, respectively. When seen in the flesh, a flying squirrel appears impossibly tiny: a lemur-eyed woodland sprite appended with a miniature beaver tail.

The indefatigable Dr. Althoff goes to great lengths to connect with his subjects. He has hung dozens of wooden nest boxes at five southeastern Ohio sites, all of which are far from the beaten path. Each box is about 12 feet aloft, tacked to a tree trunk.

Working a “squirrel trail” means lugging a large ladder and various research gear through dense woods and up and down steep slopes.

During the day, the squirrels hole up in cavities and readily adopt artificial boxes. Our expedition inspected 25 of them, and four boxes contained a total of 19 squirrels. The wee beasts are highly social and prone to sharing cavities. Althoff’s record is 13 in one box.

Between the mammals’ shared body heat and the insulating effect of plant material they place in the cavity, the inner box temperature remains quite toasty — an advantage on frigid winter days.

When researchers arrive at a box, they prop a ladder into place and go up. They quickly plug the entrance hole and bring down the box. An Althoff-engineered tube system safely funnels the squirrels from the box, and each is inspected, its weight and sex recorded. Each also gets a small ear tag for future identification and is photographed and released.

A squirrel’s liberation is interesting. After being placed on a tree trunk, it’ll typically scamper high at lightning speed. Then, earthbound observers are sometimes treated to a spectacular glide.

Flying squirrels are endowed with a membranous web of skin, called a patagium, between their fore and hind legs. When an animal throws its legs out upon launch, it becomes a mammalian parasail.

While the furry batmen can’t sustain flight, their glides can span hundreds of feet. They adeptly jig and jag to avoid limbs and trees, and sail unerringly to a desired target. Just before the squirrel lands, it throws its flat, wide tail upward, which acts as an air brake. Upon landing it runs to the opposite side of the trunk — perhaps a built-in behavior to thwart owls that might be in pursuit.

The only comprehensive treatise on Ohio’s mammals is Jack Gottschang’s book “A Guide to the Mammals of Ohio” (1981). In the southern flying squirrel account, he states, “No one has studied it in detail in Ohio.”

I’m glad there are intellectually curious researchers such as Althoff who attempt to unravel the mysteries of little-known creatures such as flying squirrels. Because of his work, we better understand their abundance, population cycles, reproduction, food requirements and preferred habitats.

Naturalist Jim McCormac writes a column for The Dispatch on the first, third and fifth Sundays of the month. He also writes about nature at

A southern flying squirrel in flight/Jim McCormac


Anonymous said...

I would like to put boxes up for the squirrels. I have the perfect habitat and believe I saw a pair this past summer but could not figure out what they were. What are the specs for constructing a box for them?

Jim McCormac said...

The following link has good nest box plans:

Auralee said...

I love your good-old "whack the tree with a stick" technique for encouraging the little rodents to leave their lair!

Unknown said...

I failed to get trailcam pics of these little guys out here in Southwest Ohio. Instead it was the raccoon and possum show all night at several locations. Any advice on how to get my camera lens on one of these fellows in 2018? I think I saw one fly down to the ground at Miami Whitewater one evening about 20 years ago! That was my only unconfirmed sighting. Any help would be greatly appreciated! Your blog is an inspiration.

Jim McCormac said...

Thanks as always for your comment, Auralee, and say hi to Jim! I wish I could offer good advice, Mike, but I have essentially zero experience with trail cams. If you live in or near woods that have the squirrels, slathering crunchy peanut butter on tree trunks can lure them in, as can bird feeders - just have to watch them after dark.

Anonymous said...

Hi Jim. Have these little critters on my wooded property Pike county on Scioto river. Found article interesting. Gary Wayne


As always, click the image to enlarge At the onset of last Monday's aquatic expedition (perhaps more on that later) to Rocky Fork ...