Social Science Questions & Answers

The ‘powder’ on the wings of moths and butterflies is really a layer of any, colored scales, which overlap each other almost, like the tiles on a roof. If you touch the wings with finger the “powder” is rubbed off, leaving the wing more or less transparent and colorless. The scales are generally like the shape of a hand tapered …

Birds preen themselves to clean and waterproof their feathers, to maintain their general health and to keep them lying smooth and neat. This preening or grooming starts as the nestling’s feathers are breaking out of their sheaths. The young bird spends a great deal of time combing the feathers with its bill and freeing them from bits of sheath and …

Not all birds migrate, but a lot of them do, two of the best known British migrating birds being the swallow and the house martin, which fly south in the autumn to spend the winter in parts of Africa. The reason they do this is because of the need for food, of which there is a great shortage in northern …

Birds which peck grain and other seeds also peck grit to help them to digest these hard foods. Because birds have no teeth, the work of chewing, which would require muscles and strong jaw bones, is done by the gizzard. This makes it possible for the skull to be delicate in structure and therefore light in weight. Grit is taken …

There are two kinds of beavers: the American and the European. The European beaver, found in Norway, Poland, Germany and France, lives in burrows. But the American beaver builds a dam across a stream or lake to construct his home or lodge. The lodges are made of huge logs of trees. The American beaver constructs solid dams and lodges because …

Bats use high-pitched sounds to find their way about. They are nocturnal animals. That is they move about by night. So they have developed their hearing to such an extent that they can find their way by a method known as echo-location. The blind-flying abilities of bats were first studied by Lazzaro Spallanzani (1729-1799). He surgically removed the eyeballs from …

The dodo, a large clumsy bird, which could not fly used to live on the island of Mauritius near Africa. But European settlers changed the dodo’s habitat and took away its supply of food. By 1681, there were no living dodos. It was extinct. Many other kinds of animals and birds have become extinct in recent years. There are many …

Christopher Columbus was an Italian from Genoa living in Portugal. Although in the fifteenth century most people still believed that the world was flat, others including Columbus, had come to believe it was round. If this was so, he argued, a ship could sail around the globe and return to its original starting point. Thus the shortest route to the …

The night vision of owls is 100 times as keen as that of human beings, because their eyes are especially adapted for seeing in the dark. But most are almost color-blind and the pictures they receive are slightly blurred. This is because their eyes contain more rod-shaped receptor cells than cone-shaped ones. Operating in bright light, cone cells sharpen details …

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 …