Author: Wendy Anne Wilson
Publisher:
ISBN:
Category :
Languages : en
Pages : 186

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Author: Jane Margaret Waterman
Publisher:
ISBN:
Category : Animal societies
Languages : en
Pages : 378

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Author: Beth A. Pettitt
Publisher:
ISBN:
Category :
Languages : en
Pages : 80

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Prior to the start of the field season, I conducted an initial experiment to determine the best alternative form of fecal storage if freezing was unavailable. I found that drying feces provides a more reliable method for long-term preservation of fecal steroid concentrations when compared to storing fecal samples in alcohol. Data associated with each of the seven parameters was analyzed using model selection to simultaneously measure the ability of different combinations of parameters to explain the observed variation in female age of sexual maturity. I found that an increase in the number of adult breeding female group mates and related adult male group mates resulted in a substantial inhibition of female reproductive maturity. I concluded that, while female Cape ground squirrels gain many advantages from group living, their sexual maturity is primarily influenced by a tug-of-war among social parameters, with minimal direct influence by environmental ones.

Author: Thomas Ruf
Publisher: Springer Science & Business Media
ISBN: 364228678X
Category : Science
Languages : en
Pages : 549

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This book summarises the newest information on seasonal adaptation in animals. Topics include animal hibernation, daily torpor, thermoregulation, heat production, metabolic depression, biochemical adaptations, neurophysiology and energy balance. The contributors to this book present interdisciplinary research at multiple levels ranging from the molecular to the ecophysiological, as well as evolutionary approaches. The chapters of this book provide original data not published elsewhere, which makes it the most up-to-date, comprehensive source of information on these fields. The book’s subchapters correspond to presentations given at the 14th International Hibernation Symposium in August 2012 in Austria. This is a very successful series of symposia (held every four years since 1959) that attracts leading researchers in the field. Like the past symposia, this meeting – and consequently the book – is aimed not only at hibernation but at covering the full range of animal adaptations to seasonal environments. For the next four years, this book will serve as the cutting-edge reference work for graduate students and scientists active in this field of physiology and ecology. .

Author: Antje Klamer Knight
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Otis Wade
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Trixie Nicole Lee
Publisher:
ISBN:
Category : Ecology
Languages : en
Pages : 120

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The Artic is home to animals that have taken adaptations to overwintering to extremes. In this dissertation, I have investigated one of these adaptations, hibernation, in two species from the Artic, the Alaska marmot (Marmota broweri) and the artic ground squirrel (Urocitellus parryii). The expression of hibernation under natural conditions in these species was compared by collecting body temperature records of free-living individuals. The Alaska marmot, a highly social species, demonstrated extreme synchrony in body temperature patterns among a family group, indicating a strong reliance on social thermoregulation. In contrast, the artic ground squirrel was confirmed to be a solitary hibernator that reduces body temperature below freezing during torpor. Both species must produce heat when soil temperatures are significantly below freezing for most of the winter. At these subfreezing ambient temperatures, the artic ground squirrel has shown an increasing reliance on nonlipid fuel during torpor, driving a loss of lean mass during hibernation of ~20%. I calibrated deuterium dilation to repeatedly estimate body composition in this species, which dramatically changes adiposity through its annual cycle, and used this technique to quantify lean mass loss throughout hibernation in a study of tissue metabolism. I also developed and applied the natural abundance of nitrogen and carbon stable isotopes as tools for monitoring differential tissue metabolism and differentiating mixed metabolic fuel use in the artic ground squirrel. These data clarified the mechanism of change in nitrogen stable isotopes and indicated that hibernating ground squirrels rebuild organ tissues while breaking down muscle tissue to meet energetic demands. Furthermore, I corroborated a shift in metabolic fuel use toward nonlipid sources during torpor at low ambient temperatures by using the carbon isotope ratio in exhaled breath in combination with respiratory quotient. This dissertation combines studies of hibernation patterns in free-living animals with experimental data on the tissues and fuels being catabolized at very low temperatures to broaden our understanding of how small mammals successfully hibernate in severe weather conditions. It also presents the development and use of stable isotope ratios as physiological tools in hibernating species.

Author: Karen Elizabeth Munroe
Publisher:
ISBN:
Category :
Languages : en
Pages : 374

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Social organization of a species may impact behavior, reproductive ecology, mating system, population genetic structure and overall fitness. A spectrum of sociality exists from solitary individuals to aggregations to integrated, highly related groups. A large body of knowledge exists for sociality and life-history characteristics of ground-dwelling sciurids, including several overarching models to explain the evolution of sociality. These models predict round-tailed ground squirrels(Xerospermophilus tereticaudus)to be solitary based on small body size (1̃25g), relatively long period of activity (January-June) and a short period of adult-juvenile overlap. However, previous behavioral observations suggest round-tailed ground squirrels have a clustered matrilineal structure with a suite of social behaviors, suggesting that they may represent a unique outlier in ground squirrel sociality models. Within the population of round-tailed ground squirrels at the Casa Grande Ruins National Monument in Coolidge, Arizona, USA, rates of amicable and agonistic interactions between adults were low, with no relationship between relatedness of individuals and rates of social interactions. No population substructure was evident with Bayesian analyses, global or pairwise FST values, and average relatedness among females did not differ from males. Contrary to previous behavioral studies, round-tailed ground squirrels did not have high levels of social behavior, nor did they form significant genetic subpopulation structuring. The active season of round-tailed ground squirrels closely followed patterns of precipitation and peak resource availability. Body mass differed between males and females, across years, and within seasons. Males were heavier than females at emergence, prior to mating and pre-hibernation, but not when females began gestation. Emergence of litters and litter size are related to amount and timing of winter rainfall. Foraging and vigilance behaviors compose 64-66% of the activity budget, but differ in that males spend a greater proportion of time foraging, whereas females spend a greater proportion of time vigilant. Round-tailed ground-squirrels have a polygynandrous mating system. Polygyny was evident in 2004, 2005, and 2006, and multiple paternity occurred in the majority of litters with 2.5 sires/litter; litter size was positively correlated with the number of sires. These findings support predictions generated by sociality models for ground-dwelling squirrels.

Author: Robert W. Fridinger
Publisher:
ISBN:
Category : Arctic ground squirrel
Languages : en
Pages : 144

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Body mass and condition and resting metabolism were assessed in a natural population of adult male and female arctic ground squirrels (AGS) living near Toolik Lake, Alaska. Assessed by the deuterium dilution method, body condition of AGS was at a low in May, but sexes differed in timing and patterns of fat and lean mass (LM) gain before immergence. Lipid mass increased sevenfold, accounting for the majority of body mass increase. Fuel use, estimated by respirometry, shifted from fat to carbohydrate over the active season. Resting metabolic rate (RMR) was at an active season low in May, reached a maximum in July and decreased before immergence in Aug-Sept. RMR declined only after peak mass was attained, suggesting that RMR reduction is not important for prehibernation fattening. RMR was modulated by the amount of LM present in males. Females reduced nocturnal body temperature and energy expenditure before initiating hibernation.

Author: Trixie Nicole Lee
Publisher:
ISBN:
Category : Marmots
Languages : en
Pages : 240

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Book Description
The Arctic is home to animals that have taken adaptations to overwintering to extremes. In this dissertation, I have investigated one of these adaptations, hibernation, in two species from the Arctic, the Alaska marmot (Marmota broweri) and the arctic ground squirrel (Urocitellus parryii). The expression of hibernation under natural conditions in these species was compared by collecting body temperature records of free-living individuals. The Alaska marmot, a highly social species, demonstrated extreme synchrony in body temperature patterns among a family group, indicating a strong reliance on social thermoregulation. In contrast, the arctic ground squirrel was confirmed to be a solitary hibernator that reduces body temperature below freezing during torpor. Both species must produce heat when soil temperatures are significantly below freezing for most of the winter. At these subfreezing ambient temperatures, the arctic ground squirrel has shown an increasing reliance on nonlipid fuel during torpor, driving a loss of lean mass during hibernation of ~20%. I calibrated deuterium dilution to repeatedly estimate body composition in this species, which dramatically changes adiposity through its annual cycle, and used this technique to quantify lean mass loss throughout hibernation in a study of tissue metabolism. I also developed and applied the natural abundance of nitrogen and carbon stable isotopes as tools for monitoring differential tissue metabolism and differentiating mixed metabolic fuel use in the arctic ground squirrel. These data clarified the mechanism of change in nitrogen stable isotopes andd, indicated that hibernating ground squirrels rebuild organ tissues while breaking down muscle tissue to meet energetic demands. Furthermore, I corroborated a shift in metabolic fuel use toward nonlipid sources during torpor at low ambient temperatures by using the carbon isotope ratio in exhaled breath in combination with respiratory quotient. This dissertation combines studies of hibernation patterns in free-living animals with experimental data on the tissues and fuels being catabolized at very low temperatures to broaden our understanding of how small mammals successfully hibernate in severe winter conditions. It also presents the development and use of stable isotope ratios as physiological tools in hibernating species.