Literaturdatenbank
Literaturdatenbank |
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Peterson, C. C., & Greenshields, D. (2001). Negative test for cloacal drinking in a semi-aquatic turtle (trachemys scripta), with comments on the functions of cloacal bursae. Journal of Experimental Biology, 290(3), 247–254.
Added by: Admin (17 Aug 2008 18:17:25 UTC) |
| Resource type: Journal Article BibTeX citation key: Peterson2001 View all bibliographic details  |
Categories: General Keywords: Emydidae, Physiologie = physiology, Schildkröten = turtles + tortoises, Trachemys, Trachemys scripta Creators: Greenshields, Peterson Collection: Journal of Experimental Biology |
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| Abstract |
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Many aquatic turtles possess paired evaginations of the cloaca called cloacal bursae. Despite more than two centuries of study, little consensus exists as to the function(s) of these organs. We tested a recent suggestion that bursae could function in water uptake ("cloacal drinking"). Turtles (Trachemys scripta) were dehydrated (68-86% of maximum body mass) and given the opportunity to drink orally or cloacally. Dehydration caused increases in hematocrit and osmolality of extracellular fluid (ECF), but only after loss of 10-12% of maximum body mass, suggesting that turtles osmoregulated by reabsorbing water from the urinary bladder. Turtles drank eagerly when they could submerge their heads, and drinking was accompanied by an increase in body mass and a decrease in ECF osmolality. However, dehydrated turtles with tail and anus submerged showed no changes in mass or osmolality, suggesting that water absorption is not a significant function of the cloacal bursae in this species. Evidence for other putative functions is reviewed, leading to a pluralistic view: in cryptodires, bursae apparently function primarily in buoyancy control and secondarily in ion transport and nesting, but several pleurodires have been shown recently to use them in aquatic respiration. Copyright 2001 Wiley-Liss, Inc.
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