Michigan is home to a fascinating, yet often unseen, group of mammals: flying squirrels. While their name might suggest true flight, these creatures are actually adept gliders, silently navigating the nighttime canopy. Two distinct species inhabit the state, each with unique characteristics and preferred environments. Their nocturnal habits make encounters with them rare.
Species in Michigan
Michigan hosts two species of flying squirrels: the Northern Flying Squirrel (Glaucomys sabrinus) and the Southern Flying Squirrel (Glaucomys volans). The Northern Flying Squirrel is generally larger, measuring between 10 to 14 inches in body length and weighing 75 to 140 grams. Its fur is brownish-gray on top, with white-tipped fur on its underside. In contrast, the Southern Flying Squirrel is smaller, typically ranging from 7.9 to 11.2 inches and weighing 38 to 90 grams. Its upper fur is grey-brown, complemented by a cream-colored belly.
These two species also exhibit different distributions across Michigan. The Northern Flying Squirrel is primarily found in the northern Lower Peninsula and the Upper Peninsula, preferring older, closed-canopy boreal or mixed hardwood-coniferous forests. The Southern Flying Squirrel, historically found in the southern Lower Peninsula, has expanded its range and can now be found throughout the Lower Peninsula. This range expansion is attributed to a warming climate, potentially leading to increased overlap between the two species.
Unique Adaptations and Behavior
Flying squirrels move through trees using a patagium. This loose, furred membrane of skin extends from their wrists to their ankles on both sides of their body. When a squirrel launches itself from a tree, it stretches this membrane, transforming its body into an aerodynamic parachute. This allows them to glide significant distances, with recorded glides reaching up to 300 feet, and they can even steer and change direction mid-air using their limbs and flattened tail.
These squirrels are almost entirely nocturnal, a behavior that helps them avoid daytime predators like hawks and owls. Their large, dark eyes are specifically adapted for navigating in low-light conditions. They are most active during two distinct periods: approximately one hour after sunset for about two hours, and again for 1.5 to 2 hours before sunrise. During the day, they typically rest curled in a tight ball within tree cavities or nests.
Both species are omnivorous, consuming a diverse diet that includes nuts, seeds, fruits, and insects. Southern Flying Squirrels are more carnivorous, supplementing their diet with bird eggs, young birds, and carrion. Northern Flying Squirrels have an affinity for fungi, especially truffles, and play a role in dispersing fungal spores throughout forest ecosystems. Southern Flying Squirrels are social, often forming communal nests, particularly in winter, where groups of up to 20 individuals may huddle together to conserve warmth.
Where to Find Them in Michigan
Flying squirrels thrive in mature forests, parks, and other woodlands that offer abundant tree cavities for shelter. These cavities, often created by woodpeckers or resulting from natural decay in snags (dead standing trees), are important for nesting and winter denning.
While they are present across much of Michigan, spotting a flying squirrel can be challenging due to their nocturnal habits. Observant individuals might catch a glimpse of them by looking up into the canopy at night, especially near mature trees or bird feeders. Using a red light can sometimes aid in viewing their activity without disturbing them.
Living Alongside Flying Squirrels
Flying squirrels play an ecological role within Michigan’s forest ecosystems. The Northern Flying Squirrel is listed as a “Special Concern” species in Michigan, indicating that its population is rare or uncertain, though it is not legally protected under the state’s endangered species act. The Southern Flying Squirrel is considered common throughout its range. Both species are protected in Michigan and do not have a hunting season.
Coexisting with these shy creatures involves respecting their habitat and nocturnal routines. Homeowners can support local populations by preserving mature trees and snags on their property, as these provide shelter and nesting sites. To discourage them from entering human dwellings, it is advisable to trim tree branches that are close to the house, as these can serve as launching points for glides onto roofs. Flying squirrels are generally timid and pose no threat to humans, making observation from a distance the recommended approach if one is encountered.