Water and energy balance in the Namib sand-dune lizard, Angolosaurus skoogi

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dc.contributor.advisorLouw, Gideonen_ZA
dc.contributor.advisorNicolson, Sue Wen_ZA
dc.contributor.authorClarke, Brian Craigen_ZA
dc.date.accessioned2014-10-11T12:21:24Z
dc.date.available2014-10-11T12:21:24Z
dc.date.issued1992en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThe field metabolic rate (FMR) and water flux of the herbivorous Namib sand-dune lizard, Angolosaurus skoogi, was measured during the summer non-breeding period (early January) by means of doubly labelled water. FMR was about half that expected for a lizard of this size. Water flux and laboratory measured standard metabolic rates were, however, typical of other desert lizards. It thus appeared a priori that this species was behaviourally reducing metabolic costs through reduced activity. This generated questions with regard to the ecological and physiological significance of low FMRs. Is the reduction forced by intolerable environmental conditions or the need to stay in positive water and energy balance? Alternatively, is activity reduction voluntary and geared towards optimizing growth and storage, possibly in preparation for periods of physiological stress ? The research required to answer these questions forms the basis of this thesis. There has been much discussion about the evolutionary and ecological significance of growth rates. The consensus seems to be that, under most circumstances, animals are adapted in ways that maximize growth or optimize growth in relation to realistically attainable rates of gross energy intake. Animal behaviour may be influenced by factors unrelated to growth considerations such as starvation, involuntary hypo/hyperthermia, predator evasion and social interactions. These factors may be difficult to identify and isolate, making this hypothesis difficult to test. Previous studies on the biology of A. skoogi have shown that this species has a perennially available food source, a wide range of potential body temperatures at its disposal and a low predation risk. Social interaction appear to be confined to the breeding season. This species is thus a particularly suitable subject for a scope for growth optimization study.en_ZA
dc.identifier.apacitationClarke, B. C. (1992). <i>Water and energy balance in the Namib sand-dune lizard, Angolosaurus skoogi</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/8404en_ZA
dc.identifier.chicagocitationClarke, Brian Craig. <i>"Water and energy balance in the Namib sand-dune lizard, Angolosaurus skoogi."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1992. http://hdl.handle.net/11427/8404en_ZA
dc.identifier.citationClarke, B. 1992. Water and energy balance in the Namib sand-dune lizard, Angolosaurus skoogi. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Clarke, Brian Craig AB - The field metabolic rate (FMR) and water flux of the herbivorous Namib sand-dune lizard, Angolosaurus skoogi, was measured during the summer non-breeding period (early January) by means of doubly labelled water. FMR was about half that expected for a lizard of this size. Water flux and laboratory measured standard metabolic rates were, however, typical of other desert lizards. It thus appeared a priori that this species was behaviourally reducing metabolic costs through reduced activity. This generated questions with regard to the ecological and physiological significance of low FMRs. Is the reduction forced by intolerable environmental conditions or the need to stay in positive water and energy balance? Alternatively, is activity reduction voluntary and geared towards optimizing growth and storage, possibly in preparation for periods of physiological stress ? The research required to answer these questions forms the basis of this thesis. There has been much discussion about the evolutionary and ecological significance of growth rates. The consensus seems to be that, under most circumstances, animals are adapted in ways that maximize growth or optimize growth in relation to realistically attainable rates of gross energy intake. Animal behaviour may be influenced by factors unrelated to growth considerations such as starvation, involuntary hypo/hyperthermia, predator evasion and social interactions. These factors may be difficult to identify and isolate, making this hypothesis difficult to test. Previous studies on the biology of A. skoogi have shown that this species has a perennially available food source, a wide range of potential body temperatures at its disposal and a low predation risk. Social interaction appear to be confined to the breeding season. This species is thus a particularly suitable subject for a scope for growth optimization study. DA - 1992 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1992 T1 - Water and energy balance in the Namib sand-dune lizard, Angolosaurus skoogi TI - Water and energy balance in the Namib sand-dune lizard, Angolosaurus skoogi UR - http://hdl.handle.net/11427/8404 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/8404
dc.identifier.vancouvercitationClarke BC. Water and energy balance in the Namib sand-dune lizard, Angolosaurus skoogi. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1992 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/8404en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherZoologyen_ZA
dc.titleWater and energy balance in the Namib sand-dune lizard, Angolosaurus skoogien_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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