PLANET EARTH Great Plains

On temperate plains around the world summer is a time for growth and reproduction. Now the grass produces it's flowers. New colors also come to the plains. The northern flowering is mirrored by the grasslands of the southern hemisphere. And nowhere is more impressive than on the velt of South Africa.



Not all temperate plains are so rich and colorful in the summer. This is midsummer on the Tibetan Plateau the highest great plain in the world. Despite the conditions, grass survives, and in sufficient quantities to support the highest of all grazing herds those of the wild yak. Even in summer life is hard temperatures rarely rise above freezing, and the air is thin.



It's also exceptionally dry for one very big reason the Himalayas. The great mountain range acts as a barrier preventing clouds moving in from the south and this casts a giant rain shadow that leaves Tibet high and dry. Grass clings to life even as desiccating winds remove what little moisture remains in the soil. So long as grass can survive, so can grazers.



Wild ass（驴）. The males are fighting to win territories those that hold the best, are more likely to attract a herd of females. It's a frisky business. That counts as a victory but he can't assume the females will actually turn up. Female asses are mysterious creatures. They come and go as they please and much of their behavior seems unfathomable（深不可测的） to an outsider.