Why are camels called "ships in the desert"?
Characteristics of living environment
land
The soil in arid areas contains a lot of minerals and little organic fertilizer. Repeatedly storing water to put some
The soil turned into a salt layer. Calcium carbonate precipitated from salt solution can make sandstone into "cement" with a thickness of 50 meters.
Nitrite layer is a common reddish brown to white layer in desert soil. Nitrite layer is generally massive or wrapped around mineral particles, which is formed by the complex interaction between water and carbon dioxide. Carbon dioxide comes from plant roots or by-products of organic matter decay.
Camels in the desert Most desert plants are drought-resistant or salt-tolerant plants. Some store water in roots, stems and leaves; Some have a huge rhizome system, which can directly reach the groundwater layer, block the soil and prevent soil erosion; Some have large stems and leaves, which can reduce wind speed and preserve sand.
Plants in the desert are sparsely distributed, but there are many varieties. The cactus in the desert of the southwestern United States can live for 200 years, growing to 15 meters and 10 tons, making it a tree in the desert. The cylindrical cactus grows slowly, 9 years later 15cm, the first branch in 75 years. Because of its huge size, it seems that there are many cacti in the desert. In fact, peas and sunflowers can also live in dry and hot areas. Haloxylon ammodendron is also a unique shrub plant in the desert, with an average height of 2-3m and some as high as 5 m. It is called the "king of desert vegetation" and its life span can reach 100 years. In spring, grass or shrubs usually grow in cold deserts.
waterhead
It rains occasionally in the desert, and it is often a storm. There was a record of three hours and 44 millimeters of precipitation in the Sahara desert. At this time, the normally dry river will be filled with water quickly, which is prone to floods.
Although it seldom rains in the desert, it often gets water from rivers flowing down from nearby mountains. These rivers usually carry a lot of soil and will dry up after a day or two in the desert. Only a few great rivers in the world flow through deserts, such as the Nile in Egypt, the Yellow River in China and the Colorado River in the United States.
If there is enough water, a seasonal lake will form in the desert, which is generally shallow and salty. Because the bottom of the lake is very flat, the wind will blow the lake to dozens of square kilometers. When the small lake dries up, it will leave a salt flat. There are hundreds of such salt flats in the United States, most of which are the remains of the Great Lakes during the Ice Age before 12000, the most famous of which is the Great Salt Lake in Utah. Flat salt flats are good places for racing cars, airstrips and spacecraft to land.
Camels in the desert
Mineral storage
Some minerals are formed in arid areas. The water on the ground dissolves minerals and then concentrates them near the surface of groundwater, making it an easy-to-develop storage place.
There are many minerals, such as gypsum and salt. Substances (including sodium nitrate, sodium chloride and borate) left on the surface of salt flats after water evaporation. Boron extracted from borax and other borates is the basic component of glass, ceramics, enamel, pesticide, water softener and western medicine.
The value of minerals produced by Lake Searle is over 654.38 billion dollars.
The Atacama desert in South America produces a large amount of sodium nitrate, which was mined in the19th century and used for explosives and fertilizers. More than 3 million tons were produced during World War II.
transport
The United States, Chile, Peru and Iran produce copper. Australia produces iron, lead and zinc. Turkey produces chromite. Australia and the United States have gold, silver and uranium reserves.
The advancing camel team
Non-metallic substances, such as beryllium, mica, lithium, clay, light stone and metal slag, also appear in arid areas.
Most of the world's largest oil reserves are in desert areas, but these reserves are not caused by dry climate. Before these areas became deserts, they were shallow seas, and oil was formed for marine benthos. The most famous oil producers are Saudi Arabia, Iran, Iraq and other places.
Camels are hungry, thirsty, docile, fearless of sandstorms and good at walking in the desert. They are recognized as desert boats in the world and indispensable means of transportation in desert areas.
brief introduction
There are two kinds of camels: unimodal and bimodal. Camels produced in China are bactrian camels, with a height of 2m and a weight of about 450kg. Their life span can reach 35-40 years. Camels were originally wild and domesticated more than 4000 years ago. Nowadays, wild camels are almost extinct in the world, and only a few of them are distributed in western Inner Mongolia, Gobi area in Xinjiang and sparsely populated places in northern Gansu, and are listed as national first-class protected animals.
The desert environment is harsh, the climate is dry, the temperature difference between day and night is large, and water plants are scarce. Camels have lived in the desert for a long time, and their body functions have a series of adaptability. It has two rows of long and dense eyelashes in its eyes, thick ear hair in its ear shell and windproof flaps in its nostrils, which can block the invasion of sandstorms. Its sole has a layer of meat pad about 0.5 cm thick, which can resist the high temperature of 70-80℃ in the desert or the cold in winter. Camels are covered with brown fluff about 10 cm long, which can be used to keep out the cold in winter and form a cooling gap between the fluff and the skin in summer to prevent high temperature radiation heat.
Camels have amazing endurance. When the temperature reaches 50℃ and the water loss reaches 30% of the body weight, they can not drink water for 20 days, and only when the temperature reaches 40℃ will they sweat a little. It can also carry a load of 200 kilograms and drive continuously for 4 days at a speed of 75 kilometers per day. Camel bees are used to store fat, and can hold 50 kilograms of fat at most, accounting for about 1/5 of the body weight. Camel's stomach and muscles can store a certain amount of water, and its first stomach can store nearly 100 kg of water at a time. Therefore, in the case that food and water can't be found at the moment, it can use the stored fat and water to maintain life. In addition, the camel's sense of smell is particularly sensitive, and it can detect and feel the water within 3 miles, which is very important in the vast desert.
Camels walk slowly, but they can carry many things.
Somatotype characteristics
Camel's head is very small, and its neck is thick and long, bending like a goose neck. Tall, with brown hair. The eyes are double eyelids, the nostrils can be opened and closed, the limbs are slender, the hooves are as big as disks, and the toes and soles have thick skin, which are all suitable for walking on the sand. The tail is slender and has tufts of hair at the end. There are 1 ~ 2 large humps on the back, in which fat is stored. The stomach is divided into three chambers (lack of flap stomach) and can ruminate. Mild temperament, often acting alone, eating coarse grass and shrubs. Life expectancy is about 30 years. There are two kinds of camels: dromedaries with/kloc-0 humps are mainly distributed in Arabia, India and North Africa; There are two humps, C.bac-trianus, which are about 3 meters long and more than 2 meters tall, and the distance between the two peaks is about 0.5 meters. The villi are well developed and have long hair under the neck. The upper lip is split, which is convenient for feeding. Camels are hungry and thirsty. They can drink enough water 1 time, but in hot and dry desert areas, they can move without water for several days. Because there are many extremely thin and tortuous pipes in their noses, the pipes are usually wet with liquid. When the body is short of water, the pipeline immediately stops secreting liquid, and a 1 layer hard shell is formed on the surface of the pipeline, which can be used to absorb exhaled water without losing it to the body. When inhaling, the water in the hard skin can be sent back to the body. Water is used repeatedly in the body, so it can resist thirst.
Historical origin
When it comes to deserts, people naturally think of camels. Because camel has the ability to survive in drought and harsh environment, and its special ability to travel long distances in the desert, people living in the Gobi desert are full of praise for it, and it is generally recognized as a "boat in the desert". Indeed, since ancient times, it has played an important role in spreading Chinese and western economy and culture. According to Hanshu, Loulanzhou in Lop Nur is "full of camels". He must be a bosom friend of Loulan people. I should say that he is also a close friend of all mankind.
Camels domesticated by people are livestock, which can help people to work. Wild camels found in Lop Nur depression more than a century ago have not been domesticated, and belong to self-supporting protozoa. Camels were called camels in ancient China because they were tall and good at carrying loads. Camel, carry the load. Today's cloud camel, the cover voice. ""Camel, a strange animal abroad, has two peaks, such as a saddle, three legs and a light brown color. If there is a load, you should bend your feet first. " ("Erya")
In 400 AD, Fa Xian, a monk in the Jin Dynasty, described it in "The Buddha said that Tianzhu traveled": "In the Shahe River, there are many evil spirits, and everyone dies. No one is perfect, and there is no bird in the wind or beast on the earth. If you look everywhere and want to cross the river, you don't know what you want, just mark it with private bones. " Xuanzang, a great monk in the Tang Dynasty, went to Tianzhu to learn Buddhist scriptures. When he passed through the desert, he also said, "Look around, people and birds are definitely lost." At night, the demon spirit lit a fire and rotted like a star; During the day, the wind is strong and the sand is scattered like rain. "I have been to the desert many times, and I don't think what they say is exaggerated. The environmental conditions in the desert are so sinister that only camels can adapt to such harsh environment. Real "natural selection, survival of the fittest. "
physiological characteristic
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Camel can adapt to harsh environment. It is not afraid of heat, thirst and hunger because it has its own physiological characteristics. According to expert research, firstly, camels generally don't sweat, so the water in the blood is well maintained and it is not easy to dehydrate, so the blood circulation is good; Secondly, camels have fine and soft fluff, which can not only keep warm, but also prevent heatstroke. Camels shed their hair every summer, but they still have a thick layer of hair, which can resist the sun's exposure like a blanket. No matter how high the temperature is, they will lose their hair.
two-humped camel
The temperature under the layer will not exceed 40℃. In addition, because the camel has a hump full of fat, it can help the camel regulate its body temperature, keep warm in winter and in summer. The temperature difference between day and night can be 6℃, that is, 34℃ at night and 40℃ during the day. Moreover, it has something to do with the low water consumption of camels themselves. Under normal circumstances, camels don't talk easily. Even in the hottest weather, it only breathes 16 times per minute, and only breathes 8 times when it is cool, so it won't consume too much water.
Camels have amazing endurance. When the temperature reaches 50℃ and the water loss reaches 30% of the body weight, they can still go without drinking water for 20 days. It can also carry a load of 200 kilograms and drive continuously for 4 days at a speed of 75 kilometers per day. Camel bees are used to store fat, and can hold 50 kilograms of fat at most, accounting for about 1/5 of the body weight. Camel's stomach and muscles can store a certain amount of water, and its first stomach can store nearly 100 kg of water at a time. Therefore, in the case that food and water can't be found at the moment, it can use the stored fat and water to maintain life. In addition, the camel's sense of smell is particularly sensitive, and it can detect and feel the water within 3 miles, which is very important in the vast desert.
Wild camels live in the extremely arid Gobi desert and desert, where there are few people and few animals and plants. Because there is no water, natural enemies (wolves, lynx, leopards, etc. ) can't survive. In order to avoid the invasion of natural enemies, wild camels with weak self-defense ability choose barren land to live and reproduce by virtue of their unique physiological functions. Newborn camels can stand up soon and walk in the desert with their parents. In order to get wonderful food, wild camels sometimes quietly come to the oasis in the desert, where water plants are fertile and food is abundant, but this will risk their lives, because it is also a place where wolves haunt.
Camels can not only ruminate, but also chew the food in their stomachs repeatedly, so that they will not starve to death when there is nothing to eat. It also has a pair of eyes that are not afraid of wind and sand. Because camels have double eyelids, they can walk leisurely in sandstorms even if they are violent. It also has the ability to predict strong winds. According to the "History of the North", "At the end of the year, there are hundreds of miles of quicksand in the northwest and hot air in summer, which is a disaster for travel. Where the wind comes from, only the old camel can predict, that is, it will gather angrily and cover its nose and mouth. The wind will subside. He must be exhausted. If you are not prepared, there will be danger. "
Also, it has a good digestive function and is not picky about food. The camel thorn, wormwood, false equisetum and feather grass on the Gobi desert are its favorites. You can drink 100 liter of water once, and then it doesn't matter if you don't drop water for a few days. Even if it encounters bitter salt water in the desert Gobi, it can drink it without care. Every time before going out, camel workers should feed it some salt to make it drink more water and store it in the body to increase its thirst tolerance.
In addition to the above specialties, camels also have a keen sense of smell. If it smells water in the distance, it will hold its head high, smell greedily, and then stride there without hesitation. According to Zhang Hua's "Natural History", "Dun feels brilliant, moving westward to quicksand, and there is no water for thousands of miles abroad. Sometimes there is a place where water flows and people can't know. If you cross it, you can't stop. If you step on the ground, dig where you step. " This shows that camels still have the ability to find groundwater. Li Shizhen's Compendium of Materia Medica also said that camels "can know the spring pulse, water pulse and wind condition, and people don't know what flow is, so camels step on it with their feet."
Characteristics and values
Camels have thick hair, and the desert is very cold in winter. Camel fur is extremely effective in keeping body temperature. Camel's thick hair can reflect sunlight. A shaved camel will sweat 50% more to avoid overheating. Fur also helps camels insulate themselves from heat. Their long legs also keep them away from the hot ground. Some people think that camels can swim when there is water. Camels are familiar with the desert climate. When there is a strong wind, it will kneel down and travelers can get ready in advance.
Camels in the desert
Camels are famous for their humps, but their humps are not used to store water. Unlike people's imagination, hump uses another method to achieve the same goal. The camel's hump is the accumulation of adipose tissue, and water is stored in the blood. When these adipose tissues are transformed, camels can not only gain energy, but also convert each 1 kg fat into 1 thousand 1 1 g water by reacting with oxygen. This ability allows camels to survive without drinking water for two weeks and eating for one month.
Camels can drink more than 100 liters of water in10 minutes. At the same time, they only urinate about one liter a day in summer, and their body temperature is about 40 degrees, so they will not open their mouths easily. These let camels stay in the desert for 8 days without drinking water and will not die of thirst. Camel's red blood cells are oval, which is different from other animals' round cells, so that red blood cells can still flow in dehydrated state. These cells are also more stable, and will not tear because of the change of permeability when drinking a lot of water. In addition, when mammals lose too much water, they need to extract water from their own blood to supplement it, but this will thicken the blood, which will lead to decreased circulation speed, metabolic dysfunction and heatstroke. Camels rely on water in their muscles to keep their balance.
Wild camel
Wild camels exist in many parts of the world in history, and only the western Mongolia and Ata Mountain in northwest China still exist in the wild. These areas are vast deserts, Gobi and other "barren land", which are not only dry and short of water, but also extremely hot in summer. The highest temperature is 55℃, and the temperature of gravel quicksand can reach 765,438+0 ~ 82℃. It is extremely cold in winter, and the temperature can drop below zero when a cold current strikes.
Wild camel
At 40℃, it is often windy, flying sand and stones. The harsh living environment makes wild camels practice extraordinary adaptability and have special physiological functions that many other animals do not have. They can not only endure hunger and thirst, but also endure heat, cold and sandstorm, so they are known as "boats in the desert".
Wild camels are tall and thin, with a body length of 2.2 ~ 3.5m, a tail length of 50 ~ 60cm, a shoulder height of 1.8 ~ 2m and a weight of 450 ~ 690kg. Small head, smelly glands on the back, secreting black smelly liquid. The snout is short, and the upper lip is split into two petals, like a rabbit's lip. There is a valve in the nostril that can be opened and closed at will, which can not only ensure smooth breathing, but also prevent sand from pouring into the nostril, and the water flowing out of the nose can also flow into the mouth along the nasal groove. The ear shell is small and round, with thick fine hair to stop the wind and sand, which can be folded tightly. There are two long and dense eyelashes outside the eyes and double eyelids. Double eyelids can be opened and closed independently, and clear vision can still be maintained in the diffuse wind and sand. It is said that it can also foresee the coming of storms. In the northern history, there is a saying: "Qiemo (a county in southern Xinjiang) has hundreds of miles of quicksand in the northwest, and there is hot air in summer, which is a travel disaster. Where the wind came, only the old camel foresaw it, that is, they gathered angrily and buried their noses and mouths in the sand. Whenever people think they are waiting, they cover their noses with blankets. It's windy. They must be exhausted. If they don't take preventive measures, they will be in danger. " Record.
The neck of a wild camel is long and curved, like a goose neck. Hair on the back can protect the skin from the scorching sun. The tail is short and has short fluff. There are two smaller meat humps on the back, the lower round tip is hard and conical, and the hairs on the peaks are short and sparse, without drooping hairs. In the past, it was thought that hump was an organ for storing water, but later studies showed that the structure of hump was mainly fat and connective tissue, which could accumulate up to 50 kilograms when it expanded, and gradually converted into heat energy needed by the body when it was hungry and deficient in nutrition. It also has an appropriately changing body temperature, which rises to 40℃ at night and drops to 34℃ at dawn to adapt to the large temperature difference in desert areas.
Wild camels have slender limbs, which are different from other ungulates. The third and fourth toes are particularly developed, with toenails at the toe end, big phalanges in the middle and big cracks between the two toes. The lower end of the 1 tubular bone connected with two metacarpals bifurcates into a "ya" shape, which is connected with the phalanx, and there is a spongy callus pad on the outside. The skin of the chest and elbow of the front knee and the back knee is thickened, forming seven wear-resistant, heat-insulating and warm keratin pads for kneeling and lying in the sand.
The light brown body of wild camel is capillary and soft, but short and light, with no other color type, which is very close to its surrounding living environment. When changing wool from May to June every year, the old wool does not fall off immediately, but forms a gap between the quilt and the skin for ventilation and cooling, so that the hot summer can be spent, and the old wool is not taken off until the new wool grows in autumn.
Wild camels have a keen sense of smell and are active during the day. They walk firmly and strut, but they are timid and alert. They are usually gentle, but when they are angry, they spit saliva and stomach contents. Although it can survive in the desert, it prefers to be close to water sources and lush grass, and it is often concentrated on the banks of rivers formed in the rainy season, where red willows, seabuckthorn and various weeds flourish. Only when the enemy threatens its survival does it hide in the vast sand sea. Its food is varied. Primitive grass, Stellera chamaejasme, reed, camel thorn and other poor and hungry desert plants that grow in the desert are all food for camels to satisfy their hunger. The stomach in the fourth room has a strong ability to store and digest food, so they can spit out the food in their stomach and chew it at rest. Wild camels are thirsty, too. They can live normally without drinking water for a long time, but their bodies are getting thinner and thinner, but after drinking water, they can fully recover within a few hours. The mechanism of thirst tolerance of wild camels has not been fully understood. It is generally believed that there are several reasons: First, under the condition of water, one can drink more than 10 kg at a time and store it in the water in the stomach; Second, there is a special protein in its plasma, which can maintain the moisture in the plasma; Third, its nasal mucosa area is large, which can prevent water loss; Fourth, the temperature difference between day and night is as high as 6℃, and the water consumption can be controlled by adjusting the temperature. In addition, its skin rarely sweats; Less urine; Dry feces, less water; Breathe less, never open your mouth to breathe and so on. Therefore, you can not drink water for several days in summer, or even for dozens of days in winter. Where salt springs and fresh water exist at the same time, wild camels prefer to drink the water from salt springs, which not only supplements the water, but also obtains the needed salt.
Wild camels generally live in groups, and most of them are scattered in families in summer. In autumn, they begin to form groups of about five, six or twenty, sometimes even reaching 100. When walking in the desert, adult camels walk in front and behind, and young camels are in the middle. They often eat and drink along a fixed route. This is the so-called "camel trail". Wild camels are good at running, quick in action, quick in reaction, alert in character and very sensitive in sense of smell. Some people think that it finds water in the desert by its sense of smell, or it may rely on its unique genetic memory.
June 5438-March is the estrus of wild camels every year. When males fight, they mainly stick their heads between each other's legs, trip each other up, and then bite them with their mouths. At this time, it can often be seen that wild camels who act alone are often losers in the courtship struggle, and there are also cases where estrus males run to the domestic camels to mate with female domestic camels. Females breed every two years, with a gestation period of 12 ~ 14 months, and give birth in March ~ April of the following year, with each fetus 1 offspring. Babies can stand 2 hours after birth and walk with their parents on the same day. They will be separated after 1 year. Sexually mature at 4 ~ 5 years old, with a life span of 35 ~ 40 years.
relevant information
Rickshaw boy
Author: Lao She
Time: 1936
Content abstract: The novel takes the life of Beijingers in China in the late 1920s as the background, and takes the bumpy and tragic life experience of rickshaw driver Xiangzi as the main plot. Xiangzi, the hero of the book, went to the desert to do business and bought a camel. The camel saved Xiangzi's life and took him out of the desert. Hence the name "Camel Xiangzi".