Today I found out Camels’ humps are not filled with water.

So what are Camel humps filled with?  It turns out, fat.  These fat humps can weigh as much as 80 pounds and allow the Camel to comfortably go one to two weeks without eating, if necessary.

Now, some of you out there might be saying to yourselves, “Well, but 1 gram of fat actually gets converted to more than 1 gram of water during the metabolic process, so it actually is a kind of water store.”  This is correct in principle, but ends up not helping the Camel out any in terms of water supply.  Even though more water is produced processing the fat than there was fat, gram for gram, the metabolic process actually uses quite a bit of water due to the arid conditions Camels live in.  Basically, they lose a lot of water through their lungs getting the oxygen necessary to process the fat. So the net effect of processing the fat actually results in less water than there was before.

So where do the Camels store extra water?  It turns out, mostly in their blood and other places there are already fluids in their body.  There really is no central water store anywhere in a Camel.  What allows a Camel to survive in desert environments is mainly just that they are incredibly efficient with their water usage.  In fact, they are so efficient, that in milder climates a Camel can get all the water they need just from eating relatively green plant life.

Their bodies conserve water in just about every way imaginable.  For instance, when they pee, their urine contains very little water, being more of a pasty substance that has approximately the consistency of syrup.  On the other end of things, their feces comes out almost completely dried out and can be used right away by humans for making fires or the like.  For comparison, human fecal matter typically is made up of about 75% water.

A major area most animals lose water, particularly in arid environments, is by breathing.  Camels are no exception, but their breathing system is much more efficient than most.  Their nostrils have a mechanism for trapping moisture in their breath before it is exhaled.  This moisture is then returned to their bodily fluids.

The other major area most mammals lose water in hot areas is through sweat.  It turns out, Camels don’t need to sweat very much to stay cool. There are a few things that go into this, most impressive of which is that their body temperatures can comfortably range from about 93 degrees Fahrenheit to 106 degrees Fahrenheit without any real negative side effects.

Their bodies are also well equipped for keeping heat out (for more on this see the Bonus Factoids section below).  After a cool desert night, their body temperature will be around 93 degree Fahrenheit.  Given their large size and their body’s ability to keep heat out, it ends up taking a while for their temperature to rise to closer to the 106 degree Fahrenheit level.  So in some cases, the Camel may not need to sweat at all during a given day, depending on the ambient temperature and how hard they are working.

However, if they do get close to that 106 degree Fahrenheit threshold, their sweat mechanism will kick in.  Like the rest of their body when it comes to water usage, their sweat mechanism is as efficient as sweating can be, with the sweat evaporating at the skin surface level rather than soaking into their hair and wasting some of the cooling effect in evaporating off that hair.

Another interesting thing is how a Camel’s body actually manages water internally.  When they need water, their body will first get the water from all fluid parts of their body except the bloodstream.  This allows their blood to continue to flow normally, even when they are relatively dehydrated.  They can withstand up to a 25% weight decrease from water loss and it isn’t until they start getting close to that level that their main store of water in their blood starts to get used.  For comparison on how impressive that 25% number is, most mammals will experience cardiac failure around 12-15% weight decrease due to water loss.

This all adds up to a Camel that isn’t carrying any extra weight being able to go around two to three weeks in a desert environment without needing to drink water.  On the other hand, if the Camel is being used as a pack Camel and is carrying a lot of weight, they can go three or four days in that environment without needing to take in any water.

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Bonus Facts:

• A Camel’s blood cells also have some unique properties among mammals.  The blood cells are in the shape of elongated ovals, instead of round, which allows them to flow more freely when the Camel is dehydrated.  The  blood cells are also able to handle large swings in water levels without rupturing, which is essential for the blood stream’s ability to store extra water.
• The Camel’s thick coat does a good job of reflecting sunlight and providing nice insulation from the sun and the radiant heat coming from the desert sand.  For comparison, a shorn Camel will sweat nearly 50% more than a non-shorn Camel in order to maintain the same body temperature.
• Their long legs also work well to help keep their body temperature down.  By keeping the main part of their body mass higher up, it protects them somewhat from the hot sand which radiates the sun’s heat quite well.
• It turns out, having a hump of fat, instead of fat evenly distributed throughout their bodies, ends up allowing for better heat dissipation through the rest of their body and so also helps keep their body temperature down.  The hunk of fat being on their back also helps insulate the top of their body from the sun.  The fat doesn’t need much of any oxygen so the blood flow to this region is extremely low.  This, combined with the fact that fat conducts heat slower than water does, makes for a nice little insulation spot on their backs between their body and the sun.
• Camels can drink up to 25-40 gallons within a 10-15 minute span.  Their gut then slowly releases this water into their system so as not to shock their system and kill them.
• If the Camel goes long enough without food, the hump will collapse.  It will take the Camel 2-4 months of normal eating for the hump to be completely regenerated.
• Camels have three eyelids.  Two of the eyelids have eye lashes which help protect their eyes from sand.  The third is a very thin lid which works as a sort of “windshield wiper” to clean off their eyes.  It closes/opens from side to side rather than up and down.  It is also thin enough that the Camels can see through it somewhat.  So in a sandstorm or otherwise windy day where sand is being stirred up, they can close that lid to protect their eyes from the sand, but still see where they are going.
• Camels can completely close their nostrils.  This is a useful thing on occasion in sandy environments.
• Adult Camels can weigh anywhere from 700-1500 pounds; attain a height of around 6-7 feet tall; and live up to around 50 years old.
• Pack Camels can comfortably carry around 400-500 pounds as much as 25-40 miles a day.
• A full grown Camel can run 25-35 mph in short bursts.
• Much like goats, Camels will and can eat just about anything.
• There are two “true” types of Camels.  The Arabian Camel, native to Africa, Southwest Asia, and Saudi Arabia; these have one hump.  The other type of Camel, which has two humps, is the Bactrian Camel.  These are found in Central Asia.  Closely related to these, though not considered true Camels, are the four South American Camelids: the Llama, Alpaca, Guanaco, and Vicuña.
• Even though today Camels can only naturally be found in parts of Asia, the Middle East, and Africa, Camels are actually thought to have originated in the Americas around 40 million years ago.  It’s thought that they migrated to Asia shortly before the last Ice Age, though there were still Camels in North America as recent as 15,000 years ago before they became extinct in the Americas.
• Bactrian Camels actually are made to live in extreme cold rather than heat.  They have much thicker foot pads for walking on snow and sharp ice without damaging their feet.  They also have a much more dense coat to help keep themselves warm.  Probably the most amazing thing about this Camel is that they can carry as much as 1000 pounds over short distances.
• Camels aren’t just good for their value as transportation when traveling in the desert.  Their milk and meat are also staple parts of many desert people’s diets.  Their hair is also good for making rugs, ropes, clothes, and even tents.  Their hide also makes good leather, which is particularly valuable for making water skins in the desert.  Their poop also comes out pretty much completely dry and ready to be used as fuel for a fire.  Anyone who’s ever spent any time in a desert knows that is extremely valuable as there often isn’t much around for making fires in deserts and it often gets very cold at night.
• The term “camel” comes from the Arabic  جمل, ǧml which basically means “beauty”.  Apparently whoever named them didn’t get out much.
• Camel milk can be made into yogurt and, with difficulty, butter, but that’s about it.  It’s only been very recently that researchers have been able to make cheese out of Camel milk by adding calcium phosphate and vegetable rennet.  Interestingly, yogurt and butter made from Camels’ milk has a faint greenish tinge.