How do camels survive in deserts?

Camels are part of a group known as camelids. This makes them close relatives of llamas, alpacas, guanacos and vicuñas, which are all native to South America.

There are three species of camels living today and most are domesticated. The one-humped dromedary (Camelus dromedarius) is found in dry regions in Africa and Asia, including the Sahara Desert and Middle East. The domestic Bactrian camel (Camelus bactrianus) is found across Central Asia and the wild Bactrian camel (Camelus ferus) is found in remote parts of Mongolia and China and is critically endangered. Domestic and wild Bactrian camels have two humps.

Why do camels have humps?

Camels' humps are often associated with these animals' ability to go for long periods without taking a drink. But they don't store water in them. Instead, their humps are made of fat. Camels are generally found in areas with limited water and vegetation. Their fat store can be converted to energy when they don’t have access to the resources they need to survive.

To last for prolonged periods in dry areas, camels have also adapted to minimise the amount of water they lose. For example, camels have thick, syrupy urine and their faeces are so dry that they can be used as fire starters.

A camel can also use its nose as a dehumidifier. When we breathe, the air we exhale is at body temperature and we lose water in it as vapour. But when air passes out over a camel's mucous membranes it is cooled and the water vapour is removed and reabsorbed into the body. This saves them from losing water with each breath.

Camels can withstand a loss of up to 30% of their bodyweight in water, which is far more than most other mammals could survive. But they cannot go without water forever. When camels can drink, they take in vast amounts of liquid quite quickly, but they don't store it for later, so it's just enough to rehydrate themselves.

Extreme heat and cold are no sweat for a camel

Camels are adapted to live in extreme environments, both hot and cold.

Unlike a lot of other mammals, most of a camel's fat is stored in its humps, which allows for better thermoregulation. It makes it easier for them to release heat from their bodies in hot weather.

Camels rarely sweat. They are much better than us at tolerating hot weather. Their body temperature fluctuates, rising in the day with the increased environmental temperature and falling at night when it is cooler. It might seem strange that camels are furry when they can be found in extremely hot deserts, but their coats actually serve as insulation, protecting them from the heat. In fact, shorn camels tend to sweat more.

Desert sand can be scorching, so camels have leathery, heat-resistant pads on their feet, knees, elbows and sternum so they can lie down without getting burnt. They also lack a stifle fold. In other animals, this is the skin that stretches from the abdomen to the thighs. Camels don't have this, so when they are lying down, air can continue to circulate under their bodies. 

But while camels are often thought of as being found exclusively in hot areas, some can also be found in much cooler regions.

Bactrian camels in Central Asia, for example, face freezing winters and scorching summers. They are suitably adapted though, with thick fur keeping them warm when it gets cold. This coat quickly sheds when their environment starts to warm up again. Camels have historically been suited to colder weather, with evidence of now extinct species found in the Arctic Circle.

How do camels walk on sand without sinking?

Sand and other soft surfaces can be tricky to walk on. Sinking into the ground means it takes more effort and energy to take each step.

Camels can weigh up to 1,000 kilograms, with males often much larger and heavier than females. Rather than small hooves, camels are equipped with wide snowshoe-like feet with two toes. The large size and round shape of their feet help camels to distribute their weight, preventing them from sinking. 

Why do camels have long eyelashes?

While you might not spend too much time thinking about your eyelashes, these little hairs play a very important role as your eyes' first line of defence. Eyelashes keep dust and dirt away from our sensitive eyeballs.

This function is particularly important for camels who often live in dry and dusty environments. Their eyelashes are often noted for being particularly long. Research has found that there is an ideal ratio for optimal eyelashes and that tends to be one third the width of the eye they protect. Camels have much larger eyes than us, hence the luscious length of their lashes.  

But if a camel's long eyelashes and bushy brows aren't enough and debris does get into their eyes, these animals have a third eyelid that can sweep it out like a windscreen wiper. This thin structure is known as a nictitating membrane. A number of other animals have functioning third eyelids, such as cats, seals, birds and reptiles.

Camels can also stop sand and dirt from getting in their noses by fully closing their nostrils.

What do camels eat?

Desert environments can offer limited food options for herbivorous camels. Dromedaries and Bactrian camels mostly feed on fibre-rich thorny plants, with access to some shrubs, trees, herbs and grasses.

But camels can happily munch on prickly plants. Their lips and tongues are tough, and they have mouths lined with firm papillae (fleshy protrusions). These help camels manipulate and swallow their food, but also prevent it from scraping, poking or otherwise injuring their mouths. 

When a camel swallows food, it passes into a chamber of their stomach called the rumen, where it begins to ferment and soften with the help of microbes. The animal then regurgitates this material, which is known as cud, and carries on chewing it before it can be swallowed again and properly digested.

Though camels ruminate, they don't have the typical four-chambered stomach seen in true ruminants like cows. Instead, camels are sometimes called pseudoruminants.