Do camels store water in their humps?

Camels do not store water in their humps. The humps hold fat, which the body can draw on for energy when food is scarce. The idea that the hump is a water tank is a common myth, and it has been corrected by several science and zoo sources. [1] [2]

This applies to both the one-humped dromedary and the two-humped Bactrian camel. The San Diego Zoo notes that the hump leans over and droops when the camel uses up its fat, and the size of the hump changes with how much the animal has eaten. [3]

The hump is a fat store. The Library of Congress says that when a camel uses the fat, the hump goes limp and droops, and that with proper food and rest it returns to normal. EarthSky adds that a camel going without food sees its hump shrink, and if it stays hungry long enough the hump can disappear. The Cleveland Zoological Society states that one hump can store up to 80 pounds of fat. [1] [4] [5]

A reasonable follow-up is whether burning fat could supply water. Lund University biologists note that breaking down a gram of fat yields more than a gram of water, but say camels cannot use this as a water source, because they would lose too much water from their airways while taking in the oxygen needed to burn the fat. [6]

Camels are good at losing very little water. They produce thick, syrupy urine and very dry droppings. Their noses recover moisture from exhaled air: the air is cooled as it passes over the nasal surfaces, and the water vapour condenses and is reabsorbed. They also tolerate a body temperature above 40 °C during the day, which reduces the need to sweat or pant, and they shed the heat during the cooler night. [2] [6]

They also tolerate dehydration far better than most mammals. The Natural History Museum says camels can withstand losing up to 30 percent of their body weight in water, and Lund University gives a range of 30 to 40 percent. EarthSky notes that their red blood cells are small enough to keep circulating as the blood thickens, yet elastic enough to swell with water when the animal drinks. [2] [6] [4]

A thirsty camel drinks a great deal at once, but only enough to restore its normal body water, and it does not save extra for later. Sources give different figures for how much: the Library of Congress says up to 20 gallons, the Cleveland Zoological Society says up to 30 gallons in 10 minutes, and the San Diego Zoo says up to 32 gallons (145 liters). EarthSky says up to 100 liters. [1] [5] [3] [4] [6]

The Library of Congress says the water is held in the bloodstream. EarthSky reports that many scientists once believed it was kept in one of the camel's three stomachs, but says there is no evidence of long-term storage anywhere in the body. [1] [4]