Document Detail


Energy expenditure and water flux of Rüppell's foxes in Saudi Arabia.
MedLine Citation:
PMID:  12529849     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Scattered populations of Rüppell's foxes (Vulpes rueppelli) occur across the deserts of northern Africa and Arabia. Little is known about the biology of these canids, especially the physiological mechanisms that contribute to their ability to live in such harsh environments. For individuals from Saudi Arabia, we tested the hypotheses that Rüppell's foxes have a reduced basal metabolic rate and total evaporative water loss (TEWL), parameters measured in the laboratory, and a reduced field metabolic rate (FMR) and water flux when free-living. Under basal conditions in the laboratory, males, which averaged 1,858 g in body mass, had an oxygen consumption of 914.9 mL O(2)/h, whereas females, which weighed on average 1,233 g, consumed 682.9 mL O(2)/h; rates of oxygen consumption translated to 441.4 kJ/d and 329.4 kJ/d, respectively. TEWL averaged 52.6 g H(2)O/d for males and 47.5 g H(2)O/d for females. We found no evidence that basal metabolism is reduced in Rüppell's foxes, but their TEWL was remarkably low: 50.9% of allometric prediction for males and 64.5% for females. In the wild during winter, males expended energy at a rate of 1,306.5 kJ/d, whereas females had an expenditure of 722.8 kJ/d. Analysis of covariance with FMR as the dependent variable, sex as a fixed factor, and body mass as a covariate showed no statistical difference in FMR between sexes. Water flux did not differ significantly between sexes and averaged 123 mL H(2)O/d, a value 30% lower than the kit fox from the deserts of southwestern North America. FMR was positively related to nocturnal activity levels as FMR (kJ/d) = -2,900.1+55.5 (% of time moving). The water content of prey items varied between 1.9 and 4.1 g H(2)O/g dry matter consumed. Based on these values and knowledge of their diet, we calculated that foxes captured about one rodent and a variety of anthropods per night of foraging.
Authors:
Joseph B Williams; Danny Lenain; Stephane Ostrowski; B I Tieleman; Philip J Seddon
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Physiological and biochemical zoology : PBZ     Volume:  75     ISSN:  1522-2152     ISO Abbreviation:  Physiol. Biochem. Zool.     Publication Date:    2002 Sep-Oct
Date Detail:
Created Date:  2003-01-16     Completed Date:  2003-06-11     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  100883369     Medline TA:  Physiol Biochem Zool     Country:  United States    
Other Details:
Languages:  eng     Pagination:  479-88     Citation Subset:  IM    
Affiliation:
Department of Evolution, Ecology, and Organismal Biology, 1735 Neil Avenue, Columbus, OH, 43210, USA. williams.1020@osu.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Basal Metabolism
Body Weight
Cytochrome b Group / genetics
Diet
Energy Metabolism*
Female
Foxes / classification,  genetics,  physiology*
Isoenzymes / genetics
Male
Motor Activity
Oxygen Consumption
Phylogeny
Saudi Arabia
Seasons
Water / analysis,  metabolism*
Chemical
Reg. No./Substance:
0/Cytochrome b Group; 0/Isoenzymes; 7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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