Why are vampire bats dangerous?


          Vampire bats are dangerous because they carry rabies and other diseases and infect their victims as they suck the blood which is their only food.



          Vampire bats (Desmodontidae) are found only in South and Central America. They have extremely sharp teeth and pierce the skin of their prey so gently that the victim does not awaken. Blood is drawn into the mouth by the almost tubular tongue and the vampire bat’s whole digestive system is specially adapted for his diet of blood.




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What are fossils?



          Fossils are the remains, moulds, traces or impressions of prehistoric animals and plants found in the ground. The word comes from the Latin fodere meaning to “to dig”, and originally meant any old, curious object dug out of the earth. But since about the middle of the 16th century, fossils have been regarded specifically as hard objects showing evidence of earlier forms of life, often many millions of years old.



       There are many kinds of fossils. Some are footprints which strange prehistoric animals left behind in mud long since turned to rock. Others are stones which were ones soft substances, but still preserve the outlines of extinct plants, or of seashells, or of the bodies of animals. Sometimes even the bones of creatures have survived.



      The study of fossils, which is called palaeontology, has enabled scientists to fill many vital gaps in the history of the world and its inhabitants. For example, fossils have shown that rocks in great mountain ranges like the Alps or the Rocky Mountains were once below the surface of the sea. They have indicated that the United States and Europe were once covered by tropical forests. Also, they provide evidence of the common ancestry of animals which today differ widely in appearance.



      The subject can be rewarding hobby for amateurs. Many important contributions to the world’s great collections have been made by people who looked for fossils in their spare time or even came across fossils by sheer accident.



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Where would you find a trap-door spider?


Trap-door spiders are to be found just under the surface of the earth. They belong to the class of spiders called mygalomorphae which includes the bird-eating spiders of the tropics. All these spiders tend to be rather large. They have four lungs instead of two, and their jaws work vertically instead of sideways.



     The trap-door spider has perfected the art of burrowing underground. Its jaws are provided with a special row of teeth with which to dig out its home. It lines its burrow with silk and makes a trap-door consisting of layers of silk and earth. The outside of this door is coated with moss or some other form of camouflage. The spider lies in weight behind its trap-door, darting out to seize its prey.



    Trap-door spiders are wide-spread throughout the hottest regions of the world, with comparatively few in the temperature zones. Specimens of up to four and a half inches have been found. It is estimated that some may live up to 20 years.



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Why do birds have different bills?


The shape of a bird’s bill or beak is closely related to the kind of food it eats and the way in which it collects or catches this food.



    A crow or jay has a strong all-purpose bill, capable of killing small mammals but fine enough at the tip to pick up small insects. Many songbirds have slender bills for picking up insects from leaves or out of cracks; others have wide flat ones for catching flies or strong thick one for cracking seeds and nuts.



    Birds which dig for worms usually have long bills with sensitive tips while many water birds have broad dredging bills. Divers and grebes have straight spear-like bills and the birds of prey have strong hooked bills for tearing flesh.



    Birds which catch insects on the wing (nightjars, swallows etc.) have tiny beaks but an enormous “gape” by comparison.



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When does a tadpole become a frog?


Frogs’ eggs become tadpoles within two weeks of being laid in the water, but tadpoles may take anything from two months to three years to change completely into frogs.



      The time taken seems to depend on the environment. Tadpoles will generally develop faster in warmer waters. Also the more advanced species of frog have simplified and shortened the process of transformation.



    Tadpoles, like fish, breathe through gills. They develop lungs during the change-over, gain legs and loose their tails. Their diet changes, too-tadpoles live on plants in the pond, but frogs live on very small insect.



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What are termites?


Termites are soft-bodied insects belonging to the family Isoptera. They are sometimes called “white ants” but they are like ants only in that both species live in social colonies. They live in the tropics and temperate. Countries and make various kinds of nests below the ground, but the most spectacular are large structures built above ground called “termitaria”. They are built from earth excavated below ground and cemented together by saliva. Some of these nests are 20 feet high and almost too hard to break open even with a pickaxe.



      The termite community is divided into four groups, but only two can breed. Each colony is founded by a “royal pair” and the queen’s life is devoted to laying eggs.



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Where are the largest animals found?


Blue whales are the largest living animals. They are cosmopolitan creatures and are found in most of the seas, from the polar caps to the equator. Normally those which inhabit the colder seas will migrate to warmer waters in winter.



    Their dimensions are almost beyond belief. Although figures can never be quite accurate, a blue whale can weigh more than 200 tons and many have been found measuring over 100 feet in length. The tongue alone, of a female whale found in Antarctica, weighted well over four tons.



      It has been estimated that in the 1930s there were nearly 40,000 blue whales in the world. But by the end of the 1960s there were fewer than 1,000 alive. This was because for the misdirected efforts of over-zealous hunters.



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What is the coccyx?


 



 



The coccyx is the lower end of the spinal column of man and consists of four nodules of bone, like tiny vertebrae, corresponding to the tail, which is found in lower animals. The bones are deeply buried in muscle tissue, but occasionally they jut backwards and are surrounded by a fold of skin, so as to form an actual tail.



    The name coccyx was given by the Greek physician Galen (c. A.D. 130-200) and free comes from the Greek word for “cuckoo”, as the bone rather resembles a cuckoo’s bill.



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Where did all the dodos go?


The dodo was rather a stupid bird. Indeed, it was so stupid that it was named dodo by the Portuguese when they discovered Mauritius-its home-in 1507. The Portuguese word doudo means stupid.



    Mauritius is an island, 720 square miles in area and lying 500 miles to the east of Madagascar in the Indian Ocean. Until the arrival of man, with his attendant creatures such as the cat and dog, the dodo had been able to live in peace. It had no enemies, which was fortunate because it was big and clumsy and was completely unsuited to fleeing from danger. Its short legs were almost incapable of supporting the weight of the fat, round bocy (about the size of a swan’s) and the ridiculously inadequate, stubby wings were of no use for flying.



    Within 180 years of its discovery by the Portuguese, the dodo was extinct. Over the intervening years several were brought to Europe alive, and one was to be seen in London in 1638. By 1680 the dodo had succumbed.



   With the help of drawings and by the collection of bones gathered in Mauritius has been made of the poor bird. It can be seen at the Natural History Museum in London.



    Mauritius is the only place in the world where the bird is known to have existed. A similar Island of Rodriguez, but this also has become extinct.



    The phrase “as dead as the dodo” is used to mean that something is very dead indeed.



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When did Pterodactyls live?



Pterodactyls (or pterosaurs) lived between 150 million and 70 million years ago. These extraordinary reptiles were able to fly. Some had a wing-span of over 25 feet, making them by far the largest flying animals known to man. Their skulls were often longer than four feet.



     Unlike the birds, their descendants, pterodactyls must have been unable to perch upright. They probably hung upside down like bats when sleeping or at rest.



     Since most remains of pterodactyls have been discovered among marine sediments, it seems likely that these flying dinosaurs found their food in the sea, like seagulls, by diving for fish.



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What do birds of prey eat?


Birds of prey are those that feed wholly or mainly on meat taken by hunting. They catch other birds, and small animals, for their food.



    There are two chief families, the hawks and the falcons. The hawks include eagles, such as the bald eagle (symbol of the United States) and the golden eagle. The falcons are smaller but share the same general characteristics-hooked beaks, keen vision and outstanding powers of flight. Owls, also. Feed on flesh.



    Besides being fast flyers, many birds of prey are expert at gliding and hovering. Their principal strategy of attack is the “stoop”, when from a great height they sight their prey, close their wings and swoop upon the victim. This manoeuvre calls for a combination of speed and last second breaking unique to this type of bird.



    In advanced countries birds of prey have suffered severely from the effects of poisonous agriculture sprays which have polluted their food sources. This has threatened their survival. But the danger has now been recognized, and in many areas their numbers are slowly recovering.



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Where does a bee keep its sting?


A bee keeps its sting at the end of its abdomen. At the tip of a bee’s abdomen is a shaft where is stinging thorn is to be found. It can sting several times, but once it leaves the thorn in its victim’s flesh it will not be able to sting again.



    It is not true to say that a bee will automatically die once it loses its thorn. Only female bees can sting. Male bees, or drones, lack this means of protecting themselves.



     There is a species of which even the female cannot sting. But these bees which live mainly in Africa and South America are not defenseless. If disturbed, they will fly at he intruder in great numbers, crawl into his eyes, ears and hair and smear him with a sticky substance, causing him to retreat in great discomfort.



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Why do most fish have scales?


Fish have scales as a protective coating for the skin. In fact, not all fish have them. But we usually think of a fish as a cold-blooded, aquatic animal that swims by means of fins, breathes by means of gills, and is covered with scales. Scales may be of four different kinds-placoid, ganoid, cycloid and ctenoid.



Placoid scales are long, spiny and tooth like, and are made of enamel and dentine. These are found on fishes which have a back-bone made of gristle, such as sharks and rays.



   Ganoid scales are rather like placoid scales but are mainly bony and covered with a kind of enamel called ganoin. These thick scales are found especially in garfish.



    Cycloid scales are thin, large round or oval scales arranged in an overlapping pattern. They are found in carps and similar fishes.



Ctenoid scales are similar to the cycloid ones, but have spines or comb like teeth along their free edges. These are found in the higher bony fishes, such as perches and sunfishes.



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What is a greenshank?


A greenshank is a little bird with a long beak and olive-green legs-a member of a group of birds known as sandpipers.



       The greenshank breeds in Scotland, Norway, Sweden and Finland. It builds its nest on the ground, being content usually to settle in a small hollow, lined with heather or dry grass. The eggs are pale buff or stone colour, blotched with purplish-grey and spotted with dark brown.



       Worms, insects and tiny fish provide the bird’s food. In winter the greenshank migrates, some-times as far south as Australia or South Africa.



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Where would you find live prehistoric fish?


Numerous fossil remains have been found of coelacanth fish which died over 70 million years ago. In fact the coelacanth is said to have first appeared some 350 million years ago.



      But to the amazement of experts the first living coelacanth was found in 1938 off the coast of South Africa. In 1952 a second one was caught on a line by a fisherman from the Comoro Islands, between Mozambique and Madagascar. Since then many more coelacanths have been taken around the Comoros.



      Modern coelacanths are bigger than most of the fossil forms. They average about five feet in length and can weigh more than 100 pounds.



      Usually they live among reefs, from which they will dart out on their prey. they are strong and powerful flesh eaters. The heart of a coelacanth is an S-shaped tube and is probably the most primitive of its kind in existence today.



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