You have read "Flying Without Wings," in which the author describes different animals, other than birds, that can fly. Write an essay analyzing how the author develops and refines the central idea of the text. Use evidence from the text to support your response.

As I write, there is a curious little brown-eyed creature darting around about me in the trees. Now, spread out like a parachute, it springs in the air, coming down lightly, only to dart to some other elevation, thence to repeat its antics again and again.

2
As you must by this time suspect, this creature is a flying squirrel—one of the familiar examples of a large number of animals that can move through the air without wings. If we closely examine this pretty little creature, we find that between the fore and hind legs there is an expansion of the skin, which, when the legs are spread out, offers a decided resistance to the air and buoys the animal up exactly as though it carried a parachute. When it is in midair, notice how careful it is to hold its feet and hands out as far as possible, to catch all the air it can. If we look closely, we shall find attached to each of the hands delicate bones, which, when the squirrel is in flight, act as booms for the curious sail in front.

3
But it is in the woods, in their native haunts, that the beautiful animals make their most wonderful leaps. From the tops of the tallest trees they launch themselves fearlessly into the air, coming down with a graceful swoop from a hundred feet or more; then, by a movement of the head, change their course to an upward one, they rise ten or twelve feet, and finally alight upon the tree of their choice. They immediately scramble to the top to soar away into the air, thus traveling through the woods from tree to tree much faster than you can follow them. How alike they are to birds, building nests for their young, and moving through the air with almost equal freedom!

4
One of the most curious of this family is the sugar squirrel—a beautiful creature, with large, curling ears of a delicate ash color above and white beneath. Like many squirrels, it is a nocturnal or night animal, lying concealed in its nest in some hollow tree until the sun disappears, when it comes out, and spends the night in wonderful leaps from tree to tree, in search of food and perhaps amusement. When descending from a great height, it seems as though they must inevitably dash headlong against the ground, so precipitate is their flight, but this never happens. That they are able to change the direction of their flight while in midair seems a very natural and reasonable supposition, though only on one occasion has the accomplishment of this feat been observed.

5
In the forests of the islands constituting the Indian Archipelago is found a curious flying animal that resembles the lemur and the bat. The natives call it the colugo, and also the “flying fox.” Like bats, these animals sleep in the daytime, hanging from the limbs and branches of trees, head downward, but as evening comes on, they sail forth, often doing great harm to the fruit on the neighboring plantations. In some parts of Java they are so numerous that it is found necessary to protect the fruit trees with huge nets. The extent of their flight through the air is something astonishing. They sometimes drop to the ground and hop along with a shuffling kind of leap, but if they are alarmed, they spring to the nearest tree and in a moment reach its top by a series of bounds. Out upon the branches they dart, and with a rush are off into space. Sailing through the air like some great bird, down they go obliquely, swift as an arrow, a hundred and fifty feet or more, rising again in a graceful curve and alighting safely on a distant tree. In these great leaps they carry their young, which cling to them, or sometimes follow them in their headlong flight, uttering hoarse and piercing cries. The colugos live almost exclusively on fruit, preferring plantains and the young and tender leaves of the cocoa-palm. These flying lemurs are perfectly harmless. They have lovely dark eyes and very intelligent and knowing faces.

6
So, the next time you are out in the woods, look closely at the animal flying overhead. You may be surprised at what you see.