Freeze avoidance in a mammal: body temperatures below 0 degree C in an Arctic hibernator

Science. 1989 Jun 30;244(4912):1593-5. doi: 10.1126/science.2740905.


Hibernating arctic ground squirrels, Spermophilus parryii, were able to adopt and spontaneously arouse from core body temperatures as low as -2.9 degrees C without freezing. Abdominal body temperatures of ground squirrels hibernating in outdoor burrows were recorded with temperature-sensitive radiotransmitter implants. Body temperatures and soil temperatures at hibernaculum depth reached average minima during February of -1.9 degrees and -6 degrees C, respectively. Laboratory-housed ground squirrels hibernating in ambient temperatures of -4.3 degrees C maintained above 0 degree C thoracic temperatures but decreased colonic temperatures to as low as -1.3 degrees C. Plasma sampled from animals with below 0 degree C body temperatures had normal solute concentrations and showed no evidence of containing antifreeze molecules.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antifreeze Proteins
  • Arctic Regions
  • Arousal
  • Body Temperature Regulation
  • Body Temperature*
  • Female
  • Freezing*
  • Glycoproteins / analysis
  • Hibernation*
  • Male
  • Sciuridae / physiology*


  • Antifreeze Proteins
  • Glycoproteins