I’m sure you have seen many camels with their hind legs painted with blackish jell-like solution. Why it is like that? Because the camels extracting more water from the urine, camels urine become very thick and gel-like solution. When they urinate, the sticky urine adhere with the skin and showing a blackish paint. Camel manage such mechanisms because of their unique kidney physiology. Snakes and reptiles adopt the same mechanism.http://camel4all.blogspot.com/2011/
Also, the camels do not produce sweaters in relatively normal environments but produce very little in hard work very extreme temperatures. That is why the camel has a unique water economy.