ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Cham :Springer International Publishing :
    Keywords: Physiology. ; Veterinary medicine. ; Ecology . ; Animal Physiology. ; Veterinary Science. ; Ecology.
    Description / Table of Contents: Chapter 1. Introduction, Background and Definitions -- Chapter 2. Quantifying Torpor -- Chapter 3. Diversity and Geography of Torpor and Heterothermy -- Chapter 4. Patterns and Expression of Torpor -- Chapter 5. Physiology and Thermal Biology -- Chapter 6. Seasonality of Daily Torpor and Hibernation -- Chapter 7. Ecological and Behavioural Aspects of Torpor -- Chapter 8. Torpor during Reproduction and Development -- Chapter 9. Dietary Lipids, Thermoregulation and Torpor Expression -- Chapter 10. Evolution of Endothermy and Torpor -- Chapter 11. Concluding Remarks.
    Abstract: This book provides an in-depth overview on the functional ecology of daily torpor and hibernation in endothermic mammals and birds. The reader is well introduced to the physiology and thermal energetics of endothermy and underlying different types of torpor. Furthermore, evolution of endothermy as well as reproduction and survival strategies of heterothermic animals in a changing environment are discussed. Endothermic mammals and birds can use internal heat production fueled by ingested food to maintain a high body temperature. As food in the wild is not always available, many birds and mammals periodically abandon energetically costly homeothermic thermoregulation and enter an energy-conserving state of torpor, which is the topic of this book. Daily torpor and hibernation (multiday torpor) in these heterothermic endotherms are the most effective means for energy conservation available to endotherms and are characterized by pronounced temporal and controlled reductions in body temperature, energy expenditure, water loss, and other physiological functions. Hibernators express multiday torpor predominately throughout winter, which substantially enhances winter survival. In contrast, daily heterotherms use daily torpor lasting for several hours usually during the rest phase, some throughout the year. Although torpor is still widely considered to be a specific adaptation of a few cold-climate species, it is used by many animals from all climate zones, including the tropics, and is highly diverse with about 25-50% of all mammals, but fewer birds, estimated to use it. While energy conservation during adverse conditions is an important function of torpor, it is also employed to permit or facilitate 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, whereas bats may use it to deal with heat. Even though 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 it appears that opportunistic heterotherms because of their highly flexible energy requirements, ability to limit foraging and reduce the risk of predation, and often pronounced longevity, may be better equipped to deal with anthropogenic challenges than homeotherms. 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. This book addresses researchers and advanced students in Zoology, Ecology and Veterinary Sciences.
    Type of Medium: Online Resource
    Pages: XVII, 317 p. 116 illus., 55 illus. in color. , online resource.
    Edition: 1st ed. 2021.
    ISBN: 9783030755256
    Series Statement: Fascinating Life Sciences,
    DDC: 571.1
    Language: English
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 66 (2004), S. 239-274 
    ISSN: 0066-4278
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Biology
    Notes: Although it is well established that during periods of torpor heterothermic mammals and birds can reduce metabolic rates (MR) substantially, the mechanisms causing the reduction of MR remain a controversial subject. The comparative analysis provided here suggests that MR reduction depends on patterns of torpor used, the state of torpor, and body mass. Daily heterotherms, which are species that enter daily torpor exclusively, appear to rely mostly on the fall of body temperature (Tb) for MR reduction, perhaps with the exception of very small species and at high torpor Tb, where some metabolic inhibition may be used. In contrast, hibernators (species capable of prolonged torpor bouts) rely extensively on metabolic inhibition, in addition to Tb effects, to reduce MR to a fraction of that observed in daily heterotherms. In small hibernators, metabolic inhibition and the large fall of Tb are employed to maximize energy conservation, whereas in large hibernators, metabolic inhibition appears to be employed to facilitate MR and Tb reduction at torpor onset. Over the ambient temperature (Ta) range where torpid heterotherms are thermo-conforming, the Tb-Ta differential is more or less constant despite a decline of MR with Ta; however, in thermo-regulating torpid individuals, the Tb-Ta differential is maintained by a proportional increase of MR as during normothermia, albeit at a lower Tb. Thermal conductance in most torpid thermo-regulating individuals is similar to that in normothermic individuals despite the substantially lower MR in the former. However, conductance is low when deeply torpid animals are thermo-conforming probably because of peripheral vasoconstriction.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillan Magazines Ltd.
    Nature 407 (2000), S. 318-318 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Torpor is a natural state in which animals show a substantial and controlled reduction of body temperature to conserve energy. A few small birds (weighing less than 80 g) are known to use it as a survival strategy in winter, but we have discovered that a large bird, the Australian tawny ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 113 (1998), S. 170-178 
    ISSN: 1432-1939
    Keywords: Key words Alpine ; Natural hibernation ; Marsupial ; Pygmy-possum ; Torpor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The hibernating marsupial mountain pygmy-possum (Burramys parvus, 40 g) has to raise its slow-growing offspring during a short alpine summer. Only females provide parental care, while after mating males emigrate to marginal habitats often at lower altitudes which can sustain only low possum densities. We predicted that the hibernation strategies in mountain pygmy-possums are distinct from those of similar-sized placental hibernators, because of the developmental constraints in marsupials and because hibernation differs between the sexes. Using temperature-sensitive radio transmitters, we studied the hibernation patterns of free-living male and female mountain pygmy-possums living in a north- and a south-facing boulder field (Kosciusko National Park) for two consecutive winters. Individual possums commenced hibernation several months before the snow season. As in other hibernators, torpor in the mountain pygmy-possum was interrupted by periodic arousals which occurred most often during the late afternoon. Torpor bouts initially lasted a few days when the hibernacula temperature (T hib) ranged from 4 to 7°C. As the hibernation season progressed, torpor bouts became longer and possum body temperatures (T b) approached 2°C. The T bs of females were significantly lower and torpor bouts were longer in the second half of the hibernation season than in males. Between torpor bouts, both sexes were often active and left hibernacula for periods of up to 5 days. Especially during the first months of the hibernation season, possums also frequently changed hibernacula sites probably in an attempt to select a site with a more suitable microclimate. Emergence from hibernation was closely coupled with the disappearance of snow from the possum habitat (September 1995, October 1996) and the limited fat stores probably dictate an opportunistic spring emergence. However, in 1995, spring was early and males emerged significantly earlier than females. In 1996, when snow melt was delayed, this difference vanished. Testes are regressed in males during hibernation and the time needed for testes growth and spermatogenesis favours an earlier emergence for males which was probably achieved by their preference for the more sun exposed north-facing boulder field. A sexual dimorphism in hibernation strategies and spring emergence therefore enables mountain pygmy-possums to cope with their harsh alpine environment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-1939
    Keywords: Key words Energetics ; Torpor ; Subtropical ; Nectar availability ; Thermoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Little is known about how animals from tropical and subtropical climates adjust their energy expenditure to cope with seasonal changes of climate and food availability. To provide such information, we studied the thermal physiology, torpor patterns and energetics of the nocturnal blossom-bat (Syconycteris australis 18 g) from a subtropical habitat in both summer and winter. In both seasons, S. australis frequently entered daily torpor at ambient temperatures between 12 and 25°C when food and water were withheld. Unlike patterns observed in temperate animals, mean minimum metabolic rates during torpor were lower in summer (0.47 ± 0.07 ml O2 g−1 h−1) than in winter (0.75 ± 0.11 ml O2 g−1 h−1). Body temperatures during torpor were regulated at 19.3 ± 1.0°C in summer and at 23.4 ± 2.0°C in winter. Torpor bout duration was significantly longer in summer (7.3 ± 0.6 h) than in winter (5.5 ± 0.3 h), but in both seasons, bout duration was not affected by ambient temperature. Consequently, average daily metabolic rates were also significantly lower in summer than in winter. Body temperatures and metabolic rates in normothermic bats did not change with season. Our findings on seasonal changes of torpor in this bat from the subtropics are opposite to those made for many species from cold climates which generally show deeper and longer torpor in winter and are often entirely homeothermic in summer. More pronounced torpor in subtropical S. australis in summer may be due to low or unpredictable nectar availability, short nights which limit the time available for foraging, and long days without access to food. Thus, the reversed seasonal response of this subtropical bat in comparison to temperate species may be an appropriate response to ecological constraints.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1432-1939
    Keywords: Antechinus ; Body mass ; Season ; Torpor ; Thermoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Season and body mass influence torpor in mammals. However, the effects of the two factors are often difficult to distinguish because body mass in many species changes with season. The present study attempted to separate seasonal and body mass related alterations of torpor. Adult female Antechinus stuartii and A. flavipes (Marsupialia), which were about half the size of males of the respective species, showed longer and deeper torpor than males. When the two species were compared, torpor in A. stuartii, the smaller species, was more pronounced than in A. flavipes. Juveniles of both species had lower body temperatures and longer torpor durations than adults. Torpor was most pronounced in juvenile males during summer; in winter, when males had grown to adult size, the use of torpor was reduced. Seasonal changes in torpor of adults were not distinct. These results suggest that the influence of body mass on torpor in these Antechinus species is stronger than that of season.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 156 (1986), S. 751-757 
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Body temperatures (T b), rates of oxygen consumption ( $$\dot V_{O_2 }$$ ) and the loss in body mass of the small insectivorous dasyurid marsupialAntechinomys laniger were determined at different ambient temperatures (T a). 2. Most animals entered torpor belowT a 27°C when food was witheld. Spontaneous torpor was observed frequently atT a 19 and 12.5°C. 3. An increase in $$\dot V_{O_2 }$$ and ΔT (T b-T a) was observed during torpor below aT a of about 11°C. The lowest individualT b measured was 11.0°C. 4. The linear increase in $$\dot V_{O_2 }$$ during torpor belowT a 11°C was parallel to theT a related increased in metabolism of normothermic resting, active, and arousing animals. 5. Torpor lasted between 2 and 16 h and the longest durations were observed atT a 13–20°C; below and above this temperature range torpor bouts were shorter. 6. The lowest relative weight loss was observed at theT a of the longest torpor bouts and lowest metabolism during torpor. 7. Both the time of the activity peaks and onset of torpor were dependent onT a and were observed later in the night at higherT a. Torpor commenced before the onset of light. 8. Arousal rates were rapid and the arousal times increased exponentially with decreasing Ta.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 155 (1985), S. 711-715 
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The relationship, between the body temperature (T b), the Arrhenius critical temperature (T *), and the apparent activation energy aboveT *) (E a1), of liver and heart mitochondrial respiratory enzymes from eleven homeothermic and eight heterothermic species was determined using a linear regression analysis. 2. An inverse relation was observed between,T * andE a1 during torpor and hibernation. 3. In all thermoregulatory states,T * decreased withT b andT * was equal to or belowT b. 4. During torporE a1 increased in a linear manner asT b was lowered. 5. It appears that the above Arrhenius parameters are closely linked to the thermoregulatory state of endotherms and thus may represent an, adaptation for function at lowT b's.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 167 (1997), S. 416-422 
    ISSN: 1432-136X
    Keywords: Key words Dietary cholesterol ; Hibernation ; Metabolic rate ; Rodent ; Tamias amoenus ; Testosterone ; Torpor bouts ; Thermoregulation ; Yellow-pine chipmunk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Dietary cholesterol can affect both body lipid composition and steroid hormone concentration. We investigated whether a diet rich in cholesterol influences torpor patterns of hibernating chipmunks (Tamias amoenus) and, if so, whether these changes are better explained by diet-induced changes in body lipid composition or the concentration of testosterone, which at high levels inhibits torpor. Two groups of chipmunks were maintained either on a cholesterol diet (rodent chow containing 10% cholesterol) or a control diet (rodent chow) during pre-hibernation fattening and throughout the hibernation season. Torpid chipmunks on the cholesterol diet had significantly lower minimum body temperatures (−0.2 ± 0.2 vs +0.6 ± 0.2 °C), lower metabolic rates (0.029 ± 0.002 ml O2 g−1h−1 vs 0.035 ± 0.001 ml O2 g−1h−1), and longer torpor bouts at −1 °C (6.8 ± 0.5 vs 4.1 ± 1.0 days) than chipmunks on the control diet. Dietary cholesterol resulted in a significant increase in blood plasma cholesterol (sevenfold), liver cholesterol content (6.9-fold) and liver triglyceride content (3.5-fold) in comparison to controls. In contrast, dietary cholesterol had no detectable effect on the concentration of plasma testosterone, which was very low in both groups. Since torpor was deeper and longer in animals on the cholesterol diet our study suggests that torpor patterns of chipmunks were either directly affected by the dietary cholesterol or via changes in body lipid composition.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 155 (1984), S. 125-133 
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The thermal response of liver and heart mitochondrial succinate oxidase and succinate cytochromec reductase of eleven homeothermic and six heterothermic species was compared. 2. Arrhenius plots of succinate oxidase and succinate cytochromec reductase of homeotherms exhibited a meanT * (Arrhenius critical temperature) of 22.6 °C. In normothermic heterothermsT * occurred at a mean temperature of 20.1 °C. During the season in which they entered torpor, two of the heterothermic mammals exhibited a meanT * at 10.9 °C, whilst for three species noT * was observed in the temperature range 5 °C to 40 °C. 3. The loweredT * in the heterothermic species was accompanied by an increase in theE a and Q10 both above and below the discontinuity in the Arrhenius plot. The increase Q10 of the mitochondrial enzymes isolated from animals during torpor was identical to the Q10 for O2 consumption for animals entering torpor. This may represent an important factor for energy conservation during torpor.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...