Entering Hibernation

Lyman, Charles P.; Willis, John S.; Малан, А.; Wang, Lawrence C.H.

doi:10.1016/b978-0-12-460420-9.50007-6

Cited by 23 publications

(22 citation statements)

References 17 publications

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“…Some of the hallmark traits of endothermic hibernation are a depression of body temperature (T b ) and a reduction of basal metabolic rate, accompanied by falls in ventilation and heart rate (Lyman 1982;Willis 1982;Carey et al 2003;Tøien et al 2015). While the magnitude and mechanism of metabolism and T b depression in hibernating endotherms have been well studied (Lyman 1982;Nedergaard et al 1990;Storey and Storey 1990;Carey et al 2003), the same aspects of dormancy have not been extensively studied in ectothermic hibernators. It is clear that many overwintering ectotherms are capable of similar reductions in metabolism, often independent of changes in T b ; Mayhew (1965) referred to this as brumation, in order to distinguish ectothermic winter dormancy from endothermic hibernation.…”

Section: Introductionmentioning

confidence: 98%

Daily and annual cycles in thermoregulatory behaviour and cardio-respiratory physiology of black and white tegu lizards

et al. 2015

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This study was designed to determine the manner in which metabolism is suppressed during dormancy in black and white tegu lizards (Tupinambis merianae). To this end, heart rate (fH), respiration rate (fR), and deep body temperature (Tb) were continuously monitored in outdoor enclosures by radio-telemetry for nine months. There was a continuous decline in nighttime breathing and heart rate, at constant Tb, throughout the late summer and fall suggestive of an active metabolic suppression that developed progressively at night preceding the entrance into dormancy. During the day, however, the tegus still emerged to bask. In May, when the tegus made a behavioural commitment to dormancy, Tb (day and night) fell to match burrow temperature, accompanied by a further reduction in fH and fR. Tegus, under the conditions of this study, did arouse periodically during dormancy. There was a complex interplay between changes in fH and Tb associated with the direct effects of temperature and the indirect effects of thermoregulation, activity, and changes in metabolism. This interplay gave rise to a daily hysteresis in the fH/Tb relationship reflective of the physiological changes associated with warming and cooling as preferred Tb alternated between daytime and nighttime levels. The shape of the hysteresis curve varied with season along with changes in metabolic state and daytime and nighttime body temperature preferences.

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Section: Introductionmentioning

confidence: 98%

Daily and annual cycles in thermoregulatory behaviour and cardio-respiratory physiology of black and white tegu lizards

et al. 2015

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“…One effective way to deal with the challenge of a fire-denuded landscape and reduced food availability would be to use torpor. Mammalian torpor is likely used by about ¼–½ of all mammals ( Geiser and Körtner, 2010 ), is the most effective energy conservation mechanism available to mammals, is especially common in small mammals including bats and is characterised by pronounced reductions in energy and water requirements even at relatively high T a ( Macmillen, 1965 ; Lyman et al , 1982 ; Boyer and Barnes, 1999 ; Cooper et al , 2005 ; Withers and Cooper, 2008 ; Cory Toussaint et al , 2010 ; Stawski and Geiser, 2011 ; Kronfeld-Schor and Dayan, 2013 ; Johnson and Lacki, 2014 ; Withers et al , 2016 ). Torpor can reduce energy expenditure by more than 99% in comparison to normothermia (high and constant body temperature, T b ) and enables some species to survive without food for many months ( Geiser, 2007 ; Hoelzl et al , 2015 ; Ruf and Geiser, 2015 ; Nowack et al , 2017 ).…”

Section: Introductionmentioning

confidence: 99%

A burning question: what are the risks and benefits of mammalian torpor during and after fires?

Geiser

Stawski

Doty

et al. 2018

Conservation Physiology

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Although wildfires are increasing globally, available information on how mammals respond behaviourally and physiologically to fires is scant. Despite a large number of ecological studies, often examining animal diversity and abundance before and after fires, the reasons as to why some species perform better than others remain obscure. We examine how especially small mammals, which generally have high rates of energy expenditure and food requirements, deal with fires and post-fire conditions. We evaluate whether mammalian torpor, characterised by substantial reductions in body temperature, metabolic rate and water loss, plays a functional role in survival of mammals impacted by fires. Importantly, torpor permits small mammals to reduce their activity and foraging, and to survive on limited food. Torpid small mammals (marsupials and bats) can respond to smoke and arouse from torpor, which provides them with the possibility to evade direct exposure to fire, although their response is often slowed when ambient temperature is low. Post-fire conditions increase expression of torpor with a concomitant decrease in activity for free-ranging echidnas and small forest-dwelling marsupials, in response to reduced cover and reduced availability of terrestrial insects. Presence of charcoal and ash increases torpor use by captive small marsupials beyond food restriction alone, likely in anticipation of detrimental post-fire conditions. Interestingly, although volant bats use torpor on every day after fires, they respond by decreasing torpor duration, and increasing activity, perhaps because of the decrease in clutter and increase in foraging opportunities due to an increase in aerial insects. Our summary shows that torpor is an important tool for post-fire survival and, although the physiological and behavioural responses of small mammals to fire are complex, they seem to reflect energetic requirements and mode of foraging. We make recommendations on the conditions during management burns that are least likely to impact heterothermic mammals.

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“…The jumping mice (Dipodidae: Zapodinae) are another group of small mammal hibernators that are confronted with strongly seasonal environments in the northern temperate zone. However, there has been comparatively little research on hibernation in jumping mice, especially with respect to variation in phenology of the annual cycle (e.g., Lyman, Willis & Malan, 1982 ). In comparison with most ground squirrels and dormice, jumping mice have much smaller body size (<25 g) and they have not been reported to cache food ( Vander Wall, 1990 ).…”

Section: Introductionmentioning

confidence: 99%

Variation in phenology of hibernation and reproduction in the endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus)

Frey

2015

PeerJ

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Hibernation is a key life history feature that can impact many other crucial aspects of a species’ biology, such as its survival and reproduction. I examined the timing of hibernation and reproduction in the federally endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus), which occurs across a broad range of latitudes and elevations in the American Southwest. Data from museum specimens and field studies supported predictions for later emergence and shorter active intervals in montane populations relative to lower elevation valley populations. A low-elevation population located at Bosque del Apache National Wildlife Refuge (BANWR) in the Rio Grande valley was most similar to other subspecies of Z. hudsonius: the first emergence date was in mid-May and there was an active interval of 162 days. In montane populations of Z. h. luteus, the date of first emergence was delayed until mid-June and the active interval was reduced to ca 124–135 days, similar to some populations of the western jumping mouse (Z. princeps). Last date of immergence into hibernation occurred at about the same time in all populations (mid to late October). In montane populations pregnant females are known from July to late August and evidence suggests that they have a single litter per year. At BANWR two peaks in reproduction were expected based on similarity of active season to Z. h. preblei. However, only one peak was clearly evident, possibly due to later first reproduction and possible torpor during late summer. At BANWR pregnant females are known from June and July. Due to the short activity season and geographic variation in phenology of key life history events of Z. h. luteus, recommendations are made for the appropriate timing for surveys for this endangered species.

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Entering Hibernation

Cited by 23 publications

References 17 publications

Daily and annual cycles in thermoregulatory behaviour and cardio-respiratory physiology of black and white tegu lizards

Daily and annual cycles in thermoregulatory behaviour and cardio-respiratory physiology of black and white tegu lizards

A burning question: what are the risks and benefits of mammalian torpor during and after fires?

Variation in phenology of hibernation and reproduction in the endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus)

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