Wildebeests on the Move
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In
the rainy season, life returns to the African plain. |
The Serengeti Plain was dry and lifeless on this November day. Only small clouds of dust moved, as the wind swirled them around into dust devils and sent them skimming over the brown stubble of dead grass. Soon the rainy season would begin, and this enormous nature reserve would be overrun with some of Africa’s most fascinating animals. But how long would we have to wait for rain?
We were prepared for waiting. We had packed our large truck with food, water, and clothing to last the two of us more than a week. When we study animals in the wild, this Land Rover is our home away from home.
Through a layer of dust on our windshield, we scanned the plain with binoculars. Thunderheads of moisture were building in the sky. Finally, plunk! The first drop of water hit the windshield and scattered the dust. Plunk, plunk, plunk-plunk-plunk! Raindrops pummeled the ground, sending thousands of little puffs of dust into the air.
Soon the rain poured down, thunder rumbled, and bolts of lightning struck the plain. We know the danger of lightning on the plain. We sat in the truck, hugging our knees, careful not to touch any metal. Outside, puddles formed over the ground, grew larger, and connected with one another. As suddenly as the storm began, it ended, and the life-giving water sank into the soil. This downpour was just the first of many rains that would fall in this season.
Four days later we knelt on the bare, damp plain. Tiny points of green were sprouting among the remains of last year’s dead grass. The return of life was starting.
We made many safaris such as this one over the next few months. By January the bare brown plain had vanished. It was hidden under a lush carpet of brilliant green grass and herbs. Next came the herbivores—the creatures that eat the plants. One night we went to sleep in our truck all alone. When we woke up, more than fifty thousand wildebeests, or gnus, were grunting, clopping, and swishing their tails as they grazed past us. It was Wildebeest Time. The migrating herds had arrived!
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Hyenas (above) and lions
(below) |
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The Serengeti migration has been going on for thousands of years. This annual journey takes many animals onto the short-grass Serengeti Plain in the wet season and back into the woodlands during the dry season.
Why do they move back and forth? Most scientists believe that the herbivores move onto the plain in the rainy season because the grass there is more nutritious. But the grass grows only when it rains. When the rains end, the animals must move back into the woodlands, where the coarser grass is less nutritious and probably less tasty. The woodlands do not dry out as much as the plain does, so animals can find something to eat there.
How do wildebeests “know” that their favorite grass is starting to grow and that it is time to migrate to the plains? As the birth season approaches, mothers might sense their need for better food as they notice far-off storms. Scientists have seen wildebeests move toward storms a hundred miles away.
In addition to wildebeests, many other animals journey onto the Serengeti Plain. As we drove past, dainty gazelles snorted in alarm and stamped their little hooves. Zebras brayed and ran away for a short distance. They looked over their shoulders at us. Topis and hartebeests, elands and buffalo—movement and noise were everywhere.
We saw a newborn wildebeest. Every January and February, 250,000 such calves are born here. What a good time and place! The plain has both grass to eat and pools of rainwater loaded with minerals dissolved from the soil. The newborn’s mother drank. She needed the minerals for her milk.
The little calf struggled to its feet in just four minutes. It had its first drink of milk as we watched. Twenty minutes later the calf wobbled along next to its mother as she moved deeper into the herd, out of sight.
Suddenly the herd began to stampede. Zebras barked in alarm, gazelles leaped over one another in panic, and we felt the vibrations of thousands of pounding hooves running away. The predators were here.
African
wild dogs were chasing the wildebeests. We climbed on top
of the truck and watched through binoculars until they disappeared
from sight.
For a few beautiful months each year, the Serengeti Plain has everything: grass, herbivores, and carnivores (meat eaters). The wildebeests come to eat the grass, and the carnivores come to eat the wildebeests.
Wildebeest Time came and went. The rains slackened, then ceased. Near the end of May, the grass stopped growing, and the herbivores ran out of food. Long thin lines of wildebeests and zebras grazed past our truck, migrating westward toward the hazy, faraway treeline on the horizon, toward Lake Victoria. When the herbivores departed, the meat eaters followed.
By July the plain was silent and still except for the dust devils skimming over the brown, dead stubble. The plain waited for the rains, and for Wildebeest Time.
