The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

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Canals M., Rosenmann M. and Bozinovic F. 1997. Geometrical aspects o f the energetic effectiveness of huddling in small mammals. Acta Theriologica 42: 321-328.Reduced energy expenditure resulting from huddling in small mammals is mainly attributed to the reduced surface area/volume ratio of the huddling group. Here we propose a model to account for the reduction of the relative exposed area of grouped animals and for the diminution of metabolic rate during huddling. We attempt to explain mechanistically how changes in energy savings may operate. We applied our model to results obtained by grouping deformable bodies, and also laboratory meas urements o f oxygen consumption on huddling small mammals of four species. We found a small amount of diversity in the energetic efficiency of huddling. We estimate that the average relative area lost during huddling ranged between 28.7 and 39.1%. The average huddling effectiveness in the studied species was 42%, which is a significant fraction of the energy/matter budget of a small mammal, especially under winter conditions.

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We examined the energetics of the living fossil microbiotheriid Dromiciops gliroides, a nocturnal and rare small marsupial, endemic to the northern portion of the temperate forest of southern South America. We investigated the effects of changes at ambient temperature and food restriction on the energetics and patterns of torpor. We determined whether they exhibit shallow daily torpor or deep prolonged torpor like some Australian marsupials. Thermal conductance was 92.5% of the expected value for a similarly sized eutherian and basal metabolic rate was 82.9 and 58.6% of the predicted value for standard metatherians and eutherians, respectively. Euthermic D. gliroides showed daily fluctuations in body temperature, being significantly higher during the night. Dromiciops gliroides entered torpor and aroused spontaneously. The duration of torpor bouts increased in response to decreasing ambient temperature; torpor bout duration ranged from 10 h at 20 degrees C to 120 h at 12.5 degrees C. This study is the first record of deep torpor or hibernation for a South American mammal. Torpor in this species as well as in marsupials in general appears to be an opportunistic response to unpredictable biotic and abiotic conditions.

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