tailieunhanh - BIOMES OF THE EARTH - GRASSLANDS Part 7

Con voi châu Phi (Loxodonta Africana) sống trên thảo nguyên trong đàn, mỗi đàn dẫn của phụ nữ lâu đời nhất, được gọi là "matriarch." Bê này sẽ tiếp tục bú mẹ của nó cho ba hoặc bốn năm (hút bằng miệng của nó, chứ không phải thân cây của nó) trước khi tiến tới một chế độ ăn uống dành cho người lớn của cỏ và lá trong mùa mưa và các cành cây, chi nhánh, và vỏ cây trong mùa khô. | 156 GRASSLANDS The African elephant Loxodonta africana lives on the savanna in herds each herd led by the oldest female called the matriarch. This calf will continue suckling from its mother for three or four years sucking with its mouth not its trunk before advancing to an adult diet of grass and leaves during the rainy season and twigs branches and tree bark during the dry season. Courtesy of Fogstock world s most spectacular annual migration takes place. The principal players are the wildebeest. Throughout the rainy season the wildebeest live in herds that are scattered across the plain. There are few rivers in the Serengeti and as the rainy season draws to a close the eastern part of the plain begins to dry out and the pasture deteriorates. Wildebeest herds in the northeast start moving southward joining with herds from the southeast moving westward out of the Ngorongoro area. Herds of Burchell s zebras inhabit the same areas as the wildebeest both species feeding on red grass Themeda triandra see Savanna grasses on pages 95-98 . The zebras also join the wildebeest herds and move with them. By the start of the dry season usually in early June the combined herds comprise about million wildebeest 300 000 Thomson s gazelles and 200 000 zebras as well as other species of antelope and some buffalo. The herd is accompanied of course by lions leopards cheetahs hyenas hunting dogs and jackals the predators and scavengers that hope to live well off this vast source of meat. GRASSLAND ECOLOGY 157 The herds spend the dry season in the moister west of the plain and as the dry season nears its end in about November they continue along their circular route back to the northern and eastern plains. The complete circuit is about 500 miles 800 km long and many animals die along the way. Soon after the migration begins the wildebeest mating season commences. Each bull attempts to establish a territory it defends against rivals and in which it can contain a herd of females. .