Adaptations
Dromedary camels have several adaptations for their desert habitat. A double row of eyelashes and the unique ability of closing their nostrils enables the camels to prevent the sand]] and dust from entering, even in a sandstorm. Dromedaries can conserve water by fluctuating their body temperature throughout the day from 34–41.7 °C (93–107 °F), which saves water by avoiding perspiration at the rise of the external temperature. The kidneys are specialized so that not much water is excreted. Groups of camels also avoid excess heat from the environment by pressing against each other.
Dromedary camels can tolerate greater than 30% water loss, which is almost impossible for most of other mammals. In the Sahara, they can survive for as long as October to April or May without water. In temperatures of 30–40 °C (86–104 °F) they need water every 10 to 15 days, and only in the hottest temperatures do they take water every 4 to 7 days. They drink at the speed of 10–20 L (2.6–5.3 US gal) per minute. Water is expended primarily from interstitial and intracellular bodily fluids. The oval red blood cells, unique to the dromedaries, help them survive for over six months without water. They have the unique capability of drinking 100 L (26 US gal) of water in just 10 minutes. A very thirsty animal can drink up even 30 US gal (110 L) of water in only 13 minutes and 200 L (53 US gal) in three minutes.
The hump stores up to 80 lb (36 kg) of fat, which a camel can break down into water and energy when sustenance is not available. If the hump is small, the animal can show signs of starvation. In a 2005 study it was found that the mean volume of adipose tissues (in the external part of the hump), that have cells to store lipids (adipocytes), is related to the dromedary's unique mechanism of food and water storage. In case of starvation, they can even eat fish and bones, and drink brackish and salty water. The hair is longer at the throat, hump and shoulders. The pads widen under the weight of the dromedary when it steps on the ground. This prevents the dromedary from sinking much into the sand. When the dromedary walks, it moves both the feet on the same side of the body simultaneously, then the same movement is repeated on the other side of the body. This way of walking makes the dromedary's body swing from side to side as it walks, hence the nickname of the animal: "the ship of the desert". The thick lips help in eating coarse and thorny plants.
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