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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References

SHOWING 1-10 OF 53 REFERENCES
Correlations of plasma lipid metabolites with hibernation and lactation in wild black bears Ursus americanus
TLDR
Findings indicate a strong correlation between plasma lipid metabolites and the denning period in a wild population of black bears.
Lactation during Hibernation in Wild Black Bears: Effects on Plasma Amino Acids and Nitrogen Metabolites
TLDR
Results show that lactation during hibernation is an additional metabolic challenge that results in increased mobilization of individual plasma amino acids and no accumulation of nitrogen end products, underlining the remarkable efficiency of amino acid and urea recycling in denning female black bears.
BODY MASS AND LIPID CHANGES BY HIBERNATING REPRODUCTIVE AND NONREPRODUCTIVE BLACK BEARS (URSUS AMERICANUS)
TLDR
It was showed that pregnant females in a state of diapause during early winter had about 89% larger fat depots than did nonreproductive females going into hibernation, and rates of overall protein loss were relatively small.
Endocrine and electrophoretic profiles during pregnancy and nonpregnancy in captive female black bears
TLDR
Results suggested that pseudopregnancy, implantation failure, or fetal resorption may occur in black bears, with pregnant bears showing no change between implantation...
Protein metabolism in the black bear before and during hibernation.
TLDR
It is speculated that increased protein turnover suggests a strongly acting protein-anabolic mechanism that would tend to compete with other catabolic pathways for amino acids in the active state in spring.
Hibernating black bears have blood chemistry and plasma amino acid profiles that are indicative of long-term adaptive fasting
TLDR
Blood samples were drawn from six black bears active in the summer and six others in early and late hibernation, suggesting a dynamic process of adaptive fasting and protein conservation during the winter with a mobilization of non-myofibrilar collagen and perhaps smooth muscle protein reserves to augment a potential but slight increased breakdown of skeletal muscle during the late winter.
Hibernation in Black Bears: Independence of Metabolic Suppression from Body Temperature
TLDR
The pronounced reduction and delayed recovery of metabolic rate in hibernating bears suggest that the majority of metabolic suppression during hibernation is independent of lowered body temperature.
Behavior, Biochemistry, and Hibernation in Black, Grizzly, and Polar Bears
Annual behavioral and biochemical patterns of black bears (Ursus americanus), grizzly bears (Ursus arctos horribilis), and polar bears (Ursus maritimus) were reviewed. We propose that black and
Change in body weight of mothers and neonates and in milk composition during denning period in captive Japanese black bears (Ursus thibetanus japonicus).
TLDR
Japanese black bears showed remarkable efficiency in the use of energy for reproduction during the fasting period, and the milk had high fat and low sugar concentrations, which indicates that mother bears used the fat accumulated prior to denning for their main energy source when raising cubs.
Seasonal patterns in the physiology of the European brown bear (Ursus arctos arctos) in Finland.
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