When our winter season comes, the sun has moved southward, and shines directly down on the land to the south of the equator. The heat center, or Zone of Doldrums, then goes south of the equator. At this time the hot trade wind from the Sahara again blows over the northern grasslands and dries them up, but the doldrum belt is making down pours of rain on the grasslands south of the equator. The climate of the African grass lands seems to act like a kind of see-saw: while heavy rains are falling south of the equator, everything north of it dries up; up and down, up and down, the seasons shift. The hot tropic grassland regiOns have but two seasons: rainy, when the sun is over head (summer); dry, when the sun is on the other side of the equator (winter).
747. The dry season.—When the grass lands are receiving the hot sun and the desert wind, there are months when no rain falls; most of the streams dry up; the ground becomes so hard and dry that it cracks open. The grass is turned into natural hay without being cut. Unless burned, it stands there, making good forage for the animals. At this season water is often hard to find. Travelers sometimes see hundreds of animals standing around a mud hole where they have drunk up the last of a pond of water. (Fig. 557.) If a stretch of grass has been burned, grass eating animals stand in the burned-over space when they are not feeding. There they are safe from lions that would sneak up through the tall grass, and spring upon them.
748. The rainy season.—In the time of our summer, which is the Sudan summer also, the trade wind from the dry desert stops blowing across the Sudan. Light breezes may blow in any direction. The Zone of Calms has now come, bringing a sultrygdamp ness to the air. The mornings are bright and clear, but the heat fair ly bites. Then big white clouds rise, and in the after noon heavy showers of rain fall, accompanied by much lightning and thunder.
Water runs in the dry gul lies. Swamps, ponds, and lakes form in the lowlands.
Grass grows so fast that it almost seems to jump. Leaf less trees put out new leaves, as our trees do in spring. Birds build nests and rear their young.
This season of rain is shorter near the desert than it is near the forest. Sometimes, near the desert, it lasts only a few weeks in the whole year, leaving many long months of burning sunshine; sometimes only a little rain falls and famine comes. People pray for a long rainy season. On the other hand, in the equatorial forest some tribes pray for a short rainy season.
749. the rainy season the Nile overflows and large swamps form along the upper Nile and about Lake Chad. Since this lake has no outlet, it uses every rainy season and floods large areas of flat land; then in the dry season it dries up again.
750. Grassland animals.—The broad stretch of the Sudan is the home of grass eating animals. Here live the antelope, of which there are many kinds, and the giraffe, the rhinoceros, and the ostrich. Here also are the meat-eating animals that prey upon the grass-eating animals. This is the home of the lion and the leopard; of the hyena and the jackal. The elephant, a grass-eater, lives in the more bushy parts of the grasslands. It is not long since elephants were found all the way from the Sudan to the Cape of Good Hope, and lions from the Cape to the Mediterranean.
751. People and Suda nese are large, strong, black people. They have different ways of making their living in different parts of the region. On the northern or desert side, where the dry season is long and the rainy season is short, and where the rains are uncertain, the people are nomads, with flocks of camels, sheep, and cows. They raise camels to sell to the cara van traders. The light and irregular rains sometimes cause dreadful famines, which make the hungry people raid and plunder their more prosperous neighbors. These tent dwellers do not enjoy the rainy season. When it comes they sometimes run away from it and move out into the edge of the desert, where they camp by some stream which is fed by the rains to the south of their camps.
South of the nomad belt, where the rain fall is greater, the people can grow crops of grain. Here the Sudanese are farmers. They live in villages of houses that have mud walls and grass roofs. Close to each village is the hand-cultivated garden. It contains cassava (Sec. 369) and durra, which are the great breadstuffs, and beans, peanuts, pumpkins, and other vegetables. Instead of bread, the native of the grasslands and often, too, the native of the Kongo eats corn-meal mush, and boiled leaves of the cassava. Meat is a lux ury which is often used as seasoning for the mush; some natives eat no meat at all. Some natives of central Sudan keep flocks and herds and raise a little cotton for their own use. In this farming country there are many towns. The largest, Kano, on one of the higher sections of British Nigeria, had a hundred thousand people even before white men built the railroad to it.