When did People First Use Money?

            Money has always fascinated man ever since ancient times. Money has come to become the most important thing in the world. Aristotle observed that man is a social being who established certain norms and regulations for his social interaction. Man employed money as a mode of exchange to facilitate such social dealings for his economical aspect.

Indian Rupees
US Dollars

            In primitive societies, when people wanted to buy anything, they had to give something else in return for it. For example, if a potter wanted to buy rice form a farmer, he offered him earthenware in exchange offer rice. The farmer would accept them because he needed pots. This was called the barter system, which involved goods in exchange of goods.

            During those times goods served the purpose of money. But with the development of trade, the barter system could not meet the growing demands of convenient exchange system for buying and selling. People started using token or symbolic goods in exchange all over the world. American Indians used beads of shells, Fijians used whale’s teeth and North Americans used tobacco in their exchange system. The roman army men were provided salt for their services. But when was the coin first used as currency?

            The precise origin of money in the form of coins is not clearly known. According to the available sources, the earliest coins were minted in about 800 B.C. when Indians who lived in Asia used stamped pieces of metal as a medium of exchange. Some believe that the Chinese used coins even earlier coins were preferred because they were easy to carry and durable.

            The early coins were of irregular shape and were stamped with rough designs. The money value of coins depended on the value of the metal that the coins were made of coins were mostly made of gold, silver or copper because they were precious and durable metals.

            The use of paper currency was known to china as early as in the 9th century but it did not develop in Europe until the 17th century. The governments of different countries favored the use of paper currencies and coins to simplify the monetary dealings. It helped, because what mattered was the money value printed or stamped on them and not their real value. This is because the printed value on the currencies denoted their purchasing power as assured by the government. People accept a coin or currency in payment not because they value the coin itself but because they have confidence in the authority that issued it.

            As coins are heavy and bulky, larger payments are made in paper money issued by the proper legal authority.

Can one tree Produce the Fruit of a Different Tree?

            Seems very unlikely, isn't it? But it is possible!  It is a fact that many trees can produce the fruit of another kind of tree by a simple method called grafting. It is an artificial method or technique of vegetative reproduction in which a small branch or bud of any desired plant inserted into another rooted plant. This is called plant propagation. If a bud form a twig of pear tree is carefully inserted in a sit made in the bark of a quince bush, a pear twig will grow. The quince bush will bear both pears and quinces.

Grafting trees together

            In the same way, an almond tree can be made to produce both peaches and almonds. Although grafting is sometimes used to produce freak trees and bushes, this technique is of immense importance in agriculture. Lots of experiments in this field are still being carried on to produce better and newer varieties of fruits, flowers, corn, etc.

            The greatest advantage of grafting is that it can be used to improve the quality and quantity of a particular variety of plant or fruit. It is possible for gardener to be sure that his young trees or shrubs will bear the same quality and variety of fruit s the parent tree. A twig taken from a tree ad grafted into another tree will produce the same type of fruit borne by the tree from which it was taken.

            There are many methods for inserting the budded twigs or scions, as they are called, into the stock of another plant, but two rules must always be followed.

            First, only related species of trees or shrubs can graft. This implies that apples can be grafted into pear and quince trees, and peaches can be grafted into apricot, almond, plum or other stone fruit trees. It is impossible to graft apples on a peach tree. Secondly, the cambium layer a layer of actively dividing cells, which carries the vital sap of the scion, must touch the cambium layer of the stock into which it is grafted. Otherwise, the grafted twig cannot grow.

            There are different techniques of grafting. It can range from inserting a single bud under the bark to grafting long twigs across the wound of a tree in order to heal wide wound sin the bark. Tissue culture is popular these day in which cells form a plant are removed to propagate in another plant to obtain a hybrid product or the product of the original plant.

            The technique of grafting is now widely used in case of animals as well as human beings. There has been surgical operation in which a bone taken form the ribs have actually been grafted onto the nasal bone to form a new nose. Bu the best application is in cases of severe burns, where the healthy skin from one part of the body is grafted onto the burnt tissues to remove scars.

How do Plants Protect Themselves from Frost?

            There are over 350,000 kinds of plants in the world. All these continue to struggle to survive against storm, rain, sun and snow. These are some which die due to severe cold in winters, although before dying their seeds are dispersed on the ground, so that in autumn, they can produce new plants. However, there are some plants, which are able to protect themselves against winter.

            A coating of ice crystals is called frost. The plats are able to protect themselves against winter frost by a special method. They spared their leaves and flatten themselves against the ground. The warmth in the soil enters their leaves and the plant is protected. Some plants like myrtle and heather allow their upper parts to die but heir stem remains alive. Stems act as storage organs, both above and below the ground. They produce buds and thus preserve their species. Many plants hide themselves under the soil to escape the cold; these include tubers, bulbs and roots, which store their food according to their need. In summers, they push out green leaves and new buds.

            Some times, artificial methods are used to protect plants form frost, e.g., oil heater called smudge pots is use din the region where citrus fruits are grown. In some places, large fans are used to circulate the air, so that frost is not able to get deposited on the trees.

Which Insects Suck Through Straws?

            There are many insects, which have straws for sucking up the liquids. The insects, which have straws, are moths and butterflies. In the figure, an insect is sucking blood.

A Mosquito Sucking

            Insects have suck up liquids have mouths shaped like long tubes. Insects that suck include aphids, which have a sharp tube for piercing the stems of plants ad sucking out sap. Mosquitoes pierce our skin to suck up the blood. A housefly has a tube with a sponge-like organ at the end for sucking up liquid.

            In biological language, these straws are called a proboscis. Insects that drink nectar form flowers have the best straws. A butterfly normally keeps its long proboscis coiled up, only extending it when it intends to use it. The convolvulus hawk moth has a straw 14 centimeters long for reaching deep into certain kinds of flower. One type of South American moth has a proboscis that is 30 centimeters long.

How are the Stripes a Boon to the Zebras?

            Zebra looks like a horse that has worn a striped coat look different. It is a member of the horse family, but as compared to other members of this family it stands a part because of its striped coat. What is even more amazing is that each animal has its own special pattern of stripes.

Zebra

            There are three species of zebra that have survived over the ages. The most commonly found is Equus quagga-known either as the common zebra or as the plains zebra. It inhabits eastern and southern Africa-south of Ethiopia. The other species is Equus gravy, which is found in Somalia. It is the largest of all zebra species and has numerous thin stripes and very large ears.

            The third surviving zebra species is called the mountain zebra or equus zebra. It has numerous narrow stripes and is found in the mountains of Namibia (south-west Africa) and Angola. At one time, there existed a species called quagga, which had stripes only on its head, but this kind of zebra is now extinct.

            Since all the species have parallel black or brown stripe son a white background, it is not off the mark to assume that the stripes must in some way be helpful for these grazing animals. Although a number of theories have been put ot explain this phenomenon, none gives a very convincing explanation. According to one theory, the stripes create a dazzle pattern ad thus help the zebra to hide from its enemies by blending with the shadow-sunlight patterns of the grasslands where it lives. Since the lion is its main enemy, this physical characteristic helps it to camouflage. Other researches have suggested that the stripes are disruptive, and create confusion in singling out a individual zebra when they are bunched together due to the overlapping of their outlines. This helps in protecting them, as a lion (in theory!) finds it difficult to single out a potential victim.

            The gestation period of different zebras varies form 300 to 390 days. Usually one foal is born at a time, although twins are also a possibility.

            Zebras are grass grazing animals; some roam around in open grassy plains, whereas others live in rough mountains. They usually live in small groups and are great fighters. It is difficult to tame or train them. Zebra became almost extinct by 1880.

Which Lizard Squirts Blood from its Eyes?

            Sounds like a story fro horror fiction, but there are certain kinds of lizards that can actually squirt blood from their eyes! Lizards are mostly found in tropical countries. They are reptiles with a dry scaly skin and along tail. There are 3,000 kinds of lizards in the world.

The Horned Lizard

            But the lizard that squirts blood from its eyes is a lizard called the horned toad or horned lizard, and it is mostly found in Mexico and certain hot, dry part so north America. A number of theories have been put to explain this strange phenomenon. Although this lizard squirts blood very rarely, how does it manage to do so, and why does it do so?

            It has been observed that at times, the lizard is able to increase the blood pressure in its head, rupture the membranes of tiny blood vessels in its eyes and squirts blood up to a distance of several inches. According to the biologists, this action is a defense mechanism. When squirted into the eyes of an attacker, its blood acts as an irritant, and diverts the attention of the attacker.

            The Horned Lizard belongs to lguanidae family. There are about 14 species of this lizard. Dagger-like head spines or horns characterize it. Its typical features include a flattened oval body and pointed fringe, and scales along the sides of the body. The length of this small lizard ranges from 3 to 5 inches.

            These lizards usually live in deserts or semi-desert sandy areas. They feed on insects, mainly ants. These lizards can conceal themselves by wriggling sideways into the sand, until the entire body except the head is covered. Some people have tried to keep them as pets but they generally do not live long in captivity.

Do the Fishes Hear?

            The most surprising fact about fishes is that you cannot hear them but the can certainly hear you. Fishes are very well equipped with hearing organs. They do not have a pair of ears projecting outwards as in humans, but there are tiny holes on either side of their head, leading to the inner ear. Since there is no external ear to direct to the sound, these ears are probably not s effective as our own. But the fishes have other ways of picking up sounds of vibrations in the water.

A fish can hear various underwater sounds

            Along each side of the fish’s body is a line of littlie holes or pores, which can also pick up vibrations and changes in water pressure and pass on the message to the brain. This line of pores is called the lateral line, and can be seen quite easily. By using this lateral line, a fish can avoid all obstacles when it is extremely sensitive to pressure changes caused by the vibrations of another contains sensory objects. A fish’s lateral line contains sensory cells, which provide the fish with all the information in respect of activities going on around it.

            Teleost fishes such as the catfish that lives in rather muddy water have barbells-long sensitive feelers-on the sides of their mouths.

            Members of the carp family have tiny bones in the head, which are linked to the swim bladder. The swim bladder keeps the fish upright in water and also acts as a sounding board; which can pick up and magnify the feeble vibrations, and then pass them along the bones directly to the inner ear.

            Now you know how it is possible for the fish to pick up even the feeblest sounds around them.

How do we Study the Internal Structure of Plants?

            Have you ever glanced through a microscope in your school laboratory? If you look at a slide of plat stem through the microscope, you will be amazed to see the minutest details in cell. Botanists study the internal structure of plants mainly by examining their cross-sections under a microscope. These thin slices can tell us a lot about the structure of the cells that make up the plant and how they vary in different parts of the plant.

Internal Structure of Plants

            In 1665, a scientist named Robert Hooke looked at a piece of cork under microscope and saw that it was made up of many tiny compartments. He named them cells and this term has been in use eve since. The equipments needed for obtaining the sections include a sharp razor, a small fine brush and a number of watch glasses and microscopic slides.

            The sharp razor is used to cut off thin slices of plant stem as required. Cross-sections as well as the longitudinal pieces are obtained in the same manner. In case of fresh material, to obtain best results, the razor and the material must be kept moist with water. It should be cleaned with alcohol if the specimen is a preserved one.

            To prevent shrinkage, the sections are brushed with water or alcohol. For quick examination, the sections are placed on a slide with drop of glycerin. The thin ones that show the cells clearly can be obtained for permanent use.

            Staining is a process of adding dyes to observe the various tissues in different colors. The razor-cut sections are placed in alcohol and then dipped in a mixture of stains and alcohol.

            After some time, the sections are transferred to a series of watch glasses full of alcohol. This removes water and the excess stain. The alcohol is removed by dipping the sections in clove oil or benzene. The section is then placed on a clean glass slide with a drop of Canada balsam resinous glue). A thin glass is added as a cover ship and sealed by warming the balsam of harden it. The slide, properly labeled, can then be stored and examined whenever required.

            Details of time exposure for staining varies with the stain and materials used. The information can be collected form a textbook or worked out by practice. In laboratory analysis, many modern techniques are being adopted for in-depth studies on the subject.

Why do Cats Purr?

            When a cat wants to express satisfaction or pleasure, it purrs. Purring of a contented cat results in a low vibrating noise. It is a kind of low continuous rattling hum and has nothing to do with a cat’s real voice. A mother cat purrs when it wants to call her kittens for feeding. At birth, the kitten’s stages after birth, it is the purring of their mother that helps them to keep contact. Once the kittens start feeding themselves, the mother stops purring. So, we can conclude that purring began as a kind of homing device.

A Cat and Kitten

            Now the question arises- how does a cat produce the purr?

            The vibrations in a cat’s vocal cords cause the purring sound. When a cat takes air into its lungs, the air passes through the voice box that contains the vocal cords. If the cat then wants to express its satisfaction, it will allow the vocal cords to vibrate as the air passes in and out of the lungs while breathing. When it chooses not to purr, the air does not affect the vocal cords and thus does to produce any sound.

            Although there are many members of the cat family such as lion, tiger, leopard, jaguar, ocelot and lynx, whose throat structure is quite different from that of a cat and hence they cannot purr. However, they can make kinds of sounds.

Which Fish Keeps its Eggs in its Mouth?

            Eggs in the mouth? Sounds quite strange! But there is a fish known as the catfish, which is found in the Atlantic Ocean off the east coast of America. It is quite different from other fish as it keeps its eggs in its mouth. The interesting fact about it is that instead of the female, the male takes the responsibility of looking after the young ones. After the eggs are laid and fertilized, the male quickly puts them into his mouth. The young ones completely fill its mouth and prevent it for eating. The male fish carries them around for a month. During this period it is unable to take its food, and lives off the food reserves built up before the spawning. Moreover, his motherly role does not end even after the hatching of eggs. For two more weeks, the youngsters swim in to his mouth to hide when any danger threatens them. There are seven kinds of fishes, which are called catfish ad are found in eastern and central North America.

A Catfish has eggs in the mouth

            Some species, like the flathead catfish ad blue catfish, can weigh more than 45 kilograms. The catfishes live near the bottom of slow-moving rivers and lakes. They have four pairs of barbells around their mouth. These barrels look like the whiskers of a cat and hence they are called catfishes. The barbells are quite sensitive and help the catfish feel its way around and find its food.

            The male catfish plays the role of a mother immediately after the fertilization of eggs. The electric catfish is a variety which uses electrical discharges to stun and capture other fishes. Its electric organs lie just under the skin and cover its body and part of the tail. A large catfish may even produce a voltage of 350 volts.

            Another kind of catfish, the Wels catfish, grows to huge sizes in muddy-bottomed lakes in central Europe. Some specimens grow up to 9 feet in length and weigh 600 pounds; some others compete with Arapaima, which is claimed to be the largest freshwater fish in the world.

Why do Birds Sing?

            We all love to hear the bird’s songs. It gives us a very pleasant feeling, especially when we visit forests or travel to the countryside. Some birds produce very sweet sounds, while others produce harsh and unpleasant sounds. Do you know why birds sing?

A Bird Singing

            The songs ad calls are means of communication among the birds. They sing to attract mates in the mating season, to warn other birds of any impending danger form predators, and to establish their home territories or nesting area. The bird calls are usually distinctive and vary from species to species. This distinction helps the birds to identify the calls.

            In all species of singing birds, the male is usually the singer. It sings to attract female bird. The nightingale produces the best musical effects, which no other bird can match. The mockingbird has its own harsh call, but can imitate the songs of other birds. The crows make a very harsh cawing sound. You wouldn’t call a crow’s cawing musical, would you?

            Apart from singing, birds make other types of calls- calls for sending alarm signals, for food or calling their parents, calls made in an aggressive or hostile mood etc few birds, such as pelicans and cormorants are voiceless.

            The singing birds belong to the suborder, oscines. Their vocal cords are located n a special box, called the syrinx, located at the base of the windpipe where it divides into two bronchi. The syrinx has a bony structure ad forms a sound box within which membranes vibrate when the bird exhales. This produces varying notes in the bird’s sound. The structure of the syrinx varies from species to species, of which seven different types have been identified.

            Birdsong has a pinch of about 4300 Hertz, which is even higher of the calls of any single bird varies form the deep-pitched hoot of owls to the very high frequency chirping notes of small birds, which are barely audible to the human ear.

Which Insects Swim Upside Down?

            Did you know that some kinds of insects can swim on their backs? There are certain peculiar types of bugs’ called back swimmers greater water boatman that swim upside down. These back swimmers are also called boat bugs. Although they spend most of their lives in water, they are able to fly long distances. These insects are small, usually 3 to 17 millimeters 0.13 to 0.63 inch in length. Instead of wings, they use their legs to swim. They swim on their backs and make use of their hid legs to paddle through the water. These flat paddles are ideal for swimming, and re often made even more efficient by a fringe of hair, which runs down each side. This provides a broader surface to push the water. The insect uses its short front legs for holding its prey.

Backswimmers

            Backswimmers enclose a bubble of air between their wings and body. This air s used for breathing when they are underwater. This lets them stay underwater for as long as six hours. In winters, backswimmers bury themselves in the mud at the bottom of a pond or stream.

            They have sharp beaks, which they use for stabbing fish and other small water animals and suck out their juices as food. Backswimmers sometimes bite human beings.

            These creatures belong to Notonectidae family, which has in all about 200 species. They are generally found all over the world. They cause great harm to fishes and tadpoles. They deposit their eggs on the tissues of pond vegetation.

How do Animals and Plants Survive in Deserts?

            Due to the scarcity of water and extreme climatic conditions hot, dry, windy prevailing in the desert, it is very difficult for animals and plats to survive. They have to adapt themselves to the desert conditions so that they can live. Let us see what types of vegetation and animals are found there and how they survive.

Animals of Desert

            The vegetation of a desert mainly consists of thorny shrubs, cacti and palm especially dates trees. Cacti, prickly pear, saguaro, century plant etc., have adapted themselves to live in desert conditions. These plants have ways to store water in their fleshy stems. The leaves have squeezed themselves into tiny thorns to reduce the loss of water. The roots go deep into the ground and are widespread to collect every drop of water available in the soil. The stem stores the water and slowly gets thinner as the water gets used up. In some cacti, the thorns point towards the earth. The dewdrops deposited on the tips of these thorns fall to the earth and get absorbed by it. In this manner, a cactus plant manages to create moisture on the ground around it.

Plants of Desert

            Most desert animals sleep during the day to escape the high temperatures and come out at night in search of food. Some animals sleep during the hottest part of the year. There are very few animals found in deserts such as snails, pack rat, jerboa, etc. these have adapted themselves to the desert conditions. Animals such as the kangaroo rat and gerbil can survive with little or no water. Reptiles adjust their body temperatures to cope with heat ad cold. The Australia desert toad stores water in its body. Some species of lizards, ants, owls and snakes also live in desert sad adjust to desert conditions.

How do Some Animals Recognize their Offspring?

            It is said that only man has highly developed reasoning faculties and hence, can think, act and talk. Animals, too, have their own superior senses that excel man in certain activities. For example, dogs have deep smell and hearing sense that man does not have. Similarly, like human beings, animals have offspring and take care of them. But how do these animals recognize their young ones?

Animals use their sense to recognize their young ones

            For most animals where parental care is essential, it is important for the mother and her young ones to recognize each other, so that they do not lose contact. This is done through one or more of the five senses- smell, sound, sight, touch and taste. Most mammals recognize their offspring’s by smell. This is also observed among dogs, deer, sheep, horses and seals.

            It is interesting to note that in a flock of sheep, every mother can recognize her own young one by smell, and ignore others. When around one is born, its mother sniffs the newborn baby and the smell is immediately registered in its memory for life. Thereafter, the mother locates her baby b sniffing all the babies around until she finds her own lamb.

            Birds recognize their young ones b sound. Each parent bird has her own special mother call which the baby immediately recognizes on hatching, and the mother can also recognize the baby’s cry. An Austrian naturalist, Dr. Konard Lorenz, made a special study of geese. He conducted his study just before some geese eggs were about to hatch. He removed the mother goose and sat by he eggs himself. As the babies hatched, he gave the mother call. As a result, they be followed him every where believing him to be their mother, as they recognized only that sound, but since, he was too big for the young geese, they got confused when he stood up. However, they were quite happy to follow him when he crawled about on his hands and knees.

How do Plants Make and Take Their Food?

            It is a well-known fact that trees and plants are also living beings like humans. They need food, water and air for survival. It is interesting to know how they make their food.

Process of Photosynthesis taking place in the leaves of  plants

            Plants derive their food both from the earth and the air. If you minutely observe their roots, you will find that the ends of these roots are like fibers, also called root hairs. They absorb water and minerals and transport them upward to the leaves through the trunk and the branches. It is the leaves which make the food for the plant.

            Leaves have pores that are filled with air. They also have a green coloring matter called chlorophyll. This chlorophyll acts as a catalyst; it uses carbon dioxide from the air and the hydrogen from the water present in the leaves, to make carbohydrates sugars using sunlight as energy. This process is called photosynthesis. In this process, oxygen and water are by-products, which are releases by the leaves of plants.

            Sugar is further converted into starch. From these carbohydrates, the plants can build up complex substances as foods, which it needs for life and growth. These substances include proteins, juices, oils fats, etc. the water fro which the plants take hydrogen for photosynthesis contains dissolved minerals required for building various parts of the plant body. These are compounds of nitrogen, sulphur, phosphorus, sodium, calcium, magnesium, iron, etc.

            Food not immediately needed for growth is stored in the plant including its seeds, fruits, tubers or bulbs. On germinating, the new shoot uses the food that is accumulated in the seed.

How do Migratory Birds Find Their Way?

            Every spring, millions of birds migrate from their winter places of the temperate regions of the world, in order to breed. These regions have abundance of food where they can rear their hungry chicks.

Migratory Birds

            The biggest migrations are to the northern parts of North America, Europe and Asia. There is some migration to the southern hemisphere also. For example, the double-banded dotted flies form Australia to New Zealand to breed. The America golden plover undertakes a non-stop flight of 3325 kilometers form Alaska to Hawaii. In the northern hemisphere, wild geese fly north to their breeding grounds in spring and fly south in the autumn.

            Migration is mainly triggered by changes in the length of the day, which cause a change in the bird’s hormonal balance.

            Now the question is- how do the birds find their way while migrating from one place to another, and then manage to return to their original place?

            Young birds learn about migration from their parents. They make the first migration with the older birds, which have made the trip before. The bigger birds familiarize their young ones with the migration route. Landmarks such as mountains, lakes and coastlines, guide some birds. Other may use the sun and stars to navigate. When they sky is cloudy, they often get lost. Scientists still do not know full, how all migratory birds find their way.

            Birds are not the only animals that migrate. Many fish, mammals, flying insects, locusts, and eels also migrate.

How is the Bark of Tree Formed?

            Bark is the protective covering of tree branches, trunks and roots. The bark has three layers. The outer layer is called peridrem and is made of dead cells, such as seen in the cork tree. Periderm is usually thick, and protects the tree form whether, insects and diseases. The middle cortex layer is made of living, non-growing cells. The innermost cells, including the phloem transmit food made in the leaves down to the roots. The periderm of some trees has small openings called lenticels. Lenticels allow gases such as oxygen and carbon dioxide to enter and leave the plant.

Bark of a Tree

            As a tree grows, wood is formed and a layer of cells near the outer side begins to divide and produce crock cells. The walls of these cells soon get heavily thickened with a waterproof substance. These cells die and form the bark.

Layers of a cell inside a bark

            As the time passes, bark is constantly added to form the outside protective shell of the tree. As the diameter of the twig, branch or trunk increases, the waterproof barrier is maintained. The outer bark often splits and cracks or becomes flaky.

            The bark contains substances that repel insects and resist fire. Bark often has commercial uses. The actual cork comes from the bark of the Mediterranean cork oak. The drug quinine, a malaria medicine is obtained from the bark of cinchona trees and cinnamon comes from the bark of the cinnamon tree. Cough medicines and many other useful substances are also obtained from bark.

Does any Bear Wear Glasses?

            The kingdom of animals has always been source of fun, amusement and entertainment for man. We often discover amazing and interesting features and characteristics that are peculiar and unique to a particular type of animal alone. So when we say there exists a type of bear that wear spectacles, it sounds amazing, buy is it true?

A Spectacle Bear

            The truth is that the visual appearance of its face gives the spectator an impression that it is wearing a pair of glasses. In reality, lines of white-colored fur encircle its eyes and these circular lines around the eyes, look like spectacles from a distance.

            This spectacled bear is found in tropical South America. It is very small in size. An interesting pattern is made on its facial area when a creamy yellow snout with fur of the same color runs down from the nose and sometimes it makes a ring around the eyes. These rings are the so called glasses. These bears are also called the Andean bear. Some have only the bottom half of their glasses, whereas some have the eye-rings so thick that they encircle the face.

            Although there is only one species of spectacled bear known as Termarctos ornatus, there are different kinds of facial markings found within the same species. Though all bears can climb trees, the spectacled bear is an expert climbing through the branches to feed on leaves, fruits and nuts.

            The spectacled bear is the smallest among the bears. The adult is up to 64 cm 2 feet at the shoulders, 120 to 180 cm 4-6 feet in total length, with about 7 cm long 3 inch tail. The color of its shaggy coat varies from dark brown to black. It weighs less than 135 kilograms. Although, it may feed on small mammals, deer, guanacos and vicunas, it’s usually lives in cool mountain forests.
            Litters of one to three cubs have bee born in captivity after a gestation period of 8-8 ½ months.

Which Fish Spits at Insects?

            Fishes are the most numerous organisms among the vertebrates and they number more than 30, 000, which is more than all the other back boned animals put together. Each group has its own way of acquiring food. The archer fish spits pellets of water to shoots down insects sitting on overhanging plants. Its aim is quite accurate and it can easily dislodge a fly or beetle about four feet away so that it falls into the water. The archer-fish then dashes towards the insect and eats it.

Archer Fish Spits Insects

            It is interesting to know how this fish is able to direct the jet of water exactly at the intended target over four feet away. The roof of its mouth forms a long groove. If the fish suddenly closes its gill covers, water is forced from the gill chamber into the mouth. At the same time, the tongue is raised, so the groove becomes a long tube from which the water squirts in a jet. Even more remarkable, it has adapted to the refractive index-caused  perspective distortion air and water have different indices of refraction; this means that an insect is not where it appears to be, when see form underwater! If you have seen a spoon bending in glass tumbler of water, you know why it is such a feat for the archerfish to shoot insects down form underwater, you to shoot insects down from underwater. They improve their chances of a kill by swimming as directly under the prey as possible, so that the distortion is at a minimum.

            The archerfish is a fresh water fish, and belongs to the family toxobidae. It is found in India and Indonesia. It got its name from the manner in which it captures its prey. Archerfish can also live in seawater. Toxotese jaculator is the most commonly known fish of this family. It can grow up to 18 cm in length. These fishes generally feed on insects.

Can a Scorpion Kill a Man?

            Everyone is scared of scorpions because their sting can be deadly, but they do not go out of their way to brother humans. Scorpions are small insect-like creatures that belong to the class arachnidan. They live in the tropical areas of the world. They hide in dark places, under logs or stones, and wait for their prey.

A Scorpion

            Their fossil history dates back 400 million years, and it is believed that hey must have been among the earliest of land-living arthropods. Today, about 600 species of scorpions have been studied.

            Scorpions are normally sky creatures, and lead a solitary life. In homes, they find safe hiding places in shoes, beds and even under the carpets, and if threatened or disturbed, they sting repeatedly. However, the severity of the sting varies from species to species. Though its sting is very painful, normally it is not fatal.

            However, some tropical species like the Egyptian scorpion, Lemurs, can be very dangerous and may even cause death. The poison acts by paralyzing the nerves of the heart and the chest muscles. In the United States and Mexico, more people die form scorpion stings than from snakebites.

            These deadly scorpions are usually black or yellow in color, ranging form 1.3 to 17.5 cm in length.

            The body of a scorpion can be divided into two major parts. The first part is the cephalothoraxes, which comprises the head and the chest. The hind part is a long abdomen, which tapers to form tail. The tail has a sting at the tip. Scorpions have a pair of claws and four pairs of legs. The claws are like pincers and used to capture their prey. Scorpions use the sting, which is located at the tip of the tail, to stun or kill their prey.

            Scorpions are nocturnal animals i.e., active mainly at night. They feed largely on insects, spiders and other small animals. The female scorpions bear their young alive. The newly born scorpion babies stay with the mother for several days, clinging to her body with their tiny pincers.

            The sting is a curved organ at the end of its tail and two glands at the base give out a position that flows form two process. Most people fear the scorpion because of its sting. However, most scorpions do not sting human beings unless troubled, and prefer to retreat rather than fight.

Why can’t Animals Talk like Us?

            Wouldn't it be nice if your pet dog could speak and share its thoughts with you? Many stories for children are about animals that can talk like human beings, but this is only a thought of the authors. Amongst all living beings, man is the only creature on earth that can communicate with the help of words of speech; this is because of the highly developed human brain. Since the brain in animals is not so well-developed they are unable to utter words or a language to express their feelings. That is why they cannot talk like us.

Animals express their feelings by gestures

            It is well-established fact that animals also feel happy, experience, sorrow, fear, love, affection, hostility, hunger, thirst or protective needs, etc., just as humans do. Because they are incapable of expressing their feelings in words, they express or communicate with the help of certain gestures and sounds, which may or may not be familiar or understood by us. You might have seen when a cat goes near a group of birds; all the birds start chirping very loudly in a peculiar way. They actually express their fear that the cat may kill them. Similarly, a dog expresses its anger by barking and its feelings of happiness by wagging its tail. A monkey demonstrates its anger by making peculiar sounds.

How do Some Creatures Make a Shell on their Body?

            You must have heard the sound of conch (shank) being blown during worship in the temples. You must have also seen big and small conches on the seashores and on the riverbanks. Some conches are so small that they can be seeing only with the help of a magnifying lens. While there are others that are as big as measuring up to 120 cm.

Snail

            Do you know what these conches are and how they are formed? They are the body shells of aquatic creatures. These creatures are called mollusks. The scientists have so far studied approximately 60,000 species of the mollusks. As the mollusk grows; the outer shell also grows and becomes harder. They are made up of calcium carbonate lime. The mollusk collects lime form seawater and deposits it in its outer shell. When the mollusk dies, the shell floats and comes to the surface of water.

            The shell of the mollusk has three main layers. The outer layer of the shell is made up of smooth material like the oyster and contains absolutely no lime. The middle layer is made up of calcium carbonate. The inner layer comprises man thin layers, which are made up of oyster-like material and calcium carbonate. Conches come in many colors. Some of them have pattern of stains and stripes on them. These stains, colors and stripes have their origin in some colorful materials present in the glands of the mollusk, and these colors, stripes and stains enhance the beauty of the conches.

            The conches protect the mollusk living inside. When the mollusks finally die, the shells become very useful to us in many ways. In early times, people used mollusk shells (cowries) as coins.

            Small conches are even used in necklaces, and as decoration pieces in homes. Mother-of-pearl buttons are made from small shells. Aquatic animals with shells have existed for billions of years. After their death, these shells are deposited on the seabed, which form limestone rocks.

Can Animals Reason?

            It is generally believed that animals do not have reasoning power but it is not true. They do have the power of reasoning but it is much less as compared to human beings. The degree of reasoning varies from animal to animals and even within species.

Monkeys are the most Intelligent of all Animals

            Some experiments have led to the conclusion that monkeys and apes have better power of reasoning than other animals. An experiment was conducted to test the reasoning power of monkey. In these experiments two wooden boxes were placed in a room and a bunch of bananas was hung at a height beyond the reach of the monkeys. When a monkey was left alone in the room it liked at the bunch of bananas for some time and then liked at the boxes. It put one box on top of the other and then climbed on them. Thus proved that the monkeys could think and find a way to reach the bananas. Again a monkeys is an animal that can also discriminate colors. It can be trained and taught to learn many tricks.

            Scientists believe that dogs, cats and some other animals can also reason up to some extent. For instance per dogs can be trained to learn many things. You might have seen a beat show in which the bear acts according to the commands of its master it is obvious that it uses its memory in it’s for food. Whenever they see any food they fly down to eat it. The lizard approaches its prey very cautiously and carefully. This indicates that the lizard uses reasoning to capture its prey.

            If you look at birds nests, you have to concede that a cretin amount of reasoning has hone into making them. These nests have special arrangements for regulating heat and light e.g. nests of weaver birds. Nests are fabricated for laying eggs and protecting the young ones.  

Which Birds Cannot Fly?

There are several species of birds that cannot fly because they stopped using their wings for flying thousands of years ago. Perhaps neither the environment round them nor their living conditions wanted them to fly. Generally birds fly to protect themselves from enemies and in search of food. These flightless birds either lived in places where there were no enemies to prey on them or they were so big that they could rely on their legs to run away from trouble. As a result their wings fell into disuse and gradually they became flightless.

Kiwi

            Do you known which are the birds which cannot fly?

            First of all we have the penguins. They turned their wings into paddles or flippers. As a result they cannot fly but they are excellent swimmers. Theses birds mainly live in the southern hemispheres mostly at the edge of Antarctica.  

            The kiwis in New Zealand took to living by night, finding food by smell and almost ceased flying. Gradually the bird become flightless. It almost stopped using its eyes also and become weak eyed as well. These birds now have small wings which are hidden by hair like feathers covering their bodies.

            The most ferocious flightless bird is the cassowary that lives in Indonesian jungles and is also found in Northern Australia and New Guinea. It is not scared of either man or beast and is quick to attack with the talons on its long legs.

            The biggest flightless bird of the world is the African Ostrich mostly found in Savannah. Growing to a height of 2.5 eaters it can run at a speed of 60 kilometers per hour covering a distance of 4.5 metres in one stride.

            Rhea is another flightless bird that lives in the grasslands of South America. The Australian emus is also a flightless bird next to the ostrich in size.

            One interesting thing that has been observed by scientists is that most flightless birds live in areas where there are few natural enemies.

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