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Hibernation in the tropics: lessons from a primate
Kathrin H Dausmann1, Julian Glos, Jörg U Ganzhorn
1Department of Animal Physiology, Institute of Biology, Philipps-University, Karl-von-Frisch-Str. 8, 35043 Marburg, Germany. dausmann@staff.uni-marburg.de
Summary
Malagasy lemurs, or Cheirogaleus medius, hibernate without spontaneous arousals, challenging the definition of mammalian hibernation. Their body temperature passively tracks ambient conditions, redefining hibernation
Area of Science:
- Zoology
- Ecology
- Physiology
Background:
- The Malagasy primate Cheirogaleus medius undergoes a prolonged 7-month hibernation period.
- Hibernation occurs in natural environments where ambient temperatures can exceed 30°C.
- Spontaneous arousals were previously considered obligatory for all hibernating mammals.
Purpose of the Study:
- To investigate the hibernation patterns and body temperature regulation of Cheirogaleus medius in their natural habitat.
- To determine the role of ambient temperature and thermal insulation on hibernation behavior.
- To re-evaluate the definition of hibernation based on observed physiological responses.
Main Methods:
- A field study was conducted on Cheirogaleus medius during their hibernation period.
- Body temperature fluctuations were monitored in relation to ambient temperature.
- Hibernation sites, specifically tree holes and large trees, were analyzed for thermal insulation properties.
Main Results:
- Most lemurs exhibited body temperatures fluctuating between 10°C and 30°C, passively tracking ambient temperature.
- These lemurs did not display spontaneous arousals, contradicting previous assumptions about mammalian hibernation.
- Lemurs hibernating in well-insulated large trees maintained a stable body temperature around 25°C and showed regular arousals.
Conclusions:
- Maximum body temperature is identified as a critical factor triggering arousals during hibernation.
- Hibernation is not exclusively linked to low body temperatures, challenging the traditional definition.
- The study suggests that low body temperature should be removed from the obligatory definition of mammalian hibernation.
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