Craig Frank, Ph.D., associate professor of biology, has received a $293,000 grant from the National Science Foundation (NSF) to undertake a three-and-a-half-year project on the hibernation patterns of ground squirrels living at high altitudes.
The study is meant to determine the role of dietary polyunsaturated fatty acids (PUFAs) in the over-winter survival rate of golden-mantled ground squirrels. The squirrels, which live at an elevation of approximately 13,000 feet in California’s White Mountains, are one of 75 species of mammals that hibernate to survive the winter.
Frank said that short-term reductions in dietary PUFAs can strongly influence the squirrels’ hibernation ability and, thus, affect the species’ over-winter survival. Generally, the more PUFAs in a golden-mantled squirrel’s body, the better it hibernates. A corresponding field study will measure the relationship between elevation, temperature and the levels of PUFA content of food plants. PUFAs in plants have been shown to decrease with climate warming, Frank said.
“This project will provide new insights into the physiological ecology of mammalian hibernation,” said Frank, a mammalian ecologist who has been studying ground squirrels for 20 years.
“Ecosystems on the tops of the mountains are really temperature dependent,” he explained. “Animals live there because the high altitude offers their ideal habitat. If that climate changes, the animals become trapped between a peak that is warming, and the base of the mountain that is already too warm; their [habitat]band in between gets narrower and narrower as climate change continues.”
Frank and his team of researchers plan to fit approximately 120 squirrels living at four sites in the mountains with radio telemetry collars to measure their body temperatures. The scientists will measure each squirrel’s PUFA level before releasing it.
Readings from the collars will be taken by an automated radio receiver system every one to two hours from late August until mid-June, over three consecutive years. Since an animal’s body temperature during hibernation drops to nearly the same temperature as its surroundings, that data will show when and for how long the animals experience torpor.
Frank also has been researching hibernation patterns of the free-ranging eastern chipmunk at Fordham’s Louis Calder Center since 2000. His research documenting the correlation between climate change and hibernating patterns among the chipmunks was used in applying for the latest NSF grant, his fourth and largest.
The ultimate goal of the study is to help scientists develop a mathematical model to accurately predict the effects of climate warming on hibernators.
“We are trying to elucidate the basic principles that govern the hibernation of all mammals, and how these [principles]respond to the effects of climate change,” Frank said.