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Chris Walzer - One of the best experts on this subject based on the ideXlab platform.
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Hibernation in the pygmy slow loris nycticebus pygmaeus multiday torpor in primates is not restricted to madagascar
Scientific Reports, 2015Co-Authors: Ulrike Streicher, Gabrielle Stalder, Tilo Nadler, Chris WalzerAbstract:Hibernation and short daily torpor are states of energy conservation with reduced metabolism and body temperature. Both Hibernation, also called multiday torpor and daily torpor are common among mammals and occur in at least 11 orders. Within the primates, there is a peculiar situation, because to date torpor has been almost exclusively reported for Malagasy lemurs. The single exception is the African lesser bushbaby, which is capable of daily torpor, but uses it only under extremely adverse conditions. For true Hibernation, the geographical restriction was absolute. No primate outside of Madagascar was previously known to hibernate. Since Hibernation is commonly viewed as an ancient, plesiomorphic trait, theoretically this could mean that Hibernation as an overwintering strategy was lost in all other primates in mainland Africa, Asia and the Americas. However, we hypothesized that a good candidate species for the use of Hibernation, outside of Madagascar should be the pygmy slow loris (Nycticebus pygmaeus), a small primate inhabiting tropical forests. Here, we show that pygmy slow lorises exposed to natural climatic conditions in northern Vietnam during winter indeed undergo torpor lasting up to 63 h, that is, Hibernation. Thus, Hibernation has been retained in at least one primate outside of Madagascar.
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How to spend the summer? Free-living dormice (Glis glis) can hibernate for 11 months in non-reproductive years
Journal of Comparative Physiology B, 2015Co-Authors: Franz Hoelzl, Claudia Bieber, Jessica S. Cornils, Hanno Gerritsmann, Gabrielle L. Stalder, Chris WalzerAbstract:Edible dormice are arboreal rodents adapted to yearly fluctuations in seed production of European beech, a major food source for this species. In years of low beech seed abundance, dormice skip reproduction and non-reproductive dormice fed ad libitum in captivity can display summer dormancy in addition to winter Hibernation. To test whether summer dormancy, that is, a very early onset of Hibernation, actually occurs in free-living dormice, we monitored core body temperature ( T _b) over ~12 months in 17 animals during a year of beech seeding failure in the Vienna Woods. We found that 8 out of 17 dormice indeed re-entered Hibernation as early as in June/July, with five of them having extreme Hibernation durations of 11 months or more (total range: 7.8–11.4 months). Thus, we show for the first time that a free-living mammal relying on natural food resources can continuously hibernate for >11 months. Early onset of Hibernation was associated with high body mass in the spring, but the distribution of Hibernation onset was bimodal with prolonged Hibernation starting either early (prior to July 28) or late (after August 30). This could not be explained by differences in body mass alone. Animals with a late Hibernation onset continued to maintain high nocturnal T _b’s throughout summer but used short, shallow torpor bouts (mean duration 7.44 ± 0.9 h), as well as occasional multiday torpor for up to 161 h.
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how to spend the summer free living dormice glis glis can hibernate for 11 months in non reproductive years
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 2015Co-Authors: Franz Hoelzl, Claudia Bieber, Jessica S. Cornils, Hanno Gerritsmann, Gabrielle L. Stalder, Chris WalzerAbstract:Edible dormice are arboreal rodents adapted to yearly fluctuations in seed production of European beech, a major food source for this species. In years of low beech seed abundance, dormice skip reproduction and non-reproductive dormice fed ad libitum in captivity can display summer dormancy in addition to winter Hibernation. To test whether summer dormancy, that is, a very early onset of Hibernation, actually occurs in free-living dormice, we monitored core body temperature (Tb) over ~12 months in 17 animals during a year of beech seeding failure in the Vienna Woods. We found that 8 out of 17 dormice indeed re-entered Hibernation as early as in June/July, with five of them having extreme Hibernation durations of 11 months or more (total range: 7.8–11.4 months). Thus, we show for the first time that a free-living mammal relying on natural food resources can continuously hibernate for >11 months. Early onset of Hibernation was associated with high body mass in the spring, but the distribution of Hibernation onset was bimodal with prolonged Hibernation starting either early (prior to July 28) or late (after August 30). This could not be explained by differences in body mass alone. Animals with a late Hibernation onset continued to maintain high nocturnal Tb’s throughout summer but used short, shallow torpor bouts (mean duration 7.44 ± 0.9 h), as well as occasional multiday torpor for up to 161 h. Electronic supplementary material The online version of this article (doi:10.1007/s00360-015-0929-1) contains supplementary material, which is available to authorized users.
Claudia Bieber - One of the best experts on this subject based on the ideXlab platform.
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How to spend the summer? Free-living dormice (Glis glis) can hibernate for 11 months in non-reproductive years
Journal of Comparative Physiology B, 2015Co-Authors: Franz Hoelzl, Claudia Bieber, Jessica S. Cornils, Hanno Gerritsmann, Gabrielle L. Stalder, Chris WalzerAbstract:Edible dormice are arboreal rodents adapted to yearly fluctuations in seed production of European beech, a major food source for this species. In years of low beech seed abundance, dormice skip reproduction and non-reproductive dormice fed ad libitum in captivity can display summer dormancy in addition to winter Hibernation. To test whether summer dormancy, that is, a very early onset of Hibernation, actually occurs in free-living dormice, we monitored core body temperature ( T _b) over ~12 months in 17 animals during a year of beech seeding failure in the Vienna Woods. We found that 8 out of 17 dormice indeed re-entered Hibernation as early as in June/July, with five of them having extreme Hibernation durations of 11 months or more (total range: 7.8–11.4 months). Thus, we show for the first time that a free-living mammal relying on natural food resources can continuously hibernate for >11 months. Early onset of Hibernation was associated with high body mass in the spring, but the distribution of Hibernation onset was bimodal with prolonged Hibernation starting either early (prior to July 28) or late (after August 30). This could not be explained by differences in body mass alone. Animals with a late Hibernation onset continued to maintain high nocturnal T _b’s throughout summer but used short, shallow torpor bouts (mean duration 7.44 ± 0.9 h), as well as occasional multiday torpor for up to 161 h.
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how to spend the summer free living dormice glis glis can hibernate for 11 months in non reproductive years
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 2015Co-Authors: Franz Hoelzl, Claudia Bieber, Jessica S. Cornils, Hanno Gerritsmann, Gabrielle L. Stalder, Chris WalzerAbstract:Edible dormice are arboreal rodents adapted to yearly fluctuations in seed production of European beech, a major food source for this species. In years of low beech seed abundance, dormice skip reproduction and non-reproductive dormice fed ad libitum in captivity can display summer dormancy in addition to winter Hibernation. To test whether summer dormancy, that is, a very early onset of Hibernation, actually occurs in free-living dormice, we monitored core body temperature (Tb) over ~12 months in 17 animals during a year of beech seeding failure in the Vienna Woods. We found that 8 out of 17 dormice indeed re-entered Hibernation as early as in June/July, with five of them having extreme Hibernation durations of 11 months or more (total range: 7.8–11.4 months). Thus, we show for the first time that a free-living mammal relying on natural food resources can continuously hibernate for >11 months. Early onset of Hibernation was associated with high body mass in the spring, but the distribution of Hibernation onset was bimodal with prolonged Hibernation starting either early (prior to July 28) or late (after August 30). This could not be explained by differences in body mass alone. Animals with a late Hibernation onset continued to maintain high nocturnal Tb’s throughout summer but used short, shallow torpor bouts (mean duration 7.44 ± 0.9 h), as well as occasional multiday torpor for up to 161 h. Electronic supplementary material The online version of this article (doi:10.1007/s00360-015-0929-1) contains supplementary material, which is available to authorized users.
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body mass dependent use of Hibernation why not prolong the active season if they can
Functional Ecology, 2014Co-Authors: Claudia Bieber, Gabrielle Stalder, Karin Lebl, Fritz GeiserAbstract:Summary 1. Hibernation is the most effective means for energy conservation during winter in mammals. The drawbacks of deep and prolonged torpor include reduced immunocompetence, and consequently, hibernators should be selected to minimize torpor expression when climatic conditions or energy availability (e.g. food or fat stores) permit. Therefore, it seems surprising that some hibernators employ extraordinary long Hibernation seasons, lasting well beyond periods with unfavourable conditions. 2. Because of their extended use of torpor, edible dormice (Glis glis) provide an ideal model for scrutinizing interactions between energy reserves (i.e. body fat stores) and thermoregulatory patterns. We used a multimodel inference approach to analyse body temperature data (i.e. use of torpor) from 42 entire Hibernation seasons over 4 years in females in relation to body mass. 3. Body mass prior to Hibernation did not affect the duration of the Hibernation season, but animals hibernated for c. 8 months, that is, 2 months longer than required by environmental conditions. Fatter individuals aroused significantly more often, had a higher mean minimum body temperature during torpor and remained euthermic for longer periods than leaner animals. 4. Surplus energy was therefore not used to shorten the Hibernation season, but to rewarm more frequently, and to allow shallower torpor bouts. These adjustments apparently serve to avoid negative effects of torpor and, perhaps equally importantly, to minimize the time active above-ground. We argue that maintaining a short active season, despite surplus energy reserves, may be explained by known beneficial effects of Hibernation on survival rates (via predator avoidance). 5. Our data provide quantitative evidence that Hibernation is a flexible tool within life-history strategies. We conclude that, apart from energetic necessities due to harsh environmental conditions, predator avoidance may be an important factor influencing patterns of Hibernation and torpor in mammals. Thus, our study indicates that climatic conditions alone are not a good predictor of Hibernation patterns or survival in hibernating species during global climate change.
B Schmidt - One of the best experts on this subject based on the ideXlab platform.
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Seasonal and daily rhythms of body temperature in the European hamster (Cricetus cricetus) under semi-natural conditions
Journal of Comparative Physiology B, 1995Co-Authors: Franziska Wollnik, B SchmidtAbstract:Body temperature of five European hamsters exposed to semi-natural environmental conditions at 47° N in Southern Germany was recorded over a 1.5-year period using intraperitoneal temperature-sensitive radio transmitters. The animals showed pronounced seasonal changes in body weight and reproductive status. Euthermic body temperature changed significantly throughout the year reaching its maximum of 37.9±0.2°C in April and its minimum of 36.1±0.4°C in December. Between November and March the hamsters showed regular bouts of Hibernation and a few bouts of shallow torpor. During Hibernation body temperature correlated with ambient temperature. Monthly means of body temperature during Hibernation were highest in November (7.9±0.8°C) and March (8.2±0.5°C) and lowest in January (4.4±0.7°C). Using periodogram analysis methods, a clear diurnal rhythm of euthermic body temperature could be detected between March and August, whereas no such rhythm could be found during fall and winter. During Hibernation bouts, no circadian rhythmicity was evident for body temperature apart from body temperature following ambient temperature with a time lag of 3–5 h. On average, Hibernation bouts lasted 104.2±23.8 h with body temperature falling to 6.0±1.7°C. When entering Hibernation the animals cooled at a rate of -0.8±0.2°C·h^-1; when arousing from Hibernation they warmed at a rate of 9.9±2.4°C·h^-1. Warming rates were significantly lower in November and December than in January and February, and correlated with ambient temperature ( r =-0.46, P
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seasonal and daily rhythms of body temperature in the european hamster cricetus cricetus under semi natural conditions
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 1995Co-Authors: Franziska Wollnik, B SchmidtAbstract:Body temperature of five European hamsters exposed to semi-natural environmental conditions at 47° N in Southern Germany was recorded over a 1.5-year period using intraperitoneal temperature-sensitive radio transmitters. The animals showed pronounced seasonal changes in body weight and reproductive status. Euthermic body temperature changed significantly throughout the year reaching its maximum of 37.9±0.2°C in April and its minimum of 36.1±0.4°C in December. Between November and March the hamsters showed regular bouts of Hibernation and a few bouts of shallow torpor. During Hibernation body temperature correlated with ambient temperature. Monthly means of body temperature during Hibernation were highest in November (7.9±0.8°C) and March (8.2±0.5°C) and lowest in January (4.4±0.7°C). Using periodogram analysis methods, a clear diurnal rhythm of euthermic body temperature could be detected between March and August, whereas no such rhythm could be found during fall and winter. During Hibernation bouts, no circadian rhythmicity was evident for body temperature apart from body temperature following ambient temperature with a time lag of 3–5 h. On average, Hibernation bouts lasted 104.2±23.8 h with body temperature falling to 6.0±1.7°C. When entering Hibernation the animals cooled at a rate of -0.8±0.2°C·h-1; when arousing from Hibernation they warmed at a rate of 9.9±2.4°C·h-1. Warming rates were significantly lower in November and December than in January and February, and correlated with ambient temperature (r=-0.46, P<0.01) and hibernating body temperature (r=-0.47, P<0.01). Entry into hibrnation occured mostly in the middle of the night (mean time of day 0148 hours ±3.4 h), while spontaneous arousals were widely scattered across day and night. For all animals regression analysis revealed free-running circadian rhythms for the timing of arousal. These results suggest that entry into Hibernation is either induced by environmental effects or by a circadian clock with a period of 24 h, whereas arousal from Hibernation is controlled by an endogenous rhythm with a period different from 24 h.
Fritz Geiser - One of the best experts on this subject based on the ideXlab platform.
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body mass dependent use of Hibernation why not prolong the active season if they can
Functional Ecology, 2014Co-Authors: Claudia Bieber, Gabrielle Stalder, Karin Lebl, Fritz GeiserAbstract:Summary 1. Hibernation is the most effective means for energy conservation during winter in mammals. The drawbacks of deep and prolonged torpor include reduced immunocompetence, and consequently, hibernators should be selected to minimize torpor expression when climatic conditions or energy availability (e.g. food or fat stores) permit. Therefore, it seems surprising that some hibernators employ extraordinary long Hibernation seasons, lasting well beyond periods with unfavourable conditions. 2. Because of their extended use of torpor, edible dormice (Glis glis) provide an ideal model for scrutinizing interactions between energy reserves (i.e. body fat stores) and thermoregulatory patterns. We used a multimodel inference approach to analyse body temperature data (i.e. use of torpor) from 42 entire Hibernation seasons over 4 years in females in relation to body mass. 3. Body mass prior to Hibernation did not affect the duration of the Hibernation season, but animals hibernated for c. 8 months, that is, 2 months longer than required by environmental conditions. Fatter individuals aroused significantly more often, had a higher mean minimum body temperature during torpor and remained euthermic for longer periods than leaner animals. 4. Surplus energy was therefore not used to shorten the Hibernation season, but to rewarm more frequently, and to allow shallower torpor bouts. These adjustments apparently serve to avoid negative effects of torpor and, perhaps equally importantly, to minimize the time active above-ground. We argue that maintaining a short active season, despite surplus energy reserves, may be explained by known beneficial effects of Hibernation on survival rates (via predator avoidance). 5. Our data provide quantitative evidence that Hibernation is a flexible tool within life-history strategies. We conclude that, apart from energetic necessities due to harsh environmental conditions, predator avoidance may be an important factor influencing patterns of Hibernation and torpor in mammals. Thus, our study indicates that climatic conditions alone are not a good predictor of Hibernation patterns or survival in hibernating species during global climate change.
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Hibernation.
Current biology : CB, 2013Co-Authors: Fritz GeiserAbstract:Hibernation (multiday torpor) and daily torpor in heterothermic mammals and birds are characterized by pronounced temporal reductions in body temperature, energy expenditure, water loss, and other physiological functions and are the most effective means for energy conservation available to endotherms. Hibernators express multiday torpor predominately throughout winter, which substantially enhances winter survival. In contrast, daily heterotherms use daily torpor lasting for several hours during the rest phase. Although torpor is still widely considered to be a specific adaptation of cold-climate species, as we will see in this primer, it is used by many diverse species from all climate zones, including the tropics. While energy conservation during adverse conditions is an important function of torpor, it is also employed to permit energy-demanding processes such as reproduction and growth, especially when food supply is limited. Even migrating birds enter torpor to conserve energy for the next stage of migration. Although many heterothermic species will be challenged by anthropogenic influences such as habitat destruction, introduced species, novel pathogens and specifically global warming, not all are likely to be affected in the same way. In fact, as argued here, it is likely that opportunistic heterotherms may be better equipped to deal with these challenges than homeotherms because heterotherms have highly flexible energy requirements, can limit foraging and reduce the risk of predation, and often are also long-lived. In contrast, strongly seasonal hibernators, especially those restricted to mountain tops, and those that have to deal with new diseases that are difficult to combat at low body temperatures, are likely to be adversely affected.
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Yearlong Hibernation in a marsupial mammal.
Naturwissenschaften, 2007Co-Authors: Fritz GeiserAbstract:Many mammals hibernate each year for about 6 months in autumn and winter and reproduce during spring and summer when they are generally not in torpor. I tested the hypothesis that the marsupial pygmy-possum (Cercartetus nanus), an opportunistic nonseasonal hibernator with a capacity for substantial fattening, would continue to hibernate well beyond winter. I also quantified how long they were able to hibernate without access to food before their body fat stores were depleted. Pygmy-possums exhibited a prolonged Hibernation season lasting on average for 310 days. The longest Hibernation season in one individual lasted for 367 days. For much of this time, despite periodic arousals after torpor bouts of ∼12.5 days, energy expenditure was reduced to only ∼2.5% of that predicted for active individuals. These observations represent the first report on body-fat-fuelled Hibernation of up to an entire year and provide new evidence that prolonged Hibernation is not restricted to placental mammals living in the cold.
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Hibernation versus daily torpor in mammals and birds physiological variables and classification of torpor patterns
Physiological and Biochemical Zoology, 1995Co-Authors: Fritz GeiserAbstract:Hibernation and daily torpor are usually considered to be two distinct patterns of heterothermia. In the present comparison we evaluated (1) whether physiological variables of torpor from 104 avian and mammalian species warrant the distinction between Hibernation and daily torpor as two different states of torpor and (2), if so, whether this distinction is best based on maximum torpor bout duration, minimum body temperature ($T_{b}$), minimum metabolic rate during torpor, or the reduction of metabolic rate expressed as percentage of basal metabolism (BMR). Initially, animals were grouped into species displaying either daily torpor or prolonged torpor (Hibernation) according to observations from original sources. Both cluster and discriminant analyses supported this division, and further analyses were therefore based on these two groups. Frequency distributions for all tvariables tested differed significantly (P < 0.001) between daily torpor and Hibernation. The average maximum torpor bout duration was 355...
Franz Hoelzl - One of the best experts on this subject based on the ideXlab platform.
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How to spend the summer? Free-living dormice (Glis glis) can hibernate for 11 months in non-reproductive years
Journal of Comparative Physiology B, 2015Co-Authors: Franz Hoelzl, Claudia Bieber, Jessica S. Cornils, Hanno Gerritsmann, Gabrielle L. Stalder, Chris WalzerAbstract:Edible dormice are arboreal rodents adapted to yearly fluctuations in seed production of European beech, a major food source for this species. In years of low beech seed abundance, dormice skip reproduction and non-reproductive dormice fed ad libitum in captivity can display summer dormancy in addition to winter Hibernation. To test whether summer dormancy, that is, a very early onset of Hibernation, actually occurs in free-living dormice, we monitored core body temperature ( T _b) over ~12 months in 17 animals during a year of beech seeding failure in the Vienna Woods. We found that 8 out of 17 dormice indeed re-entered Hibernation as early as in June/July, with five of them having extreme Hibernation durations of 11 months or more (total range: 7.8–11.4 months). Thus, we show for the first time that a free-living mammal relying on natural food resources can continuously hibernate for >11 months. Early onset of Hibernation was associated with high body mass in the spring, but the distribution of Hibernation onset was bimodal with prolonged Hibernation starting either early (prior to July 28) or late (after August 30). This could not be explained by differences in body mass alone. Animals with a late Hibernation onset continued to maintain high nocturnal T _b’s throughout summer but used short, shallow torpor bouts (mean duration 7.44 ± 0.9 h), as well as occasional multiday torpor for up to 161 h.
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how to spend the summer free living dormice glis glis can hibernate for 11 months in non reproductive years
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 2015Co-Authors: Franz Hoelzl, Claudia Bieber, Jessica S. Cornils, Hanno Gerritsmann, Gabrielle L. Stalder, Chris WalzerAbstract:Edible dormice are arboreal rodents adapted to yearly fluctuations in seed production of European beech, a major food source for this species. In years of low beech seed abundance, dormice skip reproduction and non-reproductive dormice fed ad libitum in captivity can display summer dormancy in addition to winter Hibernation. To test whether summer dormancy, that is, a very early onset of Hibernation, actually occurs in free-living dormice, we monitored core body temperature (Tb) over ~12 months in 17 animals during a year of beech seeding failure in the Vienna Woods. We found that 8 out of 17 dormice indeed re-entered Hibernation as early as in June/July, with five of them having extreme Hibernation durations of 11 months or more (total range: 7.8–11.4 months). Thus, we show for the first time that a free-living mammal relying on natural food resources can continuously hibernate for >11 months. Early onset of Hibernation was associated with high body mass in the spring, but the distribution of Hibernation onset was bimodal with prolonged Hibernation starting either early (prior to July 28) or late (after August 30). This could not be explained by differences in body mass alone. Animals with a late Hibernation onset continued to maintain high nocturnal Tb’s throughout summer but used short, shallow torpor bouts (mean duration 7.44 ± 0.9 h), as well as occasional multiday torpor for up to 161 h. Electronic supplementary material The online version of this article (doi:10.1007/s00360-015-0929-1) contains supplementary material, which is available to authorized users.