Thermoregulatory responses of a hibernator to hypothalamic and ambient temperatures

Steven H. Mills, Virginia M. Miller, Frank E. South

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Local cooling or heating of the hypothalamus of yellow bellied marmots elicited appropriate thermoregulatory responses to maintain body temperature. Increases in EMG, heart rate, and oxygen consumption were observed during hypothalamic cooling. Conversely, hypothalamic heating generally decreased thermogenic parameters toward minimal levels. Normothermic marmots retained thermoregulatory heat production throughout the year although loss of vasomotor regulation seemed to occur as they prepared for hibernation. The relationship between manipulated changes in hypothalamic temperature and induced changes in oxygen consumption was linear. This proportional relationship at one air temperature (15 °C) was parallel and displaced to the right of that relationship obtained at a lower air temperature (10 °C). These results are consistent with the hypothesis that hypothalamic regulation of body temperature in normothermic marmots is similar to that of nonhibernating mammals, although vasomotor regulation may differ.

Original languageEnglish (US)
Pages (from-to)465-472
Number of pages8
Issue number5
StatePublished - Oct 1974

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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