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Hibernation and Daily Torpor in Two Pygmy Possums (Cercartetus Spp., Marsupialia)

Fritz Geiser
Physiological Zoology
Vol. 60, No. 1 (Jan. - Feb., 1987), pp. 93-102
Stable URL: http://www.jstor.org/stable/30158631
Page Count: 10
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Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Hibernation and Daily Torpor in Two Pygmy Possums (Cercartetus Spp., Marsupialia)
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Abstract

The physiology of torpor was investigated in the pygmy possums Cercartetus concinnus (18 g) and C. lepidus (12 g). Body temperatures ($T_{b}$) during torpor remained within 1 C of air temperature ($T_{a}$) and showed a minimum of about 5 C in both species. Oxygen consumption ($\dot{V}O_{2}$) during torpor was reduced to about 0.05 liters O₂/kg h, which amounts to only 1% of the rate of normothermic animals. Below $T_{a}$ of 5 C, the metabolism during torpor increased with a further decrease in $T_{a}$, while $T_{b}$ was regulated at about 5 C. Rates of arousal were faster than predicted for endothermic vertebrates of comparable size. Duration of torpor bouts ranged from less than a day to a week, with the longest bouts occurring at $T_{a}$ < 10 C. The physiological characteristics of torpor in these two marsupial species are qualitatively and quantitatively similar to those of placental hibernators.

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