PITTSBURGH - A team of researchers led by Carnegie Museum of Natural History scientist Joseph Merritt has uncovered how the southern flying squirrel (Glaucomys volans) manages to stay active throughout winter. It was previously unknown how the smallest of North American flying squirrels, characterized by a high surface-to-volume ratio resulting in rapid heat loss, was able to be active throughout the chilling winter months.
After careful study in controlled conditions at Powdermill Biological Station, the field research station of Carnegie Museum of Natural History, Merritt and his colleagues David A. Zegers and Lynda Rose discovered how G. volans saves energy, survives food shortages, and copes with the stress of cold winters.
"This squirrel does not hibernate," Merritt said. "But it stores nuts and food, grows thick winter pelage, forages in ameliorating microclimates, and huddles in a well-insulated communal nest in a tree cavity, along with 10 or more other individuals. After keeping its metabolism low and under control by these strategies, it also generates heat quickly for winter night-time activities by "non-shivering thermogenesis" - rapid heat production that is due to a small bundle of tissue located between its shoulder blades"
A grant from the Growing Greener Program of the Commonwealth of Pennsylvania will fund additional research into flying squirrels this year.
The research includes habitat requirements and an investigation of the ecological link between the feeding habits of flying squirrels, underground fungi and the dispersal and colonization of new trees in forested areas.
Merritt is the resident director of Powdermill Biological Station. He is a physiological ecologist specializing in adaptations of small mammals to cold. Merritt is the author of "Guide to Mammals of Pennsylvania," published by the University of Pittsburgh Press, and editor of several technical monographs on specific taxa of mammals. He has served on the editorial committee of the American Society of Mammalogists since 1990, and as the managing editor of the Journal of Mammalogy.