Who can do without heat? These animals can go without water for years (10 photos)
The origin of so-called complex life is one of the greatest mysteries for science. How could small primitive cells develop into the variety of modern forms that we see today? All textbooks have only one explanation: oxygen. Life began to develop because its level in the atmosphere began to increase rapidly.
Just over half a billion years ago, the first forms of complex life evolved on Earth. Billions of years before, life consisted of simple single-celled organisms. The appearance of animals coincided with a significant increase in atmospheric oxygen. For this reason, it seemed obvious to many scientists that the two events were connected. The conclusion was that the increase in oxygen levels led to the evolution of animals.
Sea sponge Halichondria panicea
(photo by Daniel Mills/SDU).
“But no one had tried to understand how much oxygen such animals need,” says Mills. “So we decided to find out.”
The living creatures that most closely resemble the first inhabitants of our planet are sea sponges. View Halichondria panacea lives just meters from the University of Southern Denmark's marine biology research center in Kärteminne, so Daniel Mills had no trouble obtaining samples for his research.
The researchers kept the sponges in an aquarium and gradually reduced the oxygen levels. Even at a concentration 200 times lower than the original level, the animals survived until the end of the study, that is, another 10 days after oxygen levels stopped falling.
“They continued to breathe and develop even when the oxygen level reached 0.5% of the level that is characteristic of the atmosphere today,” the researcher continues. “This is much lower than we thought was necessary for animal life.”
Experiment at the University of Southern Denmark
(photo by Daniel Mills/SDU).
This raises the question: if low oxygen levels did not prevent the development of animals, then how did they, in principle, affect the first forms of life? Why did life consist only of primitive single-celled bacteria and amoebas for billions of years, and then suddenly complex animals arose?
“Other ecological and evolutionary mechanisms must have come into play,” the researcher said. “Perhaps life remained at the primitive microbial level for so long because it took time to develop the biological mechanism necessary to form an animal. Perhaps the ancient Earth There weren’t enough animals, and many single-celled creatures simply had a hard time developing.”
One reason the early oceans were poor in oxygen may have been due to the abundance of dead microbial forms that consumed oxygen as they decayed. Some geologists, for example, believe that animals such as sponges can purify water. So, it is likely that with their appearance, the level of oxygen in the waters increased, and the evolution of more complex forms that needed more oxygen began.
Temperature limits of life. The need for heat for the existence of organisms is primarily due to the fact that all life processes are possible only against a certain thermal background, determined by the amount of heat and the duration of its action. The temperature of organisms and, as a consequence, the speed and nature of all chemical reactions that make up metabolism depend on the environmental temperature.
The boundaries of the existence of life are temperature conditions under which denaturation of proteins, irreversible changes in the colloidal properties of the cytoplasm, disruption of enzyme activity, and respiration do not occur. For most organisms this temperature range is from 0 to +50°C. However, a number of organisms have specialized enzyme systems and are adapted to active existence at temperatures beyond these limits.
Species whose optimal living conditions are confined to the area of high temperatures are classified as an ecological group thermophiles. Thermophilicity is characteristic of many bacteria that cause self-heating of wet grain, hay, and the cyanobacterium oscilatorium that inhabits the thermal springs of Kamchatka with a water temperature of 85-93°C. Several types of green algae, crustose lichens, and seeds of desert plants located in the upper hot layer of soil successfully tolerate high temperatures (65-80°C). The temperature limit of representatives of the animal world usually does not exceed +55-58 ° C (testate amoebas, nematodes, mites, some crustaceans, larvae of many dipterans).
In many species of plants and animals, cells remain active at temperatures from 0 to -8°C. Such organisms belong to the ecological group cryophiles (Green. Kryos-cold, ice). Cryophilia is characteristic of many bacteria, fungi, lichens, arthropods and other creatures living in the tundra, Arctic and Antarctic deserts, high mountains, cold polar waters, etc.
Poikilothermic and homeothermic organisms. Representatives of most species of living organisms do not have the ability to actively thermoregulate their bodies. Their activity depends primarily on heat coming from outside, and body temperature depends on the ambient temperature. Such organisms are called poikilothermic (ectothermic). Poikilothermy is characteristic of all microorganisms, plants, invertebrates and most chordates.
Only in birds and mammals does the heat generated in the process of intensive metabolism serve as a fairly reliable source of increasing body temperature and maintaining her at a constant level regardless of the ambient temperature. This is facilitated by good thermal insulation created by the coat, dense plumage, and a thick layer of subcutaneous adipose tissue. Such organisms are called homeothermic (endothermic, or warm-blooded). The property of endothermy allows many species of animals (polar bears, pinnipeds, penguins, etc.) to lead an active lifestyle at low temperatures.
A special case of homoYothermy - heterothermy- characteristic of animals that hibernate or become temporarily torpid during unfavorable periods of the year (gophers, hedgehogs, bats, dormice, etc.). In an active state, they maintain a high body temperature, and in the case of low body activity, a lower one, which is accompanied by a slowdown in metabolic processes and, as a consequence, low heat transfer.
Temperature adaptation of plants. The optimal temperature for most terrestrial plants is +25-30°C, and for heat-demanding plants such as corn, beans, soybeans and other species of tropical and subtropical origin, it is +30-35°C. It should be borne in mind that for each phase and stage of plant development there is both an optimal temperature regime and upper and lower limits.
When the plant is exposed to high temperatures severe dehydration and desiccation occurs, burns, destruction of chlorophyll, irreversible respiratory disorders, and finally, thermal denaturation of proteins, coagulation of the cytoplasm and death.
Plants are able to withstand the dangerous influence of extremely high temperatures due to increased transpiration, accumulation of protective substances (mucus, organic acids, etc.) in the cytoplasm, shifts in the temperature optimum of the activity of the most important enzymes, transition to a state of deep dormancy, as well as their occupation of temporary habitats protected from strong overheating This means that for some plants the entire growing season is shifted to a season with more favorable thermal conditions. Thus, in deserts and steppes there are many species of plants that begin their growing season very early in the spring and manage to finish it before the onset of the summer heat. They survive these conditions in a state of summer dormancy - the seeds have already ripened or underground organs have appeared - bulbs, tubers, rhizomes (tulips, crocuses, bluegrass bulbous, etc.)
The morphological adaptations that prevent overheating are essentially the same ones that serve the plant to reduce the flow of solar radiation. This is a shiny surface and dense pubescence, giving the leaves a light color and increasing the reflection of solar radiation, the vertical position of the leaves, the folding of leaf blades (in cereals), the reduction of leaf surface, etc. These same structural features of plants at the same time provide them with the ability to reduce water loss. Thus, the complex effect of environmental factors on the body is reflected in the complex nature of adaptation.
Danger of low temperatures for plants it comes down to the fact that water freezes in the intercellular spaces and cells and, as a result, dehydration and mechanical damage to the cells occurs, followed by coagulation of proteins and destruction of the cytoplasm. Cold inhibits the processes of plant growth, photosynthesis, and chlorophyll formation, reduces the energy efficiency of respiration, and sharply slows down the rate of development.
To withstand the unfavorable conditions of the cold period of the year, plants are prepared in advance: their leaves fall, and in herbaceous forms - above-ground organs, pubescence of the bud scales occurs, winter tarring of the buds (in conifers), the formation of a thick cuticle, a thickened cork layer, etc.
Among the morphological adaptations of plants to life in cold latitudes, small size (dwarfism) and special growth forms are important. The height of dwarf plants (dwarf birch, dwarf willows, etc.) usually corresponds to the depth of the snow cover under which the plants overwinter, since all parts protruding above the snow die from freezing. Similar protection from the cold is also typical for creeping forms - dwarf elfin trees (cedar, juniper, mountain ash, etc.) and cushion-shaped forms, formed as a result of increased branching and extremely slow growth of shoots.
An example of the physiological adaptation of plants that prevents the freezing of water in the intercellular spaces and cells, their dehydration and mechanical damage, is an increase in the concentration of soluble carbohydrates in cell sap, which helps to lower the freezing point.
Temperature adaptation of animals. Compared to plants, animals have a more diverse ability to adapt to different temperatures. Typically, there are three main ways of temperature adaptation: 1) chemical thermoregulation (increased heat production in response to a decrease in environmental temperature); 2) physical thermoregulation (changes in the level of heat transfer, the ability to retain heat or, conversely, dissipate its excess); 3) behavioral thermoregulation (avoiding unfavorable temperatures by moving in space or changing behavior in a more complex way).
Poikilothermic animals, unlike homeothermic ones, are characterized by a lower metabolic rate even at the same body temperature. For example, a desert iguana at a temperature of +37°C consumes 7 times less oxygen than rodents of the same mass. For this reason, little heat is generated in the body of ioiikilothermic animals, and, as a consequence, the possibilities of chemical and physical thermoregulation are negligible. Their main way of regulating body temperature is through behavioral features - changing posture, actively searching for favorable climatic conditions, changing habitats, independently creating the desired microclimate (building nests, digging holes, etc.). For example, in extreme heat, animals hide in the shade, hide in burrows, and some species of desert lizards and snakes climb bushes, avoiding contact with the hot surface of the soil.
Some poikilothermic animals are able to maintain optimal body temperature through muscle activity. Thus, bumblebees warm up their bodies by activating muscle contractions (shivering) to +32 and 33°C, which gives them the opportunity to take off and feed in cool weather.
Homeothermy developed from poikilothermy by intensifying metabolic processes and improving methods for regulating the heat exchange of animals with the environment. Effective regulation of heat input and output allows adult homeothermic animals to maintain a constant optimal body temperature at all times of the year.
Due to the high metabolic rate and the production of a significant amount of heat, homeothermic animals are distinguished by a high ability for chemical thermoregulation, which is especially important when exposed to cold. However, maintaining temperature due to increased heat production requires a large expenditure of energy, so animals in the cold season need a lot of food or spend a lot of fat reserves accumulated earlier. For example, birds that remain for the winter are afraid not so much of frost as of lack of food. If there is a good harvest of spruce and pine seeds, crossbills even hatch chicks in winter. But with a lack of food in winter, this type of thermoregulation is environmentally unprofitable, and therefore is poorly developed in arctic foxes, walruses, seals, polar bears and other animals living in the Arctic Circle.
Physical thermoregulation, which ensures adaptation to cold not due to additional heat production, but due to its preservation in the animal’s body, is carried out by reflex narrowing and dilating of the blood vessels of the skin, changing its thermal conductivity, changing the thermal insulating properties of fur and feathers, and regulating evaporative heat transfer.
The thick fur of mammals and the feather cover of birds make it possible to maintain a layer of air around the body with a temperature close to the body temperature of the animal, and thereby reduce heat transfer to the external environment. Inhabitants of cold climates have a well-developed layer of subcutaneous fatty tissue, which is evenly distributed throughout the body and is a good heat insulator.
An effective mechanism for regulating heat exchange is also the evaporation of water through sweating or through the moist membranes of the oral cavity (for example, in dogs). Thus, a person in extreme heat can secrete more than 10 liters of sweat per day, thereby helping to cool the body.
Behavioral methods of regulating heat exchange in homeothermic animals are the same as in poikilothermic animals.
Thus, the combination of effective methods of chemical, physical and behavioral thermoregulation allows warm-blooded animals to maintain their thermal balance against the background of wide fluctuations in environmental temperature.
For those who are not interested in animals, but are looking for where to buy a cheaper New Year's gift, a Groupon promotional code will definitely come in handy.Some organisms, when compared with others, have a number of undeniable advantages, for example, the ability to withstand extremely high or low temperatures. There are a lot of such hardy living creatures in the world. In the article below you will get acquainted with the most amazing of them. They, without exaggeration, are able to survive even in extreme conditions.
1. Himalayan jumping spiders
Bar-headed geese are known to be among the highest flying birds in the world. They are capable of flying at an altitude of more than 6 thousand meters above the ground.
Do you know where the highest populated area on Earth is located? In Peru. This is the city of La Rinconada, located in the Andes near the border with Bolivia at an altitude of about 5100 meters above sea level.
Meanwhile, the record for the highest living creatures on planet Earth went to the Himalayan jumping spiders Euophrys omnisuperstes ("standing above everything"), which live in nooks and crannies on the slopes of Mount Everest. Climbers found them even at an altitude of 6,700 meters. These tiny spiders feed on insects that are blown to mountain peaks by strong winds. They are the only living creatures that permanently live at such a great height, not counting, of course, some species of birds. It is also known that Himalayan jumping spiders are able to survive even in conditions of lack of oxygen.
2. Giant Kangaroo Jumper
When we are asked to name an animal that can survive without drinking water for long periods of time, the first thing that comes to mind is the camel. However, in the desert without water it can survive no more than 15 days. And no, camels do not store water reserves in their humps, as many people mistakenly believe. Meanwhile, there are still animals on Earth that live in the desert and are able to live without a single drop of water throughout their entire lives!
Giant kangaroo hoppers are relatives of beavers. Their lifespan ranges from three to five years. Giant kangaroo jumpers receive water along with their food, and they feed mainly on seeds.
Giant kangaroo jumpers, as scientists note, do not sweat at all, so they do not lose, but, on the contrary, accumulate water in the body. You can find them in Death Valley (California). Giant kangaroo hoppers are currently endangered.
3. Worms that are resistant to high temperatures
Since water conducts heat from the human body about 25 times more efficiently than air, a temperature of 50 degrees Celsius in the depths of the sea will be much more dangerous than on land. This is why bacteria thrive underwater, and not multicellular organisms that cannot withstand too high temperatures. But there are exceptions...
The marine deep-sea annelids Paralvinella sulfincola, which live near hydrothermal vents on the bottom of the Pacific Ocean, are perhaps the most heat-loving living creatures on the planet. The results of an experiment conducted by scientists with heating an aquarium showed that these worms prefer to settle where the temperature reaches 45-55 degrees Celsius.
4. Greenland shark
Greenland sharks are among the largest living creatures on planet Earth, but scientists know almost nothing about them. They swim very slowly, on par with an ordinary amateur swimmer. However, it is almost impossible to see Greenland sharks in ocean waters, since they usually live at a depth of 1200 meters.
Greenland sharks are also considered the most cold-loving creatures in the world. They prefer to live in places where the temperature reaches 1-12 degrees Celsius.
Greenland sharks live in cold waters, which means they have to conserve energy; this explains the fact that they swim very slowly - at a speed of no more than two kilometers per hour. Greenland sharks are also called “sleeper sharks.” They are not picky about food: they eat whatever they can catch.
According to some scientists, the life expectancy of Greenland sharks can reach 200 years, but this has not yet been proven.
5. Devil's worms
For several decades, scientists thought that only single-celled organisms could survive at very great depths. It was believed that multicellular life forms could not live there due to lack of oxygen, pressure and high temperatures. However, just recently, researchers discovered microscopic worms at a depth of several thousand meters from the surface of the earth.
The nematodes Halicephalobus mephisto, named after a demon from German folklore, were discovered by Gaetan Borgoni and Tallis Onstott in 2011 in water samples taken at a depth of 3.5 kilometers in a cave in South Africa. Scientists have found that they show high resistance to various extreme conditions, like those roundworms that survived the Columbia space shuttle disaster that occurred on February 1, 2003. The discovery of devil worms could help expand the search for life on Mars and any other planet in our Galaxy.
6. Frogs
Scientists have noticed that some species of frogs literally freeze with the onset of winter and, thawing in the spring, return to a full life. There are five species of such frogs in North America, the most common being Rana sylvatica, or wood frog.
Wood frogs do not know how to burrow into the ground, so with the onset of cold weather they simply hide under fallen leaves and freeze, like everything around them. Inside the body, their natural “antifreeze” defense mechanism is triggered, and they, like a computer, go into “sleep mode”. The glucose reserves in the liver largely allow them to survive the winter. But the most amazing thing is that Wood Frogs demonstrate their amazing ability both in the wild and in laboratory conditions.
7. Deep Sea Bacteria
We all know that the deepest point of the World Ocean is the Mariana Trench, which is located at a depth of more than 11 thousand meters. At its bottom, the water pressure reaches 108.6 MPa, which is approximately 1072 times greater than normal atmospheric pressure at the level of the World Ocean. A few years ago, scientists using high-resolution cameras placed in glass spheres discovered giant amoebas in the Mariana Trench. According to James Cameron, who led the expedition, other life forms also flourish there.
Having studied water samples from the bottom of the Mariana Trench, scientists discovered a huge number of bacteria in it, which, surprisingly, actively multiplied, despite the great depth and extreme pressure.
8. Bdelloidea
Rotifers Bdelloidea are small invertebrate animals that are usually found in fresh water.
Representatives of the rotifers Bdelloidea lack males; populations are represented only by parthenogenetic females. Bdelloidea reproduce asexually, which scientists believe negatively affects their DNA. What is the best way to overcome these harmful effects? Answer: eat the DNA of other life forms. Thanks to this approach, Bdelloidea has evolved an amazing ability to withstand extreme dehydration. Moreover, they can survive even after receiving a dose of radiation that is lethal for most living organisms.
Scientists believe that Bdelloidea's ability to repair DNA was originally given to them to survive in high temperatures.
9. Cockroaches
There is a popular myth that after a nuclear war, only cockroaches will remain alive on Earth. These insects can go for weeks without food or water, but even more amazing is the fact that they can live many days after losing their heads. Cockroaches appeared on Earth 300 million years ago, even earlier than dinosaurs.
The hosts of “Mythbusters” in one of the programs decided to test cockroaches for survivability in the course of several experiments. First, they exposed a certain number of insects to 1,000 rads of radiation, a dose capable of killing a healthy person in a matter of minutes. Almost half of them managed to survive. After the MythBusters increased the radiation power to 10 thousand rads (as during the atomic bombing of Hiroshima). This time, only 10 percent of the cockroaches survived. When the radiation power reached 100 thousand rads, not a single cockroach, unfortunately, managed to survive.
10. Tardigrades
Microscopic aquatic invertebrate animals, tardigrades, are perhaps the hardiest living things on planet Earth. These, to some extent, cute creatures are able to survive everything: cold, heat, high pressure and even powerful radiation. Tardigrades are able to survive in extreme conditions by entering a state of dehydration that can last for decades! They return to full existence immediately after they find themselves in the water.
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It is quite difficult for the average person to survive for several days without water, but some animals can survive without it for years.
According to NASA data, 2016 may be considered the hottest year on the planet. And such high temperatures lead to droughts. For example, the eastern Mediterranean is experiencing its worst drought in 900 years.
Water shortage leads to losses among people and animals. Typically, we lose four to nine glasses of water per day through sweat, urine and breathing. If you don't drink enough water to quench your thirst, the costs may be too high. Symptoms of dehydration range from fatigue, headaches and muscle weakness to increased heart rate and eventual loss of consciousness.
Many animals also suffer without water. But some, especially those that live in dry seasonal environments, can be quite resourceful when it comes to coping with drought.
Savings for a dusty day
No desert home would be complete without a water storage tank, but for some animals it is internal.
Turtles, including desert and giant tortoises in the Galapagos Islands, store water in their bladders. When it rains or when they have access to greenery, turtles fill their bladder with water. In dry times, they can extract water from it thanks to the permeable walls of the organ.
But the Australian water-retaining frog stores water in its gills, their tissues, and also in the bladder. This bloated amphibian can store enough water to double its weight. Once it is completely filled with water, it can live for 5 years without replenishing these reserves.
Other desert inhabitants use external water storage tanks in the form of frogs. Snakes, birds, large frogs, crocodiles and wild dogs can use them. During the dry season, the Tiwi aboriginals dig up the frogs and squeeze the water out of them.
Slime coat
Other creatures suffering from drought have found a way to protect their bodies so as not to lose water from them. The deserts of North America are home to spadefoot toads, which use their claws to dig deep burrows underground. There they hide for three quarters of the year. While in these burrows, toads produce a mucous membrane to conserve water. They appear on the surface 10 months later, when they feel the strong sound of rain on the surface.
Some tree frogs also reduce water loss by secreting an impenetrable waxy material on their skin. In South and Central America, tree wax frogs look for a safe place and then begin to press on the throat and abdominal walls. At the same time, with the help of their paws, they rub lipid secretions throughout the body.
Lungbreathing creatures
African lungfishes have taken this approach even further. It is an eel-like fish that lives in shallow waters and swamps. But when the water dries up, these aquatic creatures turn into land-dwellers who breathe air and hear through the atmosphere rather than water. All lungfish have a bladder that turns into “lungs” and highly developed ears, similar to those of land animals.
During the dry season, these fish dig deep burrows in the dried mud using their pelvic fins and then secrete a coating of mud to keep water loss to a minimum. While wearing this sticky garment, lungfish can "sleep" in a state of suspended animation for three to five years, without the need to eat or drink. They wake up only when fresh water becomes available.
Forget about drinking, just eat
For desert animals, food is often one of the best sources of water, and food can survive when there is no moisture. North American marsupial rats and mice collect seeds when conditions are moist and plants are abundant. They live off these seeds for the rest of the year. These rodents spend hot, dry days in their burrows and only come out at night. Because the seeds they store are high in carbohydrates, rodents gain energy and metabolic water so they don't need to drink.
While rodents rely on carbohydrate metabolism, larger mammals, such as camels and oryxes, rely more on fat metabolism. When an animal breaks down one gram of fat, 1.12 milliliters of water is released. Therefore, camels do not store water in their humps, but fat reserves.
If fat is such a good source of water, you might ask why there aren't huge numbers of animals in the desert that can survive on their own reserves of fat. However, if animals have fat distributed evenly throughout their body, they will also suffer because it is a good insulator that traps body heat. This means that fat deposits should be stored in one or two places on the body.
Leak installation
While insects and cacti can provide a meager supply of water, most animals survive by using it sparingly. These calculating creatures have developed ingenious ways to stop the slow loss of moisture caused by sweating, breathing, urination and excretion.
For example, marsupial rats have pouches near their cheeks that are completely devoid of salivary glands. These dry "grocery bags" are located in folds, separate from the rest of the mouth, so that the rodents do not waste a drop of drool while carrying their supplies.
While sweating and panting can help desert animals cool their bodies, it also results in costly water loss. To get around this problem, camels have fewer sweat glands and are unable to pant. They allow their body temperature to fluctuate by 6 degrees throughout the day. A person, for example, spends a lot of energy to maintain body temperature at the same level. But camels were able to relax the limits of body temperature regulation. This is a great way to reduce your dependence on water.
How to breathe
Moreover, camels, ostriches and marsupial rats have specialized respiratory systems that help them exhale less air.
The air in the lungs of marsupial rats is always warm and saturated with water, but the tips of their noses are cold. In the middle there is a long and winding passage for air. As air passes from the lungs into the atmosphere, the water vapor cools and condenses on the lining of the nose. After condensation, the water is returned back rather than wasted into the atmosphere.
When the rat gets into its hole, it exhales this water vapor and it becomes trapped there. Then the rat breathes it again.
Catch it if you can
While some desert animals are adapted to conserve water, some find a way to catch every drop of it.
For example, the thorny devil, who lives in the Australian outback, has the ability to drink using his own skin. The animal is covered with spines, between which there are drainage grooves. They are able to absorb water like blotting paper, especially at night when dew settles on animals and plants. All the grooves lead directly into the mouth of the lizard, which sucks drops of water from its body.
Sand grouse can also absorb small amounts of water and store it in their feathers. This is extremely important, since they often nest 50 kilometers from water sources.
It is quite difficult for the average person to survive for several days without water, but some animals can survive without it for years.
According to NASA data, 2016 may be considered the hottest year on the planet. And such high temperatures lead to droughts. For example, the eastern Mediterranean is experiencing its worst drought in 900 years.
Life without water
Water shortage leads to losses among people and animals. Typically, we lose four to nine glasses of water per day through sweat, urine and breathing. If you don't drink enough water to quench your thirst, the costs may be too high. Symptoms of dehydration range from fatigue, headaches and muscle weakness to increased heart rate and eventual loss of consciousness.
Many animals also suffer without water. But some, especially those that live in dry seasonal environments, can be quite resourceful when it comes to coping with drought.
Savings for a dusty day
No desert home would be complete without a water storage tank, but for some animals it is internal.
Turtles, including desert and giant tortoises in the Galapagos Islands, store water in their bladders. When it rains or when they have access to greenery, turtles fill their bladder with water. In dry times, they can extract water from it thanks to the permeable walls of the organ.
But the Australian water-retaining frog stores water in its gills, their tissues, and also in the bladder. This bloated amphibian can store enough water to double its weight. Once it is completely filled with water, it can live for 5 years without replenishing these reserves.
Other desert inhabitants use external water storage tanks in the form of frogs. Snakes, birds, large frogs, crocodiles and wild dogs can use them. During the dry season, the Tiwi aboriginals dig up the frogs and squeeze the water out of them.
Slime coat
Other creatures suffering from drought have found a way to protect their bodies so as not to lose water from them. The deserts of North America are home to spadefoot toads, which use their claws to dig deep burrows underground. There they hide for three quarters of the year. While in these burrows, toads produce a mucous membrane to conserve water. They appear on the surface 10 months later, when they feel the strong sound of rain on the surface.
Some tree frogs also reduce water loss by secreting an impenetrable waxy material on their skin. In South and Central America, tree wax frogs look for a safe place and then begin to press on the throat and abdominal walls. At the same time, with the help of their paws, they rub lipid secretions throughout the body.
Lungbreathing creatures
African lungfishes have taken this approach even further. It is an eel-like fish that lives in shallow waters and swamps. But when the water dries up, these aquatic creatures turn into land-dwellers who breathe air and hear through the atmosphere rather than water. All lungfish have a bladder that turns into “lungs” and highly developed ears, similar to those of land animals.
During the dry season, these fish dig deep burrows in the dried mud using their pelvic fins and then secrete a coating of mud to keep water loss to a minimum. While wearing this sticky garment, lungfish can "sleep" in a state of suspended animation for three to five years, without the need to eat or drink. They wake up only when fresh water becomes available.
Forget about drinking, just eat
For desert animals, food is often one of the best sources of water, and food can survive when there is no moisture. North American marsupial rats and mice collect seeds when conditions are moist and plants are abundant. They live off these seeds for the rest of the year. These rodents spend hot, dry days in their burrows and only come out at night. Because the seeds they store are high in carbohydrates, rodents gain energy and metabolic water so they don't need to drink.
While rodents rely on carbohydrate metabolism, larger mammals, such as camels and oryxes, rely more on fat metabolism. When an animal breaks down one gram of fat, 1.12 milliliters of water is released. Therefore, camels do not store water in their humps, but fat reserves.
If fat is such a good source of water, you might ask why there aren't huge numbers of animals in the desert that can survive on their own reserves of fat. However, if animals have fat distributed evenly throughout their body, they will also suffer because it is a good insulator that traps body heat. This means that fat deposits should be stored in one or two places on the body.
Leak installation
While insects and cacti can provide a meager supply of water, most animals survive by using it sparingly. These calculating creatures have developed ingenious ways to stop the slow loss of moisture caused by sweating, breathing, urination and excretion.
For example, marsupial rats have pouches near their cheeks that are completely devoid of salivary glands. These dry "grocery bags" are located in folds, separate from the rest of the mouth, so that the rodents do not waste a drop of drool while carrying their supplies.
While sweating and panting can help desert animals cool their bodies, it also results in costly water loss. To get around this problem, camels have fewer sweat glands and are unable to pant. They allow their body temperature to fluctuate by 6 degrees throughout the day. A person, for example, spends a lot of energy to maintain body temperature at the same level. But camels were able to relax the limits of body temperature regulation. This is a great way to reduce your dependence on water.
How to breathe
Moreover, camels, ostriches and marsupial rats have specialized respiratory systems that help them exhale less air.
The air in the lungs of marsupial rats is always warm and saturated with water, but the tips of their noses are cold. In the middle there is a long and winding passage for air. As air passes from the lungs into the atmosphere, the water vapor cools and condenses on the lining of the nose. After condensation, the water is returned back rather than wasted into the atmosphere.
When the rat gets into its hole, it exhales this water vapor and it becomes trapped there. Then the rat breathes it again.
Catch it if you can
While some desert animals are adapted to conserve water, some find a way to catch every drop of it.
For example, the thorny devil, who lives in the Australian outback, has the ability to drink using his own skin. The animal is covered with spines, between which there are drainage grooves. They are able to absorb water like blotting paper, especially at night when dew settles on animals and plants. All the grooves lead directly into the mouth of the lizard, which sucks drops of water from its body.
Sand grouse can also absorb small amounts of water and store it in their feathers. This is extremely important, since they often nest 50 kilometers from water sources.
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