Northern Flying Squirrel
Glaucomys sabrinus ranges from the treeline in Alaska and Canada southward in the west to northern California and Colorado, in the middle of the continent to central Michigan and Wisconsin, and in the east to northern North Carolina and Tennessee. Island populations exist in areas of high elevation in other parts of the United States, including the southern Appalachian Mountains, the Black Hills, and the Sierra Nevada. Most often found in areas dominated by conifers, northern flying squirrels can also be relatively abundant in deciduous and mixed coniferous/deciduous forests. Glaucomys sabrinus has been found in diverse areas including regions dominated by spruce, fir, and mixed hemlocks, in beech maple forests, and in areas dominated by white spruce and birch with interspersed aspen groves. The northern flying squirrel often nests in conifers 1 -18 meters above the ground. The nests are made of twigs and bark, and they are softened with feathers, fur, leaves, and conifer needles.
Northern flying squirrel
Glaucomys sabrinus has silky grey and cinnamon brown fur, with white tipped and grey based belly hairs. Northern flying squirrels have a furred patagium (fleshy membrane) that extends from the wrist of the foreleg to the ankles of the hind leg. The tail is furred, flattened, rounded at the end, and long (80% of the length of the head and body). Glaucomys sabrinus has large black eyes, which they use for nighttime activity. Southern flying squirrels, which appear similar to the northern flying squirrels, can be distinguished because they are smaller and the hairs on the belly are often white all the way to the base of the hair.
Reproduction
Courtship begins in March and may continue until late May. One litter is born per year, and the female raises the young without the help of the male. Copulation occurs in early spring and is followed by a gestation period of 37 – 42 days. Usually, 2 -4 young are born, though litters as small as 1 and as large as 6 have been recorded. Newborns are poorly developed; they weigh 5 -6 grams, and they have closed eyes and ears, fused toes, and a cylindrical tail. By the sixth day the toes are separated, and the eyes open after 31 days. Young leave the nest at 40 days and are totally weaned after two months, though they may remain with the mother another month. Flying squirrels breed in the first summer after their birth. Young flying squirrels are born helpless and are nursed and cared for by their mothers until they reach independence.
Behavior
Northern flying squirrels sometimes share nests and may live in groups of up to 8 adults and juveniles. Individuals of Glaucomys sabrinus aggregate into single-sex groups for warmth during the winter. Strictly nocturnal, northern flying squirrels are active for about two hours beginning an hour after sunset, and again for an hour and a half to two hours before sunrise. Depending on the habitat, the home range of northern flying squirrels ranges from 0.8 hectares to 31 hectares. Female northern flying squirrels are territorial, but males are not. The population density can be as high as 10 squirrels per hectare in favorable conditions. Northern flying squirrels emit a soft low chirp, and they cluck when distressed. They have excellent senses of hearing, smell, vision, and touch.
Food Habits
Glaucomys sabrinus has a characteristic squirrel diet. They eat nuts, acorns, fungi, and lichens, supplemented by fruits, buds, sap and the occasional insect and bird egg. Northern flying squirrels diverge from many squirrels in that lichens and fungi are a large portion of the diet and are not just supplements. It is thought that northern flying squirrels hoard food for the winter, though this has not been confirmed. In captivity they should be offered a complete diet of rodent lab blocks, mushrooms, and bits of fruit or veggies regularly. Cheerios or wheat bread are great treats, in small quantities. Do NOT feed chocolate, fried foods, salted foods, candy or junk food! They may enjoy crickets and mealworms if they are captive bred, never feed wild insects as they may carry parasites. Vitamins, like Nutri-Cal are a good addition to their diet, and added calcium during nursing and growth due to demands on their systems at those times, but take care not to overdo it. Water bottles should be used to proved constant, clean water. Ceramic or stoneware food dishes work well for keeping seeds or fresh foods off the floor, and a wire mesh hopper that allows them to eat the lab blocks through without extra waste.
