Pregnancy during hibernation in Japanese black bears: effects on body temperature and blood biochemical profiles

@inproceedings{Shimozuru2013PregnancyDH,
  title={Pregnancy during hibernation in Japanese black bears: effects on body temperature and blood biochemical profiles},
  author={Michito Shimozuru and Ruriko Iibuchi and Takuro Yoshimoto and Akiko Nagashima and Jun Tanaka and Toshio Tsubota},
  year={2013}
}
Abstract Bears from the family Ursidae are the only terrestrial mammals that go through gestation, parturition, and lactation during hibernation. This is the 1st study to examine the influence of reproductive status (i.e., nonpregnant, pseudopregnant, or pregnant) on body temperature and blood biochemical profiles in hibernating black bears. Pregnant bears appeared to have higher and more stable body temperatures (37–38°C) than nonpregnant ones (34–36°C) during pregnancy, which was followed by… 
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Free-ranging pregnant brown bears in areas with high levels of human activities at the beginning of the denning period, as in the study area, might prioritize investing energy in early denning than in early parturition during years with favorable environmental conditions, as a strategy to prevent disturbances caused by human.
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Results show that muskox females use hypothermia during periods of resource scarcity, but also that the use of this strategy may be limited to non-reproducing females, and suggest a trade-off between metabolically-driven energy conservation during winter and sustaining foetal growth.
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Seasonal changes in the expression of energy metabolism-related genes in white adipose tissue and skeletal muscle in female Japanese black bears.
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Current knowledge about those heterothermic mammals that do not express torpor during reproduction are summarized and, in contrast, thoseheterothermic birds and mammal species that do use torporDuring reproduction are examined.
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There is a pressing need to understand better how developmental temperature impacts thermoregulatory responses to matched and mismatched thermal challenges in subsequent life stages to facilitate or constrain thermal adaptation over a lifetime.
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The MaxEnt model was used to simulate current and future distribution of the Asiatic black bear and its commonly used food (three Quercus spp.) in the NHP and predicted range reduction and extreme fragmentation in the habitats of all the QuercUS spp.
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TLDR
The results suggest that the increased levels of hepatic miRNA during hibernation negatively regulate the expression of targeted genes predicted to be involved in the transport of energy source and de novo fatty acid synthesis, is consistent with a regulatory role of these miRNAs in energy metabolism in hibernating black bears.
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Current knowledge about those heterothermic mammals that do not express torpor during reproduction are summarized and, in contrast, thoseheterothermic birds and mammals that are found in unpredictable habitats have relatively low reproductive costs, and thus rely on food that can be unpredictable or strongly seasonal.
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