Journal articles: 'Hibernation duration'

7

Xi, Li, and Michael D. Graham. "Intermittent dynamics of turbulence hibernation in Newtonian and viscoelastic minimal channel flows." Journal of Fluid Mechanics 693 (January 17, 2012): 433–72. http://dx.doi.org/10.1017/jfm.2011.541.

Full text

Abstract:

AbstractMaximum drag reduction (MDR), the asymptotic upper limit of reduction in turbulent friction drag by polymer additives, is the most important unsolved problem in viscoelastic turbulence. Recent studies of turbulence in minimal flow units have identified time intervals showing key features of MDR. These intervals, denoted ‘hibernating turbulence’ are found in both Newtonian and viscoelastic flows. The present study provides a comprehensive examination of this turbulence hibernation phenomenon in the minimal channel geometry, and discusses its impact on the turbulent dynamics and drag reduction. Similarities between hibernating turbulence and MDR are established in terms of both flow statistics (an intermittency factor, mean and fluctuating components of velocity) and flow structure (weak vortices and nearly streamwise-invariant kinematics). Hibernation occurs more frequently at high levels of viscoelasticity, leading to flows that increasingly resemble MDR. Viscoelasticity facilitates the occurrence of hibernation by suppressing the conventional ‘active’ turbulence, but has little influence on hibernation itself. At low Weissenberg number $\mathit{Wi}$, the average duration of active turbulence intervals is constant, but above a critical value of $\mathit{Wi}$, the duration decreases dramatically, and accordingly, the fraction of time spent in hibernation increases. This observation can be explained with a simple mathematical model that posits that the lifetime of an active turbulence interval is the time that it takes for the turbulence to stretch polymer molecules to a certain threshold value; once the molecules exceed this threshold, they exert a large enough stress on the flow to suppress the active turbulence. This model predicts an explicit form for the duration as a function of $\mathit{Wi}$ and the simulation results match this prediction very closely. The critical point where hibernation frequency becomes substantially increased coincides with the point where qualitative changes are observed in overall flow statistics – the transition between ‘low-drag-reduction’ and ‘high-drag-reduction’ regimes. Probability density functions of important variables reveal a much higher level of intermittency in the turbulent dynamics after this transition. It is further confirmed that hibernating turbulence is a Newtonian structure during which polymer extension is small. Based on these results, a framework is proposed that explains key transitions in viscoelastic turbulence, especially the convergence toward MDR.

APA, Harvard, Vancouver, ISO, and other styles

8

Frerichs, Kai U., and John M. Hallenbec. "Hibernation in Ground Squirrels Induces State and Species-Specific Tolerance to Hypoxia and Aglycemia: An In Vitro Study in Hippocampal Slices." Journal of Cerebral Blood Flow & Metabolism 18, no. 2 (1998): 168–75. http://dx.doi.org/10.1097/00004647-199802000-00007.

Full text

Abstract:

Hibernation in mammals is associated with a regulated depression of global cellular functions accompanied by reductions of cerebral blood flow that would render the brain profoundly ischemic under normal conditions. Homeostatic control is preserved, however, and brain damage does not occur. We investigated the possibility that hibernation not only confers tolerance to profound hypothermia, but also to hypoxia and aglycemia independent of temperature. Hippocampal slices from ground squirrels Citellus tridecemlineatus in both the active and hibernating states and from rats were subjected to in vitro hypoxia and aglycemia at incubation temperatures of 36°C, 20°C, and 7°C and evaluated histologically. A binary bioassay was used to determine the duration of hypoxia/aglycemia tolerated in each group. At all temperatures, slices from hibernating animals were most tolerant compared with both active squirrels and rats. Slices from active ground squirrels were more tolerant than rat at 20°C and 7°C but not at 36°C indicating a species-specific difference that becomes manifest at lower temperatures. These results indicate that hibernation is associated not only with tolerance to profound hypothermia but also to deprivation of oxygen and glucose. Because tolerance was already demonstrable at the shortest duration of hibernation studied, rapid therapeutic induction of a similar state may be possible. Therefore, identification of the regulatory mechanisms underlying this tolerance may lead to novel neuroprotective strategies.

APA, Harvard, Vancouver, ISO, and other styles

9

Wilbur, Sara M., Cody E. Deane, Greg A. Breed, C. Loren Buck, Cory T. Williams, and Brian M. Barnes. "Survival estimates of free-living arctic ground squirrels (Urocitellus parryii): effects of sex and biologging." Canadian Journal of Zoology 100, no. 4 (2022): 251–60. http://dx.doi.org/10.1139/cjz-2021-0156.

Full text

Abstract:

Hibernation is associated with long lifespan: on average, hibernating mammals live 15% longer than nonhibernators of equivalent mass. We investigated how survival varies with sex, season, and the deployment of biologgers in arctic ground squirrels (Urocitellus parryii (Richardson, 1825)), a widely distributed northern hibernator. The duration of hibernation in arctic ground squirrels differs markedly by sex: females hibernate 30% longer each year than males, a behavioural trait that could positively affect female survival. Additionally, males engage in aggressive territorial and food cache defense in spring and fall, which may decrease survival in this sex. From 13 years of mark–recapture data, we estimated apparent survival of arctic ground squirrels in Arctic Alaska (USA) using Cormack–Jolly–Seber models in program MARK. We found that females had higher annual survival ([Formula: see text] (95% confidence interval (CI): 0.469, 0.913)) than males ([Formula: see text] (95% CI: 0.416, 0.670)), with a maximum observed lifespan (10 years) that exceeded that of males (6 years). We also show that biologger use and implantation did not significantly impact survival. Quantifying basic arctic ground squirrel demographics from this well-studied population illustrates how sex-specific hibernation parameters may influence lifespan differences in male and female arctic ground squirrels and provides support for the safety of biologging devices.

APA, Harvard, Vancouver, ISO, and other styles

10

Ohtsuki, Toshiho, Howard Jaffe, Michael Brenner, et al. "Stimulation of Tyrosine Phosphorylation of a Brain Protein by Hibernation." Journal of Cerebral Blood Flow & Metabolism 18, no. 9 (1998): 1040–45. http://dx.doi.org/10.1097/00004647-199809000-00014.

Full text

Abstract:

Mammalian hibernation is a state of natural tolerance to severely decreased brain blood flow. As protein tyrosine phosphorylation is believed to be involved in the development of resistance to potentially cell-damaging insults, we used immunoblotting for the phosphotyrosine moiety to analyze extracts from various tissues of hibernating and nonhibernating ground squirrels. A single, hibernation-specific phosphoprotein was detected in the brain, but not in any other tissue tested. This protein, designated pp98 to reflect its apparent molecular weight, is distributed throughout the brain, and is associated with the cellular membrane fraction. The presence of the protein is tightly linked to the hibernation state; it is not present in contemporaneously assayed animals that are exposed to the same cold temperature as the hibernators, is present for the duration of a hibernation bout (tested from 1 to 14 days), and disappears within 1 hour of arousal from hibernation. The close association of pp98 with the hibernation state, its presence in cellular membranes, and the known properties of membrane phosphotyrosine proteins suggest that it may transduce a signal for adaptation to the limited availability of oxygen and glucose and low cellular temperature that characterizes hibernation in the ground squirrel.

APA, Harvard, Vancouver, ISO, and other styles

11

Prendergast, Brian J., David A. Freeman, Irving Zucker, and Randy J. Nelson. "Periodic arousal from hibernation is necessary for initiation of immune responses in ground squirrels." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 282, no. 4 (2002): R1054—R1062. http://dx.doi.org/10.1152/ajpregu.00562.2001.

Full text

Abstract:

Golden-mantled ground squirrels ( Spermophilus lateralis) undergo seasonal hibernation during which core body temperature (Tb) values are maintained 1–2°C above ambient temperature. Hibernation is not continuous. Squirrels arouse at ∼7-day intervals, during which Tbincreases to 37°C for ∼16 h; thereafter, they return to hibernation and sustain low Tbs until the next arousal. Over the course of the hibernation season, arousals consume 60–80% of a squirrel's winter energy budget, but their functional significance is unknown and disputed. Host-defense mechanisms appear to be downregulated during the hibernation season and preclude normal immune responses. These experiments assessed immune function during hibernation and subsequent periodic arousals. The acute-phase response to bacterial lipopolysaccharide (LPS) was arrested during hibernation and fully restored on arousal to normothermia. LPS injection (ip) resulted in a 1–1.5°C fever in normothermic animals that was sustained for >8 h. LPS was without effect in hibernating squirrels, neither inducing fever nor provoking arousal, but a fever did develop several days later, when squirrels next aroused from hibernation; the duration of this arousal was increased sixfold above baseline values. Intracerebroventricular infusions of prostaglandin E2provoked arousal from hibernation and induced fever, suggesting that neural signaling pathways that mediate febrile responses are functional during hibernation. Periodic arousals may activate a dormant immune system, which can then combat pathogens that may have been introduced immediately before or during hibernation.

APA, Harvard, Vancouver, ISO, and other styles

12

Jonasson, Kristin A., and Craig K. R. Willis. "Hibernation energetics of free-ranging little brown bats." Journal of experimental biology 215, Pt 12 (2012): 2141–9. https://doi.org/10.5281/zenodo.13527207.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation physiology and energy expenditure have been relatively well studied in large captive hibernators, especially rodents, but data from smaller, free-ranging hibernators are sparse. We examined variation in the hibernation patterns of free-ranging little brown bats (Myotis lucifugus) using temperature-sensitive radio-transmitters. First, we aimed to test the hypothesis that age, sex and body condition affect expression of torpor and energy expenditure during hibernation. Second, we examined skin temperature to assess whether qualitative differences in the thermal properties of the hibernacula of bats, compared with the burrows of hibernating rodents, might lead to different patterns of torpor and arousal for bats. We also evaluated the impact of carrying transmitters on body condition to help determine the potential impact of telemetry studies. We observed large variation in the duration of torpor bouts within and between individuals but detected no effect of age, sex or body condition on torpor expression or estimates of energy expenditure. We observed the use of shallow torpor in the midst of periodic arousals, which may represent a unique adaptation of bats for conservation of energy during the most costly phase of hibernation. There was no difference in the body condition of hibernating bats outfitted with transmitters compared with that of control bats captured from the same hibernaculum at the same time. This study provides new information on the energetics of hibernation in an under-represented taxon and baseline data important for understanding how white-nose syndrome, a new disease devastating populations of hibernating bats in North America, may alter the expression of hibernation in affected bats.

APA, Harvard, Vancouver, ISO, and other styles

13

Jonasson, Kristin A., and Craig K. R. Willis. "Hibernation energetics of free-ranging little brown bats." Journal of experimental biology 215, Pt 12 (2012): 2141–9. https://doi.org/10.5281/zenodo.13527207.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation physiology and energy expenditure have been relatively well studied in large captive hibernators, especially rodents, but data from smaller, free-ranging hibernators are sparse. We examined variation in the hibernation patterns of free-ranging little brown bats (Myotis lucifugus) using temperature-sensitive radio-transmitters. First, we aimed to test the hypothesis that age, sex and body condition affect expression of torpor and energy expenditure during hibernation. Second, we examined skin temperature to assess whether qualitative differences in the thermal properties of the hibernacula of bats, compared with the burrows of hibernating rodents, might lead to different patterns of torpor and arousal for bats. We also evaluated the impact of carrying transmitters on body condition to help determine the potential impact of telemetry studies. We observed large variation in the duration of torpor bouts within and between individuals but detected no effect of age, sex or body condition on torpor expression or estimates of energy expenditure. We observed the use of shallow torpor in the midst of periodic arousals, which may represent a unique adaptation of bats for conservation of energy during the most costly phase of hibernation. There was no difference in the body condition of hibernating bats outfitted with transmitters compared with that of control bats captured from the same hibernaculum at the same time. This study provides new information on the energetics of hibernation in an under-represented taxon and baseline data important for understanding how white-nose syndrome, a new disease devastating populations of hibernating bats in North America, may alter the expression of hibernation in affected bats.

APA, Harvard, Vancouver, ISO, and other styles

14

Jonasson, Kristin A., and Craig K. R. Willis. "Hibernation energetics of free-ranging little brown bats." Journal of experimental biology 215, Pt 12 (2012): 2141–9. https://doi.org/10.5281/zenodo.13527207.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation physiology and energy expenditure have been relatively well studied in large captive hibernators, especially rodents, but data from smaller, free-ranging hibernators are sparse. We examined variation in the hibernation patterns of free-ranging little brown bats (Myotis lucifugus) using temperature-sensitive radio-transmitters. First, we aimed to test the hypothesis that age, sex and body condition affect expression of torpor and energy expenditure during hibernation. Second, we examined skin temperature to assess whether qualitative differences in the thermal properties of the hibernacula of bats, compared with the burrows of hibernating rodents, might lead to different patterns of torpor and arousal for bats. We also evaluated the impact of carrying transmitters on body condition to help determine the potential impact of telemetry studies. We observed large variation in the duration of torpor bouts within and between individuals but detected no effect of age, sex or body condition on torpor expression or estimates of energy expenditure. We observed the use of shallow torpor in the midst of periodic arousals, which may represent a unique adaptation of bats for conservation of energy during the most costly phase of hibernation. There was no difference in the body condition of hibernating bats outfitted with transmitters compared with that of control bats captured from the same hibernaculum at the same time. This study provides new information on the energetics of hibernation in an under-represented taxon and baseline data important for understanding how white-nose syndrome, a new disease devastating populations of hibernating bats in North America, may alter the expression of hibernation in affected bats.

APA, Harvard, Vancouver, ISO, and other styles

15

Jonasson, Kristin A., and Craig K. R. Willis. "Hibernation energetics of free-ranging little brown bats." Journal of experimental biology 215, Pt 12 (2012): 2141–9. https://doi.org/10.5281/zenodo.13527207.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation physiology and energy expenditure have been relatively well studied in large captive hibernators, especially rodents, but data from smaller, free-ranging hibernators are sparse. We examined variation in the hibernation patterns of free-ranging little brown bats (Myotis lucifugus) using temperature-sensitive radio-transmitters. First, we aimed to test the hypothesis that age, sex and body condition affect expression of torpor and energy expenditure during hibernation. Second, we examined skin temperature to assess whether qualitative differences in the thermal properties of the hibernacula of bats, compared with the burrows of hibernating rodents, might lead to different patterns of torpor and arousal for bats. We also evaluated the impact of carrying transmitters on body condition to help determine the potential impact of telemetry studies. We observed large variation in the duration of torpor bouts within and between individuals but detected no effect of age, sex or body condition on torpor expression or estimates of energy expenditure. We observed the use of shallow torpor in the midst of periodic arousals, which may represent a unique adaptation of bats for conservation of energy during the most costly phase of hibernation. There was no difference in the body condition of hibernating bats outfitted with transmitters compared with that of control bats captured from the same hibernaculum at the same time. This study provides new information on the energetics of hibernation in an under-represented taxon and baseline data important for understanding how white-nose syndrome, a new disease devastating populations of hibernating bats in North America, may alter the expression of hibernation in affected bats.

APA, Harvard, Vancouver, ISO, and other styles

16

Filatova, T. S., and D. V. Abramochkin. "The Influence of Hibernation on Electrical Activity and Potassium Currents in Myocardium of Long-Tailed Ground Squirrel." Российский физиологический журнал им И М Сеченова 109, no. 6 (2023): 788–97. http://dx.doi.org/10.31857/s0869813923060031.

Full text

Abstract:

Hibernating mammals are capable of reducing the temperature of their bodies down to 0°C. During this process, their heart is highly resistant to the occurrence of arrhythmias caused by temperature fall. In this research we have for the first-time studied potassium currents in the myocardium of a hibernating mammal on the example of long-tailed ground squirrel (Citellus undulatus) and its change upon hibernation. Using patch clamp method, we studied transient outward current Ito and background inward rectifier current IK1 in isolated ventricular and atrial myocytes from summer (active) and winter (hibernating) ground squirrels. The study revealed, that at room temperature and at positive holding potentials peak amplitude of Ito in cardiomyocytes from hibernating group of animals is lower than that of the summer group. The downregulation of Ito upon hibernation was more pronounced in ventricular myocardium in comparison to that in atrial. Background inward rectifier current IK1 was enhanced in ventricular myocardium of winter group of animals, upon the adaptation to hibernation. In atrial myocardium there were no statistically significant differences of IK1 between the two groups. We also recorded action potentials in isolated ventricular cardiomyocytes. The duration of action potentials at the levels of 50 and 90% repolarization did not differ between the groups, we also did not find significant differences in maximum upstroke velocity and in the level of resting membrane potential. Taken together, the revealed differences in the amplitude of Ito and IK1 between active and hibernating ground squirrels can serve as mechanisms increasing the duration of refractory period and to maintaining the level of resting membrane potential at low temperatures.

APA, Harvard, Vancouver, ISO, and other styles

17

Boyles, Justin G., Virgil Brack, Katie E. Marshall, and Darwin Brack. "Shifts in population density centers of a hibernating mammal driven by conflicting effects of climate change and disease." Global Change Biology 30, no. 1 (2024): e17035. https://doi.org/10.5281/zenodo.14822244.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Populations wax and wane over time in response to an organism's interactions with abiotic and biotic forces. Numerous studies demonstrate that fluctuations in local populations can lead to shifts in relative population densities across the geographic range of a species over time. Fewer studies attempt to disentangle the causes of such shifts. Over four decades (1983–2022), we monitored populations of hibernating Indiana bats (Myotis sodalis) in two areas separated by ~110 km. The number of bats hibernating in the northern area increased from 1983 to 2011, while populations in the southern area remained relatively constant. We used simulation models and longterm weather data to demonstrate the duration of time bats must rely on stored fat during hibernation has decreased in both areas over that period, but at a faster rate in the northern area. Likewise, increasing autumn and spring temperatures shortened the periods of sporadic prey (flying insect) availability at the beginning and end of hibernation. Climate change thus increased the viability of northern hibernacula for an increasing number of bats by decreasing energetic costs of hibernation. Then in 2011, white-nose syndrome (WNS), a disease of hibernating bats that increases energetic costs of hibernation, was detected in the area. From 2011 to 2022, the population rapidly decreased in the northern area and increased in the southern area, completely reversing the northerly shift in population densities associated with climate change. Energy balance during hibernation is the singular link explaining the northerly shift under a changing climate and the southerly shift in response to a novel disease. Continued population persistence suggests that bats may mitigate many impacts of WNS by hibernating farther south, where insects are available longer each year.

APA, Harvard, Vancouver, ISO, and other styles

18

Frank, Craig L., April D. Davis, and Carl Herzog. "The evolution of a bat population with white-nose syndrome (WNS) reveals a shift from an epizootic to an enzootic phase." Frontiers in Zoology 16, no. 1 (2019): 40. https://doi.org/10.5281/zenodo.14819574.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: White-nose Syndrome (WNS) is a mycosis caused by a cutaneous infection with the fungus Pseudogymnoascus destructans (Pd). It produces hibernation mortality rates of 75–98% in 4 bats: Myotis lucifugus, M. septentrionalis, M. sodalis, and Perimyotis subflavus. These high mortality rates were observed during the first several years after the arrival of P. destructans at a hibernation site. Mortality is caused by a 60% decrease in torpor bout duration, which results in a premature depletion of depot fat prior to spring. Results: Little is known about the long-term effects of Pd on torpor and mortality, thus we conducted a 9-year study on M. lucifugus at 5 of the hibernation sites where Pd first appeared in North America during the winter of 2007–08. The M. lucifugus hibernating at one of these sites one year after the arrival of Pd (2008–09) had: a) a mean torpor bout duration of 7.6 d, b) no depot fat reserves by March, and c) an apparent over-winter mortality rate of 88%. The M. lucifugus hibernating at this same site 6–9 years after the arrival of Pd, in contrast, had: a) a mean torpor bout duration of 14.7 d, b) depot fat remaining in March, and c) an apparent mortality rate of 50%. The number of M. lucifugus hibernating at 2 of these sites has consistently increased since 2010 and is now more than 3.0-fold higher than the number remaining after the winter of 2008–09. Conclusions: These findings indicate that this population of M. lucifugus has evolved mechanisms to hibernate well in the presence of Pd, thus reducing over-winter mortality.

APA, Harvard, Vancouver, ISO, and other styles

19

Meier, Frauke, Leo Grosche, Christine Reusch, Volker Runkel, Schaik Jaap Van, and Gerald Kerth. "Long-term individualized monitoring of sympatric bat species reveals distinct species- and demographic differences in hibernation phenology." BMC Ecology and Evolution 22, no. 1 (2022): 7. https://doi.org/10.5281/zenodo.13443735.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Hibernation allows species to conserve energy and thereby bridge unfavorable environmental conditions. At the same time, hibernation imposes substantial ecological and physiological costs. Understanding how hibernation timing differs within and between species can provide insights into the underlying drivers of this trade-off. However, this requires individualized long-term data that are often unavailable. Here, we used automatic monitoring techniques and a reproducible analysis pipeline to assess the individualized hibernation phenology of two sympatric bat species. Our study is based on data of more than 1100 RFID-tagged Daubenton's bats (Myotis daubentonii) and Natterer's bats (Myotis nattereri) collected over seven years at a hibernaculum in Germany. We used linear mixed models to analyze species-, sex- and age-specific differences in entrance, emergence and duration of the longest continuous period spent in the hibernaculum. Results: Overall, Daubenton's bats entered the hibernaculum earlier and emerged later than Natterer's bats, resulting in a nearly twice as long hibernation duration. In both species, adult females entered earlier and emerged from hibernation later than adult males. Hibernation duration was shorter for juveniles than adults with the exception of adult male Natterer's bats whose hibernation duration was shortest of all classes. Finally, hibernation timing differed among years, but yearly variations in entrance and emergence timing were not equally shifted in both species. Conclusions: Our results suggest that even in sympatric species, and across sex and age classes, hibernation timing may be differentially affected by environmental conditions. This highlights the necessity of using individualized information when studying the impact of changing environments on hibernation phenology.

APA, Harvard, Vancouver, ISO, and other styles

20

Meier, Frauke, Leo Grosche, Christine Reusch, Volker Runkel, Schaik Jaap Van, and Gerald Kerth. "Long-term individualized monitoring of sympatric bat species reveals distinct species- and demographic differences in hibernation phenology." BMC Ecology and Evolution 22, no. 1 (2022): 7. https://doi.org/10.5281/zenodo.13443735.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Hibernation allows species to conserve energy and thereby bridge unfavorable environmental conditions. At the same time, hibernation imposes substantial ecological and physiological costs. Understanding how hibernation timing differs within and between species can provide insights into the underlying drivers of this trade-off. However, this requires individualized long-term data that are often unavailable. Here, we used automatic monitoring techniques and a reproducible analysis pipeline to assess the individualized hibernation phenology of two sympatric bat species. Our study is based on data of more than 1100 RFID-tagged Daubenton's bats (Myotis daubentonii) and Natterer's bats (Myotis nattereri) collected over seven years at a hibernaculum in Germany. We used linear mixed models to analyze species-, sex- and age-specific differences in entrance, emergence and duration of the longest continuous period spent in the hibernaculum. Results: Overall, Daubenton's bats entered the hibernaculum earlier and emerged later than Natterer's bats, resulting in a nearly twice as long hibernation duration. In both species, adult females entered earlier and emerged from hibernation later than adult males. Hibernation duration was shorter for juveniles than adults with the exception of adult male Natterer's bats whose hibernation duration was shortest of all classes. Finally, hibernation timing differed among years, but yearly variations in entrance and emergence timing were not equally shifted in both species. Conclusions: Our results suggest that even in sympatric species, and across sex and age classes, hibernation timing may be differentially affected by environmental conditions. This highlights the necessity of using individualized information when studying the impact of changing environments on hibernation phenology.

APA, Harvard, Vancouver, ISO, and other styles

21

Meier, Frauke, Leo Grosche, Christine Reusch, Volker Runkel, Schaik Jaap Van, and Gerald Kerth. "Long-term individualized monitoring of sympatric bat species reveals distinct species- and demographic differences in hibernation phenology." BMC Ecology and Evolution 22, no. 1 (2022): 7. https://doi.org/10.5281/zenodo.13443735.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Hibernation allows species to conserve energy and thereby bridge unfavorable environmental conditions. At the same time, hibernation imposes substantial ecological and physiological costs. Understanding how hibernation timing differs within and between species can provide insights into the underlying drivers of this trade-off. However, this requires individualized long-term data that are often unavailable. Here, we used automatic monitoring techniques and a reproducible analysis pipeline to assess the individualized hibernation phenology of two sympatric bat species. Our study is based on data of more than 1100 RFID-tagged Daubenton's bats (Myotis daubentonii) and Natterer's bats (Myotis nattereri) collected over seven years at a hibernaculum in Germany. We used linear mixed models to analyze species-, sex- and age-specific differences in entrance, emergence and duration of the longest continuous period spent in the hibernaculum. Results: Overall, Daubenton's bats entered the hibernaculum earlier and emerged later than Natterer's bats, resulting in a nearly twice as long hibernation duration. In both species, adult females entered earlier and emerged from hibernation later than adult males. Hibernation duration was shorter for juveniles than adults with the exception of adult male Natterer's bats whose hibernation duration was shortest of all classes. Finally, hibernation timing differed among years, but yearly variations in entrance and emergence timing were not equally shifted in both species. Conclusions: Our results suggest that even in sympatric species, and across sex and age classes, hibernation timing may be differentially affected by environmental conditions. This highlights the necessity of using individualized information when studying the impact of changing environments on hibernation phenology.

APA, Harvard, Vancouver, ISO, and other styles

22

Meier, Frauke, Leo Grosche, Christine Reusch, Volker Runkel, Schaik Jaap Van, and Gerald Kerth. "Long-term individualized monitoring of sympatric bat species reveals distinct species- and demographic differences in hibernation phenology." BMC Ecology and Evolution 22, no. 1 (2022): 7. https://doi.org/10.5281/zenodo.13443735.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Hibernation allows species to conserve energy and thereby bridge unfavorable environmental conditions. At the same time, hibernation imposes substantial ecological and physiological costs. Understanding how hibernation timing differs within and between species can provide insights into the underlying drivers of this trade-off. However, this requires individualized long-term data that are often unavailable. Here, we used automatic monitoring techniques and a reproducible analysis pipeline to assess the individualized hibernation phenology of two sympatric bat species. Our study is based on data of more than 1100 RFID-tagged Daubenton's bats (Myotis daubentonii) and Natterer's bats (Myotis nattereri) collected over seven years at a hibernaculum in Germany. We used linear mixed models to analyze species-, sex- and age-specific differences in entrance, emergence and duration of the longest continuous period spent in the hibernaculum. Results: Overall, Daubenton's bats entered the hibernaculum earlier and emerged later than Natterer's bats, resulting in a nearly twice as long hibernation duration. In both species, adult females entered earlier and emerged from hibernation later than adult males. Hibernation duration was shorter for juveniles than adults with the exception of adult male Natterer's bats whose hibernation duration was shortest of all classes. Finally, hibernation timing differed among years, but yearly variations in entrance and emergence timing were not equally shifted in both species. Conclusions: Our results suggest that even in sympatric species, and across sex and age classes, hibernation timing may be differentially affected by environmental conditions. This highlights the necessity of using individualized information when studying the impact of changing environments on hibernation phenology.

APA, Harvard, Vancouver, ISO, and other styles

23

Goldberg, Amanda R., and Courtney J. Conway. "Hibernation behavior of a federally threatened ground squirrel: climate change and habitat selection implications." Journal of Mammalogy 102, no. 2 (2021): 574–87. http://dx.doi.org/10.1093/jmammal/gyab021.

Full text

Abstract:

Abstract Hibernation is an adaptation to survive periods of stress, from food limitation or harsh thermal conditions. A key question in contemporary ecology is whether rare, range-restricted species can change their behavior in response to climate change (i.e., through behavioral plasticity). The northern Idaho ground squirrel, Urocitellus brunneus (A. H. Howell, 1928), is a federally threatened species that hibernates for approximately 8 months per year within the bounds of its small range in central Idaho, USA. Changes in temperature, snow accumulation, and summer precipitation, all brought about as a result of climate change, may reduce survival or fecundity of northern Idaho ground squirrels if they cannot adapt to these climate changes. Hibernating species can respond to climate-change-induced thermal challenges in two ways: change their hibernation physiology and behavior (i.e., emergence date or number of torpor bouts) or alter their environment (i.e., change hibernacula depth or location). We explored a suite of intrinsic and extrinsic factors to document the extent to which they influenced hibernation behavior of northern Idaho ground squirrels. Emergence date was positively associated with snowpack and negatively associated with mean winter temperature. Mean minimum skin temperature was negatively associated with canopy closure and slope of a squirrel’s hibernaculum. Duration of the heterothermal period, number of euthermic bouts, and total time spent euthermic were positively associated with body mass. Immergence date and duration of the longest torpor bout were negatively associated with body mass. Warmer temperatures and less snow accumulation in the winter—caused by climate change—likely will cause altered emergence dates. Our results suggest that any future climate-induced changes in snowfall, ambient temperature, food availability, or habitat likely will impact survival of this rare ground squirrel, because such changes will cause changes in hibernation behavior, percent mass loss during hibernation, and duration of the active season when small mammals are more susceptible to predation.

APA, Harvard, Vancouver, ISO, and other styles

24

Chunkov, M. M., D. K. Omarova, A. V. Surov, K. Z. Omarov, and N. Yu Feоktistova. "Body temperature dynamics of the Ciscaucasian hamster (Mesocricetus raddei) (Cricetidae, Rodentia) during hibernation." Povolzhskiy Journal of Ecology, no. 1 (March 24, 2024): 79–97. http://dx.doi.org/10.35885/1684-7318-2024-1-79-97.

Full text

Abstract:

The body temperature dynamics of the Ciscaucasian hamster (Mesocricetus raddei) during winter hibernation was studied in semi-natural conditions (a mesh cage buried in the ground, where animals could dig burrows) in mountainous Dagestan. Thermologgers were implanted intraperitoneally to seven adult animals (three females and four males) to record body temperature at 30 min intervals. All individuals successfully overwintered and exhibited regular episodes of hypothermia. The average of total duration of one heterothermia period was 192±6.8 days, that of one hypothermia and normothermia episode was 15 5.3±6.2 h and 16.5±1.2 h, respectively. The minimum body temperature reached +0.5°C. It has been shown that the body temperature and the duration of hypothermia episodes are negatively correlated with the temperature inside the burrow. Adaptive hibernation mechanisms of the Ciscaucasian hamster and other hibernating mammalian species are discussed.

APA, Harvard, Vancouver, ISO, and other styles

25

Brack Jr., Virgil, and John W. Twente. "The duration of the period of hibernation of three species of vespertilionid bats. I. Field studies." Canadian Journal of Zoology 63, no. 12 (1985): 2952–54. http://dx.doi.org/10.1139/z85-442.

Full text

Abstract:

The durations of the periods of hibernation of the big brown bat (Eptesicus fuscus), little brown bat (Myotis lucifugus), and eastern pipistrelle (Pipistrellus subflavus) under natural conditions were determined by following intracave movements through two winter seasons in two Missouri caves. Average durations of periods of hibernation were similar for all three species (10–20 days) over a range of temperatures. Maximum durations of periods of hibernation determined were as follows: E. fuscus, 72 days; P. subflavus, 111 days (?); M. lucifugus, 83 days. Variability in the durations of the period of hibernation was much greater for P. subflavus and may be attributable to a lack of movement after arousal or the inability of the observer to discern movement between periods of hibernation. The frequency of arousal was determined to be statistically temperature dependent for M. lucifugus, but not for E. fuscus or P. subflavus, probably because of insufficient data.

APA, Harvard, Vancouver, ISO, and other styles

26

HAEUSSLER, E. M., J. PIZÁ, D. SCHMERA, and B. BAUR. "Intensity of parasitic mite infection decreases with hibernation duration of the host snail." Parasitology 139, no. 8 (2012): 1038–44. http://dx.doi.org/10.1017/s0031182012000327.

Full text

Abstract:

SUMMARYTemperature can be a limiting factor on parasite development. Riccardoella limacum, a haematophagous mite, lives in the mantle cavity of helicid land snails. The prevalence of infection by R. limacum in populations of the land snail Arianta arbustorum is highly variable (0–78%) in Switzerland. However, parasitic mites do not occur in host populations at altitudes of 1290 m or higher. It has been hypothesized that the host's hibernation period might be too long at high elevations for mites and their eggs to survive. To test this hypothesis, we experimentally infected snails and allowed them to hibernate at 4°C for periods of 4–7 months. Winter survival of host snails was negatively affected by R. limacum. The intensity of mite infection decreased with increasing hibernation duration. Another experiment with shorter recording intervals revealed that mites do not leave the host when it buries in the soil at the beginning of hibernation. The number of mites decreased after 24 days of hibernation, whereas the number of eggs attached to the lung tissue remained constant throughout hibernation. Thus, R. limacum survives the winter in the egg stage in the host. Low temperature at high altitudes may limit the occurrence of R. limacum.

APA, Harvard, Vancouver, ISO, and other styles

27

Martínková, Natália, Stuart J. E. Baird, Vlastislav Káňa, and Jan Zima. "Bat population recoveries give insight into clustering strategies during hibernation." Frontiers in Zoology 17, no. 1 (2020): 26. https://doi.org/10.5281/zenodo.13471038.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Behaviour during hibernation contributes to energy conservation in winter. Hibernating bats select roosts with respect to physiological and environmental stressors, available local microclimate and species-specific requirements. Results: We found that, in the period between 1977 and 2018, hibernating Myotis myotis and Rhinolophus hipposideros bats showed exponential population growth. The growth rates, corrected for local winter seasonal severity and winter duration, were equal to 10 and 13%, respectively. While R. hipposideros only utilised the thermally stable and, at survey time, warmer corridors in the hibernaculum, an increasing proportion of M. myotis roosted in the thermally stable corridors as their abundance increased. About 14% of all hibernating M. myotis displayed solitary roosting, irrespective of other covariates. Those bats that clustered together formed progressively larger clusters with increasing abundance, particularly in cold corridors. We found no statistically significant relationship for clustering behaviour or cluster size with winter severity or winter duration. Conclusions: Abundance of hibernating bats is increasing in Central Europe. As the number of M. myotis bats increases, thermally unstable corridors become saturated with large clusters and the animals begin to roost deeper underground.

APA, Harvard, Vancouver, ISO, and other styles

28

Martínková, Natália, Stuart J. E. Baird, Vlastislav Káňa, and Jan Zima. "Bat population recoveries give insight into clustering strategies during hibernation." Frontiers in Zoology 17, no. 1 (2020): 26. https://doi.org/10.5281/zenodo.13471038.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Behaviour during hibernation contributes to energy conservation in winter. Hibernating bats select roosts with respect to physiological and environmental stressors, available local microclimate and species-specific requirements. Results: We found that, in the period between 1977 and 2018, hibernating Myotis myotis and Rhinolophus hipposideros bats showed exponential population growth. The growth rates, corrected for local winter seasonal severity and winter duration, were equal to 10 and 13%, respectively. While R. hipposideros only utilised the thermally stable and, at survey time, warmer corridors in the hibernaculum, an increasing proportion of M. myotis roosted in the thermally stable corridors as their abundance increased. About 14% of all hibernating M. myotis displayed solitary roosting, irrespective of other covariates. Those bats that clustered together formed progressively larger clusters with increasing abundance, particularly in cold corridors. We found no statistically significant relationship for clustering behaviour or cluster size with winter severity or winter duration. Conclusions: Abundance of hibernating bats is increasing in Central Europe. As the number of M. myotis bats increases, thermally unstable corridors become saturated with large clusters and the animals begin to roost deeper underground.

APA, Harvard, Vancouver, ISO, and other styles

29

Martínková, Natália, Stuart J. E. Baird, Vlastislav Káňa, and Jan Zima. "Bat population recoveries give insight into clustering strategies during hibernation." Frontiers in Zoology 17, no. 1 (2020): 26. https://doi.org/10.5281/zenodo.13471038.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Behaviour during hibernation contributes to energy conservation in winter. Hibernating bats select roosts with respect to physiological and environmental stressors, available local microclimate and species-specific requirements. Results: We found that, in the period between 1977 and 2018, hibernating Myotis myotis and Rhinolophus hipposideros bats showed exponential population growth. The growth rates, corrected for local winter seasonal severity and winter duration, were equal to 10 and 13%, respectively. While R. hipposideros only utilised the thermally stable and, at survey time, warmer corridors in the hibernaculum, an increasing proportion of M. myotis roosted in the thermally stable corridors as their abundance increased. About 14% of all hibernating M. myotis displayed solitary roosting, irrespective of other covariates. Those bats that clustered together formed progressively larger clusters with increasing abundance, particularly in cold corridors. We found no statistically significant relationship for clustering behaviour or cluster size with winter severity or winter duration. Conclusions: Abundance of hibernating bats is increasing in Central Europe. As the number of M. myotis bats increases, thermally unstable corridors become saturated with large clusters and the animals begin to roost deeper underground.

APA, Harvard, Vancouver, ISO, and other styles

30

Martínková, Natália, Stuart J. E. Baird, Vlastislav Káňa, and Jan Zima. "Bat population recoveries give insight into clustering strategies during hibernation." Frontiers in Zoology 17, no. 1 (2020): 26. https://doi.org/10.5281/zenodo.13471038.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Background: Behaviour during hibernation contributes to energy conservation in winter. Hibernating bats select roosts with respect to physiological and environmental stressors, available local microclimate and species-specific requirements. Results: We found that, in the period between 1977 and 2018, hibernating Myotis myotis and Rhinolophus hipposideros bats showed exponential population growth. The growth rates, corrected for local winter seasonal severity and winter duration, were equal to 10 and 13%, respectively. While R. hipposideros only utilised the thermally stable and, at survey time, warmer corridors in the hibernaculum, an increasing proportion of M. myotis roosted in the thermally stable corridors as their abundance increased. About 14% of all hibernating M. myotis displayed solitary roosting, irrespective of other covariates. Those bats that clustered together formed progressively larger clusters with increasing abundance, particularly in cold corridors. We found no statistically significant relationship for clustering behaviour or cluster size with winter severity or winter duration. Conclusions: Abundance of hibernating bats is increasing in Central Europe. As the number of M. myotis bats increases, thermally unstable corridors become saturated with large clusters and the animals begin to roost deeper underground.

APA, Harvard, Vancouver, ISO, and other styles

31

Şereflişan, Hülya, and Önder Duysak. "Hibernation Period in Some Land Snail Species (Gastropoda: Helicidae): Epiphragmal Structure and Hypometabolic Behaviors." Turkish Journal of Agriculture - Food Science and Technology 9, no. 1 (2021): 166–71. http://dx.doi.org/10.24925/turjaf.v9i1.166-171.3777.

Full text

Abstract:

In this study, the hypometabolism behavior, epiphragm formation process, and the mineral composition of the epiphragmal structure of the Helix pomacella, Eobania vermiculata, Helix melanostoma, and Helix asemnis land snails were investigated during the hibernation period. 100 snails selected among mature individuals, 25 from each species, were collected from nature for the research. The snails were placed in four 50x50x5 cm pans containing 20-cm-deep humus soil. Snails were fed with lettuce by free feeding until the hibernation period. Hypometabolism behavior of snails that had hibernated between November and December 2018, and January and February 2019 were examined as entering the hibernation stage, hibernation stage, and leaving the hibernation stage. The ionic concentration (Calcium, Iron, and Phosphorus) of the epiphragm layer formed during the hibernation process was analyzed, its formation duration, and its degradation at the end of the hibernation period were examined. In the study, it was determined that the weight before hibernation reduced by 18-22% in all examined species (H. pomacella, E. vermiculata, H. melanostoma, and H. asemnis). The highest values in terms of epiphragm formation duration (19±0.30 days), weight (0.41±0.26 g), and thickness (0.310±0.22 mm) were determined in H. asemnis. In terms of the ionic concentration, the highest Calcium level was determined in H. asemnis (29.96±0.12 mg/g) while the highest Phosphorus level (4.02±0.20 mg/g) was determined in E. vermiculata, and the highest Iron content was found in H. pomacella (19.50±0.33 mg/g). The degradation duration of the epiphragm layer at the end of hibernation was determined the longest in E. vermiculata (7 days) whereas the shortest in H. pomacella (3 days). As a result of the present research, it was seen that the epiphragm layer is important for snails in terms of a sustainable life cycle and that the ecological tolerances of snails depend on the epiphragmal structure.

APA, Harvard, Vancouver, ISO, and other styles

32

Ruf, Thomas, and Walter Arnold. "Effects of polyunsaturated fatty acids on hibernation and torpor: a review and hypothesis." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 294, no. 3 (2008): R1044—R1052. http://dx.doi.org/10.1152/ajpregu.00688.2007.

Full text

Abstract:

Polyunsaturated fatty acids (PUFAs) can have strong effects on hibernation and daily torpor in mammals. High dietary PUFA contents were found to increase proneness for torpor, decrease body temperatures, prolong torpor bout duration, and attenuate hibernation mass loss. The mechanism by which PUFAs enhance torpor and hibernation is unknown, however. On the basis of a review of the literature, and on reexamining our own data on alpine marmots, we propose that effects on hibernation are not due to PUFAs in general, but to shifts in the ratio of n-6 PUFAs to n-3 PUFAs in membrane phospholipids. Specifically, high ratios of n-6 to n-3 PUFAs increase the activity of the Ca2+-Mg2+ pump in the sarcoplasmic reticulum of the heart (SERCA) and counteract Q10 effects on SERCA activity at low tissue temperatures. Therefore, high n-6 to n-3 PUFA ratios in cardiac myocyte membranes appear to protect the hibernating heart from arrhythmia, which in hypothermic nonhibernators is caused by massive increases in cytosolic Ca2+. The resulting reduced risk of cardiac arrest during hypothermia may explain why increased dietary uptake of n-6 PUFAs, but not of n-3 PUFAs, can strongly enhance the propensity for hibernation, and allows heterotherms to reach lower body temperatures, with associated increased energy savings. Therefore, at least for herbivorous hibernators, such as marmots, linoleic acid (C18:2 n-6)—the dietary source of all n-6 PUFAs—appears to represent a crucial and limited resource in natural environments.

APA, Harvard, Vancouver, ISO, and other styles

33

Arant, Ryan J., Marisa S. Goo, Phoebe D. Gill, et al. "Decreasing temperature shifts hippocampal function from memory formation to modulation of hibernation bout duration in Syrian hamsters." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 301, no. 2 (2011): R438—R447. http://dx.doi.org/10.1152/ajpregu.00016.2011.

Full text

Abstract:

Previous studies in hibernating species have characterized two forms of neural plasticity in the hippocampus, long-term potentiation (LTP) and its reversal, depotentiation, but not de novo long-term depression (LTD), which is also associated with memory formation. Studies have also shown that histamine injected into the hippocampus prolonged hibernation bout duration. However, spillover into the ventricles may have affected brain stem regions, not the hippocampus. Here, we tested the hypothesis that decreased brain temperature shifts the major function of the hippocampus in the Syrian hamster ( Mesocricetus auratus) from one of memory formation (via LTP, depotentiation, and de novo LTD) to increasing hibernation bout duration. We found reduced evoked responses in hippocampal CA1 pyramidal neurons following low-frequency stimulation in young (<30 days old) and adult (>60 days old) hamsters, indicating that de novo LTD was generated in hippocampal slices from both pups and adults at temperatures >20°C. However, at temperatures below 20°C, synchronization of neural assemblies (a requirement for LTD generation) was markedly degraded, implying that de novo LTD cannot be generated in hibernating hamsters. Nonetheless, even at temperatures below 16°C, pyramidal neurons could still generate action potentials that may traverse a neural pathway, suppressing the ascending arousal system (ARS). In addition, histamine increased the excitability of these pyramidal cells. Taken together, these findings are consistent with the hypothesis that hippocampal circuits remain operational at low brain temperatures in Syrian hamsters and suppress the ARS to prolong bout duration, even though memory formation is muted at these low temperatures.

APA, Harvard, Vancouver, ISO, and other styles

34

Broome, LS, and F. Geiser. "Hibernation in Free-Living Mountain Pygmy-Possums, Burramys Parvus (Marsupialia, Burramyidae)." Australian Journal of Zoology 43, no. 4 (1995): 373. http://dx.doi.org/10.1071/zo9950373.

Full text

Abstract:

The long-term pattern of hibernation was studied in free-living mountain pygmy-possums, Burramys parvus, using temperature-sensitive radio-collars. Most males and females began to hibernate in early June within one week of their release. Hibernation was interrupted by spontaneous arousals that were followed by short normothermic periods and re-entry into torpor. The duration of multiday torpor bouts averaged 8 . 0 days (range 3-17 days) and arousal periods averaged 19 . 1 h. Single-day torpor bouts were observed occasionally. The duration of torpor bouts lengthened with the progress of the hibernation season and normothermic periods became shorter. The pattern of hibernation in free-living B. parvus was similar to that of captive individuals maintained under temperature regimes that were similar to those in the wild.

APA, Harvard, Vancouver, ISO, and other styles

35

Kauffman, Alexander S., Matthew J. Paul, and Irving Zucker. "Increased heat loss affects hibernation in golden-mantled ground squirrels." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 287, no. 1 (2004): R167—R173. http://dx.doi.org/10.1152/ajpregu.00670.2003.

Full text

Abstract:

During hibernation at ambient temperatures (Ta) above 0°C, rodents typically maintain body temperature (Tb) ∼1°C above Ta, reduce metabolic rate, and suspend or substantially reduce many physiological functions. We tested the extent to which the presence of an insulative pelage affects hibernation. Tb was recorded telemetrically in golden-mantled ground squirrels ( Spermophilus lateralis) housed at a Ta of 5°C; food intake and body mass were measured at regular intervals throughout the hibernation season and after the terminal arousal. Animals were subjected to complete removal of the dorsal fur or a control procedure after they had been in hibernation for 3–4 wk. Shaved squirrels continued to hibernate with little or no change in minimum Tb, bout duration, duration of periodic normothermic bouts, and food intake during normothermia. Rates of rewarming from torpor were, however, significantly slower in shaved squirrels, and rates of body mass loss were significantly higher, indicating increased depletion of white adipose energy stores. An insulative pelage evidently conserves energy over the course of the hibernation season by decreasing body heat loss and reducing energy expenditure during periodic arousals from torpor and subsequent intervals of normothermia. This prolongs the hibernation season by several weeks, thereby eliminating the debilitating consequences associated with premature emergence from hibernation.

APA, Harvard, Vancouver, ISO, and other styles

36

Muise, Kristina A., Yvonne A. Dzal, Quinn E. Fletcher, and Craig K. R. Willis. "Hibernating female big brown bats (Eptesicus fuscus) adjust huddling and drinking behaviour, but not arousal frequency, in response to low humidity." Journal of Experimental Biology 227, no. 5 (2024): jeb246699. https://doi.org/10.5281/zenodo.13442333.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Many mammals hibernate during winter, reducing energy expenditure via bouts of torpor. The majority of a hibernator's energy reserves are used to fuel brief, but costly, arousals from torpor. Although arousals likely serve multiple functions, an important one is to restore water stores depleted during torpor. Many hibernating bat species require high humidity, presumably to reduce torpid water loss, but big brown bats (Eptesicus fuscus) appear tolerant of a wide humidity range. We tested the hypothesis that hibernating female E. fuscus use behavioural flexibility during torpor and arousals to maintain water balance and reduce energy expenditure. We predicted: (1) E. fuscus hibernating in dry conditions would exhibit more compact huddles during torpor and drink more frequently than bats in high humidity conditions; and (2) the frequency and duration of torpor bouts and arousals, and thus total loss of body mass would not differ between bats in the two environments. We housed hibernating E. fuscus in temperature- and humidity-controlled incubators at 50% or 98% relative humidity (8°C, 110 days). Bats in the dry environment maintained a more compact huddle during torpor and drank more frequently during arousals. Bats in the two environments had a similar number of arousals, but arousal duration was shorter in the dry environment. However, total loss of body mass over hibernation did not differ between treatments, indicating that the two groups used similar amounts of energy. Our results suggest that behavioural flexibility allows hibernating E. fuscus to maintain water balance and reduce energy costs across a wide range of hibernation humidities.

APA, Harvard, Vancouver, ISO, and other styles

37

Muise, Kristina A., Yvonne A. Dzal, Quinn E. Fletcher, and Craig K. R. Willis. "Hibernating female big brown bats (Eptesicus fuscus) adjust huddling and drinking behaviour, but not arousal frequency, in response to low humidity." Journal of Experimental Biology 227, no. 5 (2024): jeb246699. https://doi.org/10.5281/zenodo.13442333.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Many mammals hibernate during winter, reducing energy expenditure via bouts of torpor. The majority of a hibernator's energy reserves are used to fuel brief, but costly, arousals from torpor. Although arousals likely serve multiple functions, an important one is to restore water stores depleted during torpor. Many hibernating bat species require high humidity, presumably to reduce torpid water loss, but big brown bats (Eptesicus fuscus) appear tolerant of a wide humidity range. We tested the hypothesis that hibernating female E. fuscus use behavioural flexibility during torpor and arousals to maintain water balance and reduce energy expenditure. We predicted: (1) E. fuscus hibernating in dry conditions would exhibit more compact huddles during torpor and drink more frequently than bats in high humidity conditions; and (2) the frequency and duration of torpor bouts and arousals, and thus total loss of body mass would not differ between bats in the two environments. We housed hibernating E. fuscus in temperature- and humidity-controlled incubators at 50% or 98% relative humidity (8°C, 110 days). Bats in the dry environment maintained a more compact huddle during torpor and drank more frequently during arousals. Bats in the two environments had a similar number of arousals, but arousal duration was shorter in the dry environment. However, total loss of body mass over hibernation did not differ between treatments, indicating that the two groups used similar amounts of energy. Our results suggest that behavioural flexibility allows hibernating E. fuscus to maintain water balance and reduce energy costs across a wide range of hibernation humidities.

APA, Harvard, Vancouver, ISO, and other styles

38

Muise, Kristina A., Yvonne A. Dzal, Quinn E. Fletcher, and Craig K. R. Willis. "Hibernating female big brown bats (Eptesicus fuscus) adjust huddling and drinking behaviour, but not arousal frequency, in response to low humidity." Journal of Experimental Biology 227, no. 5 (2024): jeb246699. https://doi.org/10.5281/zenodo.13442333.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Many mammals hibernate during winter, reducing energy expenditure via bouts of torpor. The majority of a hibernator's energy reserves are used to fuel brief, but costly, arousals from torpor. Although arousals likely serve multiple functions, an important one is to restore water stores depleted during torpor. Many hibernating bat species require high humidity, presumably to reduce torpid water loss, but big brown bats (Eptesicus fuscus) appear tolerant of a wide humidity range. We tested the hypothesis that hibernating female E. fuscus use behavioural flexibility during torpor and arousals to maintain water balance and reduce energy expenditure. We predicted: (1) E. fuscus hibernating in dry conditions would exhibit more compact huddles during torpor and drink more frequently than bats in high humidity conditions; and (2) the frequency and duration of torpor bouts and arousals, and thus total loss of body mass would not differ between bats in the two environments. We housed hibernating E. fuscus in temperature- and humidity-controlled incubators at 50% or 98% relative humidity (8°C, 110 days). Bats in the dry environment maintained a more compact huddle during torpor and drank more frequently during arousals. Bats in the two environments had a similar number of arousals, but arousal duration was shorter in the dry environment. However, total loss of body mass over hibernation did not differ between treatments, indicating that the two groups used similar amounts of energy. Our results suggest that behavioural flexibility allows hibernating E. fuscus to maintain water balance and reduce energy costs across a wide range of hibernation humidities.

APA, Harvard, Vancouver, ISO, and other styles

39

Muise, Kristina A., Yvonne A. Dzal, Quinn E. Fletcher, and Craig K. R. Willis. "Hibernating female big brown bats (Eptesicus fuscus) adjust huddling and drinking behaviour, but not arousal frequency, in response to low humidity." Journal of Experimental Biology 227, no. 5 (2024): jeb246699. https://doi.org/10.5281/zenodo.13442333.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Many mammals hibernate during winter, reducing energy expenditure via bouts of torpor. The majority of a hibernator's energy reserves are used to fuel brief, but costly, arousals from torpor. Although arousals likely serve multiple functions, an important one is to restore water stores depleted during torpor. Many hibernating bat species require high humidity, presumably to reduce torpid water loss, but big brown bats (Eptesicus fuscus) appear tolerant of a wide humidity range. We tested the hypothesis that hibernating female E. fuscus use behavioural flexibility during torpor and arousals to maintain water balance and reduce energy expenditure. We predicted: (1) E. fuscus hibernating in dry conditions would exhibit more compact huddles during torpor and drink more frequently than bats in high humidity conditions; and (2) the frequency and duration of torpor bouts and arousals, and thus total loss of body mass would not differ between bats in the two environments. We housed hibernating E. fuscus in temperature- and humidity-controlled incubators at 50% or 98% relative humidity (8°C, 110 days). Bats in the dry environment maintained a more compact huddle during torpor and drank more frequently during arousals. Bats in the two environments had a similar number of arousals, but arousal duration was shorter in the dry environment. However, total loss of body mass over hibernation did not differ between treatments, indicating that the two groups used similar amounts of energy. Our results suggest that behavioural flexibility allows hibernating E. fuscus to maintain water balance and reduce energy costs across a wide range of hibernation humidities.

APA, Harvard, Vancouver, ISO, and other styles

40

Costanzo, Jon P. "Effects of humidity, temperature, and submergence behavior on survivorship and energy use in hibernating garter snakes, Thamnophis sirtalis." Canadian Journal of Zoology 67, no. 10 (1989): 2486–92. http://dx.doi.org/10.1139/z89-351.

Full text

Abstract:

Desiccation is likely an important factor influencing winter mortality rates of terrestrially hibernating reptiles; however, this notion has not been rigorously tested. Groups of eastern garter snakes (Thamnophis sirtalis sirtalis) were matched for size and subsequently exposed to simulated hibernative conditions (5 or 12 °C, under different humidity regimes) during winter, for 165 days or until all group members expired. As garter snakes in some dens submerge during natural hibernation, an additional group was maintained in water at 5 °C. Snakes kept in air dehydrated and died (body water contents at death ranged from 62.1 to 67.8% of lean fresh mass), whereas snakes kept in water remained hydrated (median, 75.2%) and survived. Survival duration of air hibernators was inversely related to rate of mass loss, which in turn was strongly influenced by ambient humidity and temperature. Dehydration accounted for most of the mass lost in all air hibernators; however, owing to higher rates of nutrient consumption, mass loss was significantly greater in snakes kept at 12 °C (36%) than in snakes kept at 5 °C (29%). Changes in fat body and liver masses showed that snakes kept in air at 12 °C used the most energy whereas those kept in water at 5 °C used the least. Submerged hibernation behavior has significant survival value because under these conditions snakes remain hydrated during winter. Also, because submerged snakes conserve more stored energy during winter, their reproductive success may be enhanced when mating activities resume in early spring.

APA, Harvard, Vancouver, ISO, and other styles

41

South, Kathryn E., Kelly Haynes, and Angus C. Jackson. "Hibernation Patterns of the European Hedgehog, Erinaceus europaeus, at a Cornish Rescue Centre." Animals 10, no. 8 (2020): 1418. http://dx.doi.org/10.3390/ani10081418.

Full text

Abstract:

The European hedgehog, Erinaceus europaeus, is frequently admitted to rescue centres in the UK. With many overwintering in captivity, there is cause to investigate hibernation patterns in order to inform and improve husbandry and monitoring protocols. Thirty-five hedgehogs were studied over two winters. Weight change during hibernation for the first winter was used to test for effects of disturbance on different aspects of hibernation, including total duration, frequency and duration of spontaneous arousals. There was no significant difference between the two winters for any of the four aspects studied. Significant positive correlations demonstrated that weight-loss increased with the duration of the hibernation period and with percent of nights spent asleep, but not with the number of arousal events. Thus, weight-loss appears more strongly associated with the proportion of time spent asleep than with the number of arousal events. This was surprising given the assumed energetic expense of repeated arousal and was potentially due to availability of food during arousals. In contrast with previous studies, larger hedgehogs lost less weight per day than did smaller hedgehogs. They also woke up more often (i.e., had more opportunities to feed), which may explain the unexpected pattern of weight-loss. Hibernatory behaviour in captivity differs from that in the wild, likely because of non-natural conditions in hutches and the immediate availability of food. This study provides a basis for further research into the monitoring and husbandry of hedgehogs such that it can be adapted for each individual according to pre-hibernation weight and behaviour during hibernation.

APA, Harvard, Vancouver, ISO, and other styles

42

Lee, T. M., K. Pelz, P. Licht, and I. Zucker. "Testosterone influences hibernation in golden-mantled ground squirrels." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 259, no. 4 (1990): R760—R767. http://dx.doi.org/10.1152/ajpregu.1990.259.4.r760.

Full text

Abstract:

At different phases of the hibernation season, castrated male golden-mantled ground squirrels were implanted with capsules that either were filled with testosterone (T) or left empty (blank). Blank-treated animals hibernated normally when housed at 5 degrees C. Entry into hibernation was prevented in the majority of squirrels treated with T several days before the initial cold challenge. T concentrations that inhibited torpor (greater than 1.2 ng/ml) were comparable with those of intact males at the end of the hibernation season. In some squirrels, moderate T concentrations were compatible with hibernation, but torpor bout duration was shorter than normal. The inhibitory effect of T on hibernation did not appear to require aromatization of T to estradiol. We suggest that a steroid-independent mechanism triggers arousal from hibernation and that T-dependent processes determine whether hibernation is resumed at the end of an arousal period.

APA, Harvard, Vancouver, ISO, and other styles

43

Stanton, T. L., J. C. Daley, and S. K. Salzman. "Prolongation of hibernation bout duration by continuous intracerebroventricular infusion of melatonin in hibernating ground squirrels." Brain Research 413, no. 2 (1987): 350–55. http://dx.doi.org/10.1016/0006-8993(87)91027-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Humphries, Murray M., Donald W. Thomas, and Donald L. Kramer. "The role of energy availability in Mammalian hibernation: a cost-benefit approach." Physiological and biochemical zoology : PBZ 76, no. 2 (2003): 165–79. https://doi.org/10.5281/zenodo.13525491.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation is widely regarded as an adaptation to seasonal energy shortage, but the actual influence of energy availability on hibernation patterns is rarely considered. Here we review literature on the costs and benefits of torpor expression to examine the influence that energy may have on hibernation patterns. We first establish that the dichotomy between food- and fat-storing hibernators coincides with differences in diet rather than body size and show that small or large species pursuing either strategy have considerable potential scope in the amount of torpor needed to survive winter. Torpor expression provides substantial energy savings, which increase the chance of surviving a period of food shortage and emerging with residual energy for early spring reproduction. However, all hibernating mammals periodically arouse to normal body temperatures during hibernation. The function of these arousals has long been speculated to involve recovery from physiological costs accumulated during metabolic depression, and recent physiological studies indicate these costs may include oxidative stress, reduced immunocompetence, and perhaps neuronal tissue damage. Using an optimality approach, we suggest that trade-offs between the benefits of energy conservation and the physiological costs of metabolic depression can explain both why hibernators periodically arouse from torpor and why they should use available energy to minimize the depth and duration of their torpor bouts. On the basis of these trade-offs, we derive a series of testable predictions concerning the relationship between energy availability and torpor expression. We conclude by reviewing the empirical support for these predictions and suggesting new avenues for research on the role of energy availability in mammalian hibernation.

APA, Harvard, Vancouver, ISO, and other styles

45

Humphries, Murray M., Donald W. Thomas, and Donald L. Kramer. "The role of energy availability in Mammalian hibernation: a cost-benefit approach." Physiological and biochemical zoology : PBZ 76, no. 2 (2003): 165–79. https://doi.org/10.5281/zenodo.13525491.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation is widely regarded as an adaptation to seasonal energy shortage, but the actual influence of energy availability on hibernation patterns is rarely considered. Here we review literature on the costs and benefits of torpor expression to examine the influence that energy may have on hibernation patterns. We first establish that the dichotomy between food- and fat-storing hibernators coincides with differences in diet rather than body size and show that small or large species pursuing either strategy have considerable potential scope in the amount of torpor needed to survive winter. Torpor expression provides substantial energy savings, which increase the chance of surviving a period of food shortage and emerging with residual energy for early spring reproduction. However, all hibernating mammals periodically arouse to normal body temperatures during hibernation. The function of these arousals has long been speculated to involve recovery from physiological costs accumulated during metabolic depression, and recent physiological studies indicate these costs may include oxidative stress, reduced immunocompetence, and perhaps neuronal tissue damage. Using an optimality approach, we suggest that trade-offs between the benefits of energy conservation and the physiological costs of metabolic depression can explain both why hibernators periodically arouse from torpor and why they should use available energy to minimize the depth and duration of their torpor bouts. On the basis of these trade-offs, we derive a series of testable predictions concerning the relationship between energy availability and torpor expression. We conclude by reviewing the empirical support for these predictions and suggesting new avenues for research on the role of energy availability in mammalian hibernation.

APA, Harvard, Vancouver, ISO, and other styles

46

Humphries, Murray M., Donald W. Thomas, and Donald L. Kramer. "The role of energy availability in Mammalian hibernation: a cost-benefit approach." Physiological and biochemical zoology : PBZ 76, no. 2 (2003): 165–79. https://doi.org/10.5281/zenodo.13525491.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation is widely regarded as an adaptation to seasonal energy shortage, but the actual influence of energy availability on hibernation patterns is rarely considered. Here we review literature on the costs and benefits of torpor expression to examine the influence that energy may have on hibernation patterns. We first establish that the dichotomy between food- and fat-storing hibernators coincides with differences in diet rather than body size and show that small or large species pursuing either strategy have considerable potential scope in the amount of torpor needed to survive winter. Torpor expression provides substantial energy savings, which increase the chance of surviving a period of food shortage and emerging with residual energy for early spring reproduction. However, all hibernating mammals periodically arouse to normal body temperatures during hibernation. The function of these arousals has long been speculated to involve recovery from physiological costs accumulated during metabolic depression, and recent physiological studies indicate these costs may include oxidative stress, reduced immunocompetence, and perhaps neuronal tissue damage. Using an optimality approach, we suggest that trade-offs between the benefits of energy conservation and the physiological costs of metabolic depression can explain both why hibernators periodically arouse from torpor and why they should use available energy to minimize the depth and duration of their torpor bouts. On the basis of these trade-offs, we derive a series of testable predictions concerning the relationship between energy availability and torpor expression. We conclude by reviewing the empirical support for these predictions and suggesting new avenues for research on the role of energy availability in mammalian hibernation.

APA, Harvard, Vancouver, ISO, and other styles

47

Humphries, Murray M., Donald W. Thomas, and Donald L. Kramer. "The role of energy availability in Mammalian hibernation: a cost-benefit approach." Physiological and biochemical zoology : PBZ 76, no. 2 (2003): 165–79. https://doi.org/10.5281/zenodo.13525491.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Hibernation is widely regarded as an adaptation to seasonal energy shortage, but the actual influence of energy availability on hibernation patterns is rarely considered. Here we review literature on the costs and benefits of torpor expression to examine the influence that energy may have on hibernation patterns. We first establish that the dichotomy between food- and fat-storing hibernators coincides with differences in diet rather than body size and show that small or large species pursuing either strategy have considerable potential scope in the amount of torpor needed to survive winter. Torpor expression provides substantial energy savings, which increase the chance of surviving a period of food shortage and emerging with residual energy for early spring reproduction. However, all hibernating mammals periodically arouse to normal body temperatures during hibernation. The function of these arousals has long been speculated to involve recovery from physiological costs accumulated during metabolic depression, and recent physiological studies indicate these costs may include oxidative stress, reduced immunocompetence, and perhaps neuronal tissue damage. Using an optimality approach, we suggest that trade-offs between the benefits of energy conservation and the physiological costs of metabolic depression can explain both why hibernators periodically arouse from torpor and why they should use available energy to minimize the depth and duration of their torpor bouts. On the basis of these trade-offs, we derive a series of testable predictions concerning the relationship between energy availability and torpor expression. We conclude by reviewing the empirical support for these predictions and suggesting new avenues for research on the role of energy availability in mammalian hibernation.

APA, Harvard, Vancouver, ISO, and other styles

48

Larkin, J. E., and H. C. Heller. "Temperature sensitivity of sleep homeostasis during hibernation in the golden-mantled ground squirrel." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 270, no. 4 (1996): R777—R784. http://dx.doi.org/10.1152/ajpregu.1996.270.4.r777.

Full text

Abstract:

Brain temperature (Tbr), vigilance state, and electroencephalograph slow-wave activity (EEG SWA, 1.0-4.0 Hz) were measured during hibernation and spontaneous arousals to euthermia in seven golden-mantled ground squirrels (Spermophilus lateralis). Animals were held at air temperatures (Ta) ranging from 6 to 21 degrees C. SWA was used as a measure of the intensity of non-rapid eye movement (NREM) sleep. Squirrels that had hibernated at high Ta had lower SWA in NREM sleep in the hours following arousal than when they hibernated at low Ta. SWA in NREM sleep during euthermia immediately following arousal was significantly correlated to minimum Tbr and SWA during hibernation. The duration of the preceding hibernation bout had no significant effect on SWA during euthermia. We hypothesize that the restorative process of sleep, reflected by SWA, is temperature sensitive and is compromised by the low temperatures in hibernation. The accumulation of a SWA debt during hibernation may be related to the temperature-dependent depression of SWA during hibernation.

APA, Harvard, Vancouver, ISO, and other styles

49

Dark, J., D. R. Miller, and I. Zucker. "Gonadectomy in the spring reinstates hibernation in male golden-mantled ground squirrels." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 270, no. 6 (1996): R1240—R1243. http://dx.doi.org/10.1152/ajpregu.1996.270.6.r1240.

Full text

Abstract:

We tested the hypothesis that continued secretion of gonadal steroids is necessary to suppress hibernation in male golden-mantled ground squirrels in the weeks after the terminal arousal in spring. Juvenile and adult males were gonadectomized or sham gonadectomized 1 wk after the terminal arousal; 64% of castrated and none of the shamcastrated animals resumed hibernation. Latency to resumption of torpor was 9 +/- 2 days from the time of castration, and squirrels underwent 4.3 +/- 0.9 bouts before permanently regaining euthermia. Among squirrels that resumed hibernation, bout duration was significantly shorter and torpor was shallower after castration. Castration as late as 3 wk after the terminal arousal reinstated hibernation. We suggest that the terminal arousal of male squirrels in the spring is provoked by a steroid-independent mechanism similar to that operating earlier in the hibernation season; abandonment of hibernation is contingent on concomitant sustained increases in androgen secretion during the first few weeks of euthermia.

APA, Harvard, Vancouver, ISO, and other styles

50

Klüg-Baerwald, B. J., C. L. Lausen, S. M. Burns, and R. M. Brigham. "Physiological and behavioural adaptations by big brown bats hibernating in dry rock crevices." Journal of Comparative Physiology B 194, no. 2 (2024): 203–12. https://doi.org/10.5281/zenodo.13450626.

Full text

Abstract:

(Uploaded by Plazi for the Bat Literature Project) Winter energy stores are finite and factors influencing patterns of activity are important for overwintering energetics and survival. Hibernation patterns (e.g., torpor bout duration and arousal frequency) often depend on microclimate, with more stable hibernacula associated with greater energy savings than less stable hibernacula. We monitored hibernation patterns of individual big brown bats (Eptesicus fuscus; Palisot de Beauvois, 1796) overwintering in rock-crevices that are smaller, drier, and less thermally stable than most known cave hibernacula. While such conditions would be predicted to increase arousal frequency in many hibernators, we did not find support for this. We found that bats were insensitive to changes in hibernacula microclimate (temperature and humidity) while torpid. We also found that the probability of arousal from torpor remained under circadian influence, likely because throughout the winter during arousals, bats commonly exit their hibernacula. We calculated that individuals spend most of their energy on maintaining a torpid body temperature a few degrees above the range of ambient temperatures during steady-state torpor, rather than during arousals as is typical of other small mammalian hibernators. Flight appears to be an important winter activity that may expedite the benefits of euthermic periods and allow for short, physiologically effective arousals. Overall, we found that big brown bats in rock crevices exhibit different hibernation patterns than conspecifics hibernating in buildings and caves.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Hibernation duration'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles