The northern flying squirrel, Glaucomys sabrinus, occurs in part of Alaska, across most of Canada, in parts of the eastern and western United States, and in the Great Lakes region of the United States. The species occurs in many of Utah's mountainous areas, primarily in mature coniferous forests and riparian zones.
Females may produce one or two litters of two to six young during spring and summer each year. Northern flying squirrels eat fungi and lichens, as well as nuts, seeds, insects, and fruits. Nests are usually constructed inside hollow trees, but are sometimes constructed on tree branches. The species is nocturnal and active throughout the year. Northern flying squirrels cannot fly, but they can use the loose folds of skin on their sides to glide from tree to tree.