Seasonal variations in basal metabolic rate, lower critical temperature and responses to temporary starvation in the arctic fox (Alopex lagopus) from Svalbard

@article{Fuglesteg2005SeasonalVI,
  title={Seasonal variations in basal metabolic rate, lower critical temperature and responses to temporary starvation in the arctic fox (Alopex lagopus) from Svalbard},
  author={Britt Nanny Fuglesteg and {\O}. E. Haga and Lars P. Folkow and Eva Fuglei and Arnoldus Schytte Blix},
  journal={Polar Biology},
  year={2005},
  volume={29},
  pages={308-319}
}
Metabolic rates of four resting, post-absorptive male adult summer- and winter-adapted captive arctic foxes (Alopex lagopus) were recorded. [] Key Result Basal metabolic rates (BMR) varied seasonally with a 36% increase from winter to summer, while body mass was reduced by 17% in the same period. The lower critical temperature (T1c) of the winter-adapted arctic fox was estimated to −7°C, whereas Tlc during summer was 5°C.
Seasonal Metabolic Acclimatization in a Northern Population of Free-Ranging Snowshoe Hares, Lepus americanus
TLDR
It is suggested that resource constraints associated with a herbivorous diet in regions and seasons of poor forage quality favors an energetically conservative approach to winter acclimatization.
Seasonal Variation of Resting Metabolic Rate and Body Mass in Free-Living Weasels Mustela nivalis
TLDR
This study demonstrated that individual weasels were consistent in how their BM and RMR deviated from the seasonal means for the population (intraclass correlation, and 0.33, respectively) and the relatively constant BM at the population level across seasons is due to a relative constancy of BM in individuals.
The cold shoulder: free-ranging snowshoe hares maintain a low cost of living in cold climates
TLDR
A positive, low Ta portion of this relationship is referred to as the cold shoulder, and it is suggested that it may reflect the general necessity for free-ranging mammals to use behavioural and physiological means to conserve energy during long winters when cold conditions coincide with resource scarcity.
Reduced Metabolic Cost of Locomotion in Svalbard Rock Ptarmigan (Lagopus muta hyperborea) during Winter
TLDR
It is demonstrated that winter birds have a reduced cost of locomotion when compared to summer birds, a remarkable finding given that during winter these birds have almost twice the body mass of those in summer.
Surviving on cached foods — the energetics of egg-caching by arctic foxes
TLDR
The energy content of greater snow goose eggs was measured and it was estimated that eggs lost only ~8% of their dry mass over 60 days of storage in the ground, and an adult arctic fox would need to recover 160-220 stored eggs to survive 6 months in resting conditions during cold winter temperatures.
Regulation of heart rate and rumen temperature in red deer: effects of season and food intake
TLDR
The hypothesis that a reduction in body temperature is a physiological mechanism employed even by large mammals, like red deer, to reduce their energy expenditure during periods of negative energy balance is supported.
Adaptations to polar life in mammals and birds
  • A. S. Blix
  • Environmental Science
    Journal of Experimental Biology
  • 2016
TLDR
Polar animals are well adapted to the hardships of polar life, particularly when the sun never sets in summer and darkness prevails during winter, high-latitude animals become intermittently active around the clock, allowing opportunistic feeding at all times.
Allometry of thermal variables in mammals: consequences of body size and phylogeny
  • A. Riek, F. Geiser
  • Environmental Science
    Biological reviews of the Cambridge Philosophical Society
  • 2013
TLDR
The first phylogenetic analyses on scaling of lower and upper critical temperatures and the breadth of the TNZ in 204 mammal species from diverse orders are provided, suggesting that BMR per se affects the influence of body mass on TNZ only marginally.
Advantage to lower body temperatures for a small mammal (Rattus fuscipes) experiencing chronic cold
TLDR
The lower Tbs recorded in some small mammals in winter are not necessarily due to lower levels of activity but can result from a regulated reduction in Tb in response to cooler ambient temperatures.
Coat color mismatch improves survival of a keystone boreal herbivore: energetic advantages exceed lost camouflage
TLDR
It is suggested that the increased coat insulation and lower metabolic rates of winter acclimatized hares confer energetic advantages to white mismatched hares that reduce their mortality risk and increase survival.
...
...

References

SHOWING 1-10 OF 42 REFERENCES
Seasonal trends in body mass, food intake and resting metabolic rate, and induction of metabolic depression in arctic foxes (Alopex lagopus) at Svalbard
TLDR
A significant reduction in RMR with starvation was recorded both in May and November, indicating an adaptation to starvation in arctic foxes, and indicates that metabolic responses to starvation may be masked by thermoregulatory needs.
Metabolic and respiratory responses of arctic mammals to ambient temprature during the summer
Photoperiod and fur lengths in the arctic fox (Alopex lagopus L.)
TLDR
The growth of fur in the Arctic fox parallels annual changes in ambient temperature and photoperiod and appears to be a remarkable parallel between the body-to-ambient temperature gradient and the fur lengths.
Adaptation to cold in arctic and tropical mammals and birds in relation to body temperature, insulation, and basal metabolic rate.
TLDR
There is no evidence of adaptive low body temperature in arctic mammals and birds, or highBody temperature in tropical mammals andbirds.
Energy cost of running in an Arctic Fox, Alopex Lagopus
TLDR
There was a significant positive linear relationship between heart rate and weight specific metabolic rate, suggesting that heart rate can be used as an indicator of metabolic rate.
Seasonal changes in the effects of starvation on metabolic rate and regulation of body weight in Svalbard Ptarmigan
TLDR
The potential durability of the body fat reserves of starving Svalbard Ptarmigan was assessed at monthly intervals during the dark part of the winter to indicate that body weight in the Svalberg Ptarmigans is regulated according to a seasonally changing set-point.
Response to cold in the blue fox and raccoon dog as evaluated by metabolism, heart rate and muscular shivering: a re-evaluation.
Heat regulation in some arctic and tropical mammals and birds.
A series of arctic and tropical mammals and birds at Point Barrow, Alaska (lat. 71° N.) and in Panama (lat. 9° N.) was subjected to various air temperatures in a respiration chamber where the heat
Behavioral changes in fasting emperor penguins: evidence for a "refeeding signal" linked to a metabolic shift.
TLDR
It is suggested that at a threshold of body mass, a metabolic and endocrine shift, possibly related to a limited availability of fat stores, acts as a "refeeding signal" that improves the survival of penguins to fasting.
Fat deposition and seasonal variation in body composition of arctic foxes in Svalbard
TLDR
The seasonal variation in body composition of arctic foxes (Alopex lagopus) was studied to determine the adaptive significance of fat deposition in this species, and the amount of fat deposited did not decline between November and March of any year.
...
...