Camels. With their long, slender legs, their necks that drop and rise again to meet their heads and, of course, their famous humpbacked loin, with one or two humps, it’s very difficult to mistake them for any other animal.
Actually, we’re talking about three animals, not just one. The most common type of so-called “camel” is the dromedary, with only one hump and also known as the “Arabian camel”. They make up approximately 60% of the world’s camel population and have been domesticated for more than 3.000 years.
The second species, officially called “bactrian camel”, is known in Portuguese as just “camel” and has two humps. They were domesticated even before the dromedaries, between 4. and 6.000 years ago, and are native to Central Asia.
And there are also wild camels, much like camels bacterial, as they also have two humps, and whose scientific name is Camelus ferus. This species lives in the Gobi Desert, Asia, being found in Mongolia and northwestern China. Unlike their cousins, this type of camel has never been domesticated.
Surprisingly, some survive without difficulty by drinking water with a higher concentration of salt than seawater. Not only are they different animals, but with less than a thousand representatives of their species, they are among the most endangered large mammals on the planet.
The question that remains…
What, after all, exists inside the humps? We often hear that these humps would be full of water, and this is what would allow a camel to survive long periods of time in the desert.
As interesting as this may sound, this is a myth, completely false. The humps are not actually filled with water, but with fat.
How long a camel can survive with its stored fat depends on how active it is and the climate. Hump size may vary depending on your diet. When food is scarce, the body consumes the fat stored in the hump, which causes it to tip over and fall to the ground.
Store fat on your back instead of in layers all over the body, helps you to avoid overheating, with the added benefit that these humps offer some protection and shade from direct sunlight.
Camels can survive in some of the most hostile and extreme regions on the planet. In the desert, temperatures can range from scorching 41º C to freezing cold -30º C.
To help you cope with these extreme temperature changes, the bacterial camel’s fur (two humps) gets thicker in winter.
A camel can go a whole week without water—and survive even longer without knowing it if it isn’t working hard. They withstand a weight loss of about 4%, which for an adult bacterial translates to approximately 13 kg.
They can, however, also absorb water like a sponge. A thirsty camel can drink 130 liters in just 13 minutes — that is, 13 liters each 60 seconds.
Another important adaptation of camels is their ability to limit sweating. One might imagine that the last thing an animal living in extreme heat needs is a fur coat. However, if a camel lost its thick fur, it would consume 41% more water.
Hair provides a great isolation. In addition to being useful on cold desert nights, during the day, when outside temperatures are much higher than that of the camel’s body, this blanket prevents heat from penetrating your body.
In many ways, the camel’s secret lies in its ability to keep “cool” and barely sweat.
During the night, its body temperature fluctuates around 41 º C. This gives the camel a kind of shock absorber for that it can withstand more heat the next day.
The camel only needs to sweat when its body temperature reaches about 34º C. With his fur coat acting as a barrier against external heat, he may only sweat for a couple of hours, later in the day, which means considerable water savings.
In fact, in a hot, dry desert, a camel that can weigh at least five times more than a human being uses only a quarter of a liter of water every hour. ra.
And here’s a curious fact: many of these adaptations to extreme weather come from their arctic ancestors. Modern camels evolved at the North Pole.
Colds like a camel
Camels’ amazing evolutionary strategies for keeping cool attracted a lot the interest of scientists who are looking for ways to keep food and medicine cool, for long periods of time, without a refrigerator or any form of external energy.
Achieving this would undoubtedly bring enormous benefits to preserve such products and extend their shelf life.
But not just that. According to the International Energy Agency, world demand for energy for cooling —measured by the demand for refrigerators, freezers and air conditioners—is expected to triple by up to 250.
As the negative impact of this increase in climate change would be enormous, there is a need to develop new ways to prevent products from heating up without the use of electricity.
These methods are known as passive cooling . We ourselves experienced a great example of passive cooling: when we get hot and start to sweat, the evaporation of our sweat cools our body.
One of the most promising solutions is based on the evaporation of hydrogels.
What is a hydrogel?
A hydrogel is a polymeric material, which are those composed of long repeated chains of molecules and which, depending on the molecules, have different properties.
The properties of hydrogels are that, in addition to absorbing and retaining a lot of water, they can release it through evaporation, without the need for a source of external energy.
This is why scientists in search of passive cooling methods have been so interested in them for quite some time.
The challenge, however, always it’s been like making this effect last for longer periods of time—and camels could have the solution.
A team led by Jeffrey Grossman at Mas Institute of Technology Sachusetts (MIT), in the United States, found his inspiration in camels.
Combining a layer of hydrogel with a thin layer of another gel called aerogel —or icy smoke—, composed by
,50% and 99,90% air and which is an insulating material, the group imitated the camels’ biological cooling system.
To understand better, it’s two layers. The hydrogel one, underneath, is like the sweat gland on a camel. It allows the water to evaporate and provides a cooling effect.
The airgel layer above plays the same role as a camel’s fur, providing crucial insulation and preventing heat from the surrounding area to pass through, while allowing the water vapor from the hydrogel to escape, as it is highly porous.
One centimeter of protection
*)By obtaining evaporation and insulation at the same time, the cooling period is significantly extended. This two-layer gel combination, or bilayer as it is technically called, is only one centimeter thick.
The MIT team tested its bilayer in the laboratory using a special chamber, with controlled temperature and humidity, and found that it was able to cool an object to 7°C less than the temperature around it.
Compared to a single layer of hydrogel, the length of time that the bilayer could keep an object cool increased by 250%. As Grossman pointed out, this means more than 130 hours, or ten days of cooling.
The team said their project could also help cool buildings and, with that, reduce the total energy consumption.
The next step of the group of scientists is to make the material more scalable. In other words, they need to find a way to more easily produce it in larger sizes and quantities.
When considering how often we need to transport food and medicine, sometimes to places where it exists. little or no access to coolers or even power, it’s clear the value of a passive cooling system like this. The Covid pandemic-19, with the need to transport vaccines at low temperatures, reminded us once again of this common challenge.
A solution like the one sought by the MIT team would be fantastic for the environment, with the potential to become a technology that saves lives. All thanks to the camel, this curious creature that inhabits the desert.
This article is an adaptation of the episode “Camel and cold remedies”, from the series “ Animals That Made Us Smarter”, from the BBC World Service.