The nasal surfaces of camels help conserve water by using hygroscopic properties to remove water from air during exhalation.

     
  "We have found that camels can reduce the water loss due to evaporation from the respiratory tract in two ways: (1) by decreasing the temperature of the exhaled air and (2) by removal of water vapour from this air, resulting in the exhalation of air at less than 100% relative humidity (r.h.). Camels were kept under desert conditions and deprived of drinking water. In the daytime the exhaled air was at or near body core temperature, while in the cooler night exhaled air was at or near ambient air temperature. In the daytime the exhaled air was fully saturated, but at night its humidity might fall to approximately 75% r.h. The combination of cooling and desaturation can provide a saving of water of 60% relative to exhalation of saturated air at body temperature. The mechanism responsible for cooling of the exhaled air is a simple heat exchange between the respiratory air and the surfaces of the nasal passageways. On inhalation these surfaces are cooled by the air passing over them, and on exhalation heat from the exhaled air is given off to these cooler surfaces. The mechanism responsible for desaturation of the air appears to depend on the hygroscopic properties of the nasal surfaces when the camel is dehydrated. The surfaces give off water vapour during inhalation and take up water from the respiratory air during exhalation. We have used a simple mechanical model to demonstrate the effectiveness of this mechanism." (Schmidt-Nielsen and others 1981:305)
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Thermoregulation in African camels appears to be related to water availability.

   
  "When African camels (Camelus dromedarius) do not get enough water, their body temperature's amplitude (the difference between its highest and lowest values) increases from 3.6°F (2°C) to as much as 10.8°F (6°C)." (Shuker 2001:91)
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The red blood cells of dromedary camels circulate even in thick, dehydrated blood due to their oval shape.

   
  "The dromedary camel is one of the most well adapted to hot arid climates. Contrary to popular opinion, the camel does not store water any more than any other species, yet it need not drink water for days. The camel is able to tolerate extreme dehydration and has been known to safely lose body water equal to 40% of its body weight. Such a water loss would be lethal in any other animal. In the camel, plasma volume is maintained at the expense of tissue fluid, thus circulation is not impaired. The small oval erythrocyte of the camel continues to circulate despite increased blood viscosity.

"Even after severe dehydration, the camel is able to drink sufficient water at one session to make up the deficit. This amount of water would cause severe osmotic problems in humans or other animals. In the camel, water is absorbed from the stomach and intestines slowly, allowing equilibrium to be established. The erythrocytes are able to avoid osmotic problems by swelling to 240% of their initial volume without rupturing. In other species, erythrocytes can swell only to 150%.¹⁶ Lamoids share some of these characteristics with camels.[Paragraph on evaporative cooling.] The kidney of the camel is capable of concentrating urine markedly to diminish water loss. The urine becomes as thick as syrup, and salt content may be increased to twice the concentration of salt in sea water. Water is extracted in the form of fecal pellets to such a degree that they can be used for fuel immediately upon voiding." (Fowler 1998:235)
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