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Name: Mrs P.
Status: Educator
Age: 50s
Location: N/A
Country: N/A
Date: July 2004

How do reptiles concentrate their urine?

Reptiles have a different kind of kidney structure than do mammals and they are not able to concentrate their urine. They make up for this by excreting their nitrogen wastes as uric acid (which can be highly concentrated and paste-like) rather than as urea. Reptiles do absorb some water back from the urine in the cloaca, but they can not respond to dehydration by concentrating urine in the kidney as mammals do. They excrete other excess salt ions through their salt glands.

Laura Hungerford, DVM, MPH, PhD
University of Maryland

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