Category Plants & Animals

                Viruses are micro organisms which cause various diseases in all types of living bodies, so much so that even bacteria are affected by viruses. There is a helpful virus called bacteriophage which eats bacteria and can not be seen by necked eye. One can only see them with the help of an electron or ultra microscope. Strangely enough, viruses are considered both as living and non-living objects. They grow and multiply in living cells and therefore are treated as living organisms. Since they do not grow outside living cells. They are classified as non-living objects also. Consequently, they are treated on the border line of living and non-living matter.

                  Viruses were first discovered by Mayer in 1888. He found them on tobacco leaves. There are many kinds of viruses. They are of varying shapes and sizes. Some are long as rods, some are hexagonal. The smallest viruses are of the size of a millionth part of an inch. They are found in the cells of plants, animals and human beings. They are born in these cells, multiply there and spread diseases.

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              Kangaroos are marsupials (animals with pouches) that live in Australia and New Guinea. Most of them live on grassy plains and feed on plants. They move about in troops, springing along on their big, powerful hind legs and large feet. Their long tails help them to balance.

              There are five species of kangaroos. Red and grey ones are the largest. A red kangaroo may be taller and heavier than a man. Grey kangaroos can bounce along at 40 kilometres per hour if chased. Wallaroos are smaller kind of kangaroo.

              A full grown kangaroo stands about six feet tall. Its front legs are short while the hind legs are very long. The powerful hind legs enable the kangaroo to take long jumps of 3 to 5 metres at a time. If a hunter or hunting dog chases a kangaroo, it runs very fast making long jumps. It can cover a distance of 7 to 9 metres just in one jump. When a kangaroo is cornered by hunting dogs, it can seize a dog with its forelegs and kill it with one swing of its hind legs.

             The female kangaroo has a pouch in its belly in between the hind legs in which it keeps its young ones till they grow up. When a baby kangaroo is born, it is a tiny, pink, naked mass of about 2.5 cm in length and about 1 gm in weight. Not only the infant kangaroo, but even young kangaroos need the protection of their mothers. A kangaroo lives on the mother’s milk until it leaves the pouch at the age of 6 to 8 months. A kangaroo lives for about 6 to 8 years. Finding the young ones in danger, the mother kangaroo lifts them with its mouth and places them inside its pouch.

           The kangaroo is a mild animal like the sheep and goats. Like the hare, it is unable to see an object just in front of it. But its power of smelling and hearing is quite strong.

           Have you ever seen a cat sitting in the dark? Though its body is not visible, yet its yellow eyes shine in the darkness. The eyes of tiger, leopard, lion etc. also shine in the darkness or night just like the eyes of a cat. Besides these, there are many other animals whose eyes shine in the dark.

           The eyes of these animals have a thin layer of a special crystalline substance which reflects the light falling on it. This reflected light is the cause of the shine. In the night, even the smallest amount of light falling on this crystalline surface gets reflected and thus we see the shining eyes. Animals with such eyes that can see things clearly in darkness are called nocturnal animals.

           Studies made on cats have shown that behind the retina of eyes, there is a crystalline layer called the ‘luminous tapetum’, which reflects light. Due to this layer the cat can see clearly in dim light and its eyes shine in the dark when the light is directed on them. Many animals do not have this crystalline layer; hence their eyes do not shine in the dark.

          It has been observed that the colour of the shine is different in different animals. It depends upon the number of blood vessels present in their eyes. If the number of blood vessels is large, the colour of the shine is red and if the number of blood vessels is small the colour of the shine is white or pale yellow.

Dog is regarded as a faithful animal. But when it goes mad it becomes very dangerous. If a mad dog bites someone, it leads to his death if not treated properly.

              A dog goes mad when it suffers from a disease called ‘rabies’. This disease is caused by a virus which is carried by air or by some wild animals and enters the dog’s body through a wound in its skin. The virus is bullet shaped having a diameter of about 70 milli-microns and a length of about 210 milli-microns. It moves from the saliva to the infected wounds and through sensory nerves to the central nervous system, multiplies there and then destroys brain cells. The dog becomes lazy, suffers from fever and loses all interest in food. In about 4-6 weeks, when these viruses affect the dog’s brain, the dog gets excited. It growls and barks and saliva froths from the mouth. During this period, the dog can bite anybody. This is the stage when the dog is said to be mad. After these symptoms appear, it is likely to die within 3 to 5 days. Some infected dogs do not go mad but show signs of paralysis, called ‘dumb rabies’.

             When a mad dog bites a man, the virus present in its saliva enters man’s body through the wound. Initially the victim experiences mental weakness and uneasiness which is followed by fever. He suffers from lack of sleep and feels frightened. The muscles in his throat get slackened and he faces difficulties in swallowing food or liquid. He is afraid of water. That is why this condition is also called ‘hydrophobia’ which means ‘fear of water’. These signs appear in the victim within one to three months after dog’s bite. In cases of dog-bite, the affected portions should be immediately cleaned and anti-rabies injections should be given to the victim within three days of the bite, the number of injections varying from 3 to 14 depending on the location and number of bites.

             The virus of rabies also attacks foxes, jackals, monkeys, cats and rats because they have the least contact with us. 

            Ants are insects that belong to the order Hymenoptera. More than two thousand species of ants have been studied by scientists. Ants are found in most parts of the world. Most ants are smaller than an inch.

            Ants are social animals and have their own kingdoms. This means that they live together in large colonies or groups. Some colonies may contain millions of ants. Most colonies make nests in the ground or in dead trees.

            There are three kinds of ants in each colony – queens, laying eggs; males who do not work; and a corps of female workers. An ant colony contains too many cells or chambers for different purposes. The queen lives in one, laying eggs. Next door is the hatching room, from which the grubs as they turn into pupae are carried into another room to develop. The other rooms are used for special purposes such as storing food etc. An ant colony may contain several queens each with its own suite of rooms. Worker ants collect food, feed the young ants and build the nest. Some species of ants also have female soldier ants. They protect the nest. 

Continue reading “Do Ants also have their kingdoms?”