Squirrels Reveal Bits of Hibernome

Mammalian hibernators are unique in their ability to cope with freezing temperatures. Some mammals can lower their body temperatures to as low as –2.9°C for several weeks. In the golden-mantle ground squirrel, Spermophilus lateralis, this period of low body temperature, called torpor, is interrupted by arousals during which body temperature rises as much as 30°C in a matter of hours. Squirrels cannot survive frosty winters without these arousals. But hibernation researchers know very little about the proteins expressed during arousals that allow squirrels to re-enter torpor after arousals. To investigate the physiology of hibernation, Elaine Epperson and colleagues from the University of Colorado turned to the differential expression of hundreds of proteins, the proteome, or the squirrels’ ‘hibernome’.