PLANET EARTH Great Plains

This is how grass can grow given unlimited sunshine and water but on most tropical plains across our planet the wet season is followed by a dry one. On the African savannas, grazers are marching in search of grass and water. Without rain, these plains can become dust bowls. Grass can now loose its hold.



Elephants are in immediate danger. They must drink almost daily. Driven on by thirst, they march hundreds of miles across the parched plains. Relying on memory, the matriarchs（女家长） lead their families to those special water holes that saved them in previous years. This one still has water but they must share what remains with desperately thirsty animals of all kinds.



These are tense times. The elephants dominate the water hole but as night falls the balance of power will shift. Thirsty herds continue to arrive throughout the night. It's a cooler time to travel. In the darkness the tables turn. The elephant's night vision is little better than our own but lions have much more sensitive eyes. The cats are hungry and the elephants seem to sense it.



Lions don't usually hunt elephants, but desperate times require desperate measures. This herd contains calves easier targets. But how to reach them? The adults encircle their young. It's an impenetrable wall of grey. A few exhausted stragglers are still arriving. One of them is alone. But it's too big for the lions to tackle（擒拿）. This one looks a little smaller. A solitary（独居的） lion stands no chance but the whole pride is here.