Food
Southern flying squirrels are primarily vegetarian, but will occasionally eat animal foods. Nuts, primarily acorns and hickory nuts, are preferred foods and make up the bulk of the diet. Flying squirrels will also consume various seeds, fruits, berries, mushrooms, buds, flower blossoms and tree bark. Animal items that occasionally may be eaten include insects, bird eggs and nestlings, small nestling mammals, carrion, and adult shrews and mice.

Nuts are gathered and stored as winter approaches. The shortening of day length rather than temperature triggers the urge to store food. Nuts are buried individually or are cached in nest cavities or other cracks and crevices in trees. Several hundred nuts can be stored in a night. In good nut-production years, the stored nuts carry the squirrels through the winter and even into spring and summer. Nuts are eaten in a characteristic pattern. Flying squirrels usually cut a fairly smooth circular or oval opening on the side or end of a nut. On larger, heavy-shelled nuts they will make a second opening or remove an entire end in a single cut. Other tree squirrels usually crush nuts without leaving the shells intact.

The feeding pattern of flying squirrels more closely resembles that of deer mice or white-footed mice, which also inhabit cavities and nest boxes in southeastern Nebraska, but these species usually do not eat large, heavy-shelled nuts, and their tooth marks are finer. Flying squirrels will accept a "helping hand" by visiting bird feeders where they consume seeds, suet and peanut butter.

Limiting Factors
Flying squirrels have been known to live 13 years in captivity, but seldom live five years in the wild. A variety of predators and internal and external parasites can affect them. Predators include owls, domestic cats, hawks, snakes, bobcats, raccoons, weasels and foxes. Predation is probably no more significant for flying squirrels than it is for other tree squirrels. External parasites reported from flying squirrels include fleas, lice and mites, and internal parasites include nematodes and protozoans. None of those parasites are known to be substantial limiting factors. Few diseases have been reported in flying squirrels, and none are thought to be significant.