Flying squirrels belong to the tribe Pteromyini, a group of approximately 50 species of rodents known for their ability to glide through the forest canopy. These highly arboreal, strictly nocturnal mammals possess large eyes adapted for navigating the dark. They achieve their distinctive “flight” using the patagium, a specialized fold of skin stretching from wrist to ankle, allowing controlled glides between trees.
Identifying the North American Species
Longevity data primarily focuses on the two species native to North America. The smaller is the Southern Flying Squirrel (Glaucomys volans), measuring 8 to 10 inches in total length. This species is distributed widely across the eastern half of the United States.
Its relative, the Northern Flying Squirrel (Glaucomys sabrinus), is slightly larger, typically reaching 10 to 12 inches long. The two are also distinguished by their belly fur color; the Southern species has completely white fur underneath, while the Northern species’ belly fur is gray at the base. The Northern species has a more patchy geographical distribution, found in the coniferous forests of the Northeast, the West Coast, and the Appalachian Mountains.
Lifespan in the Wild vs. Captivity
The lifespan of a flying squirrel is dramatically curtailed in its natural habitat. The Southern Flying Squirrel (Glaucomys volans) typically lives for an average of only three to five years in the wild. The Northern Flying Squirrel (Glaucomys sabrinus) generally fares slightly worse, with a wild lifespan often less than four years.
This short existence contrasts sharply with the potential longevity observed in protected settings. In captivity, where they receive consistent food and are safe from predators, flying squirrels can live for over a decade. The average lifespan is often cited between 10 and 13 years, representing a threefold increase over their wild counterparts.
The maximum recorded lifespan for a Southern Flying Squirrel in captivity is a remarkable 19 years. This substantial disparity highlights the constant struggle for survival that defines their lives in the forest.
Environmental Pressures on Survival
High mortality rates begin immediately after birth, with many young succumbing to disease or predation before maturity. Newborns are helpless and must be cared for by their mother for about two months before they are fully weaned and capable of independent gliding. This early period of dependence leaves them highly vulnerable within their nest cavities.
Once mobile, they face a constant threat from specific nocturnal predators. The Great Horned Owl and other species of owls are highly effective hunters of flying squirrels, often catching them mid-glide or when they are foraging. Terrestrial predators like raccoons, bobcats, and black rat snakes also pose a significant risk, especially if the squirrel is forced to forage on the ground.
The availability of suitable habitat is another limiting factor that affects survival. Flying squirrels rely on old-growth forests with mature, large trees and snags for their nesting cavities and for the long gliding distances necessary for efficient travel. Habitat fragmentation, which isolates forest patches, reduces their ability to evade predators and find food, thereby increasing their exposure to risk.
Severe winter weather also poses a threat, requiring the squirrels to conserve energy and find adequate shelter. Southern Flying Squirrels often aggregate in large groups inside tree cavities to share warmth during cold periods. Failure to find sufficient shelter or cached food during prolonged cold snaps can lead to death by exposure or starvation.