Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure

  title={Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure},
  author={Walter Arnold and Thomas Ruf and Regina Kuntz},
  journal={Journal of Experimental Biology},
  pages={4566 - 4573}
SUMMARY Many large mammals show pronounced seasonal fluctuations of metabolic rate (MR). It has been argued, based on studies in ruminants, that this variation merely results from different levels of locomotor activity (LA), and heat increment of feeding (HI). However, a recent study in red deer (Cervus elaphus) identified a previously unknown mechanism in ungulates - nocturnal hypometabolism - that contributed significantly to reduced energy expenditure, mainly during late winter. The relative… 
Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus)
The results show that Shetland ponies exhibit signs of a winter hypometabolism indicated by reduced heart rate and Ts, which seems to have maintained the capacity for seasonal adaptation to environmental conditions by seasonal fluctuations in their metabolic rate.
Thyroid hormones correlate with field metabolic rate in ponies, Equus ferus caballus
Thyroid hormones and energy expenditure are correlated in a semi-free-living ungulate during winter and across both seasons, FMR, resting heart rate and locomotor activity were positively correlated with total T3 but negatively and more weakly correlated withtotal T4.
Seasonal changes in energy expenditure, body temperature and activity patterns in llamas (Lama glama)
Llamas seem to have maintained the ability to reduce their energy expenditure and adjust their Tb under adverse environmental conditions as has been reported for some wild ungulates.
Saving energy during hard times: energetic adaptations of Shetland pony mares
It is concluded that Shetland pony mares acclimatize to different climatic conditions by changing their metabolic rate, behaviour and some physiological parameters.
Hypometabolism and basking: the strategies of Alpine ibex to endure harsh over-wintering conditions
The energetic benefits of basking can explain the strong residual seasonality of heart rate in Alpine ibex and hypometabolism and passive rewarming by basking may be of general importance as a strategy for non-hibernating mammals to survive winter in strongly seasonal habitats.
Atypical for northern ungulates, energy metabolism is lowest during summer in female wild boars (Sus scrofa)
Wild boar females had peak heart rates early in the year, which likely indicates high costs of reproduction and a prerequisite for this early reproduction as well as for high energy metabolism over winter is the broad variety of food consumed by this species, i.e., the omnivorous lifestyle.
Quantifying energetic and fitness consequences of seasonal heterothermy in an Arctic ungulate
It is shown that seasonal heterothermy can buffer the negative consequences of poor prewinter body condition or reduced winter food accessibility, leading to greater winter survival and spring energy reserves, and thus increased probability of future reproductive success.
Review: Seasonal differences in the physiology of wild northern ruminants.
  • W. Arnold
  • Medicine, Biology
    Animal : an international journal of animal bioscience
  • 2020
The transformation from the summer into the thrifty winter phenotype is also evident in the physiology of digestion, where active transport of nutrients across the intestinal epithelium is increased, resulting in more efficient exploitation of the lower amount and quality of ingested winter feed.
Seasonal Hypometabolism in Female Moose
How animals respond to a changing environment is a key question in ecological research. Animals living at higher latitudes are exposed to pronounced seasonal differences in both climate and in
Regulation of heart rate and rumen temperature in red deer: effects of season and food intake
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.


Nocturnal hypometabolism as an overwintering strategy of red deer (Cervus elaphus).
Red deer, similar to many other northern ungulates, show large seasonal fluctuations of metabolic rate, as indicated by heart rate, with a 60% reduction at the winter nadir compared with the summer peak, suggesting that reducing endogenous heat production is not restricted to hibernators and daily heterotherms but is a common and well-regulated physiological response of endothermic organisms to energetically challenging situations.
Seasonal variation in energy expenditure, water flux and food consumption of Arabian oryx Oryx leucoryx.
We report on the energy expenditure and water flux, measured in the laboratory and in the field, of the Arabian oryx Oryx leucoryx, the largest desert ruminant for which measurements of the field
Annual Rhythm of Body Weight in Przewalski Horses (Equus ferus przewalskii)
The live-weight of female Przewalski horses in a semi-natural reserve has been recorded continuously over 6 years by means of an automatic weighing machine and automatic identification and there was evidence for a phase adjustment of the annual rhythm.
Nutritional Strategies and Winter Survival of European Roe Deer in Norway
According to in vitro studies with rumen inoculum from roe deer culled at different seasons, there is apparently little cellulolytic activity during all seasons and among these winter adaptations are a 40% increase in alimentary dry matter content, reduced food intake, and increased total mean retention time of gastrointestinal fill.
Reevaluation of the Basal Metabolic Cycle in White-Tailed Deer
The data do not support the proposed existence of an inherent seasonal cycle in basal metabolism in white-tailed deer and are substantially lower than previously reported summer BMRs.
A comparison of the seasonal hormone changes and patterns of growth, voluntary food intake and reproduction in juvenile and adult red deer (Cervus elaphus) and Père David's deer (Elaphurus davidianus) hinds.
Comparing two closely related deer species which have significantly different mating and calving seasons indicates that seasonal patterns of metabolism and growth may be closely linked to those mechanisms which control the onset and termination of the breeding season.
Seasonal changes in heart rate and food intake in reindeer (Rangifer tarandus tarandus).
The results suggest that the seasonal increase in HR in summer is a consequence of increased food intake and, likewise, decreased HR in winter is a result of reduced food intake.
Seasonal metabolic rhythms of captive female white-tailed deer : a reexamination
The metabolic rate of captive female white-tailed deer is examined to determine if the seasonal rhythm now presumed for this species is a physiological adaptation or an artifact of earlier experimentental designs.
Seasonal changes in morphology and function of the gastrointestinal tract of free-living alpine marmots (Marmota marmota)
The gastrointestinal tract of alpine marmots probably continues to function throughout hibernation at a low level, with a mid-winter trough as part of an endogenous circannual rhythm, but after emergence in spring, increases in size and activity of the tract appear to be a response to ingested food rather than to an endogenous signal.