What's it like to witness "the Great Migration"?

Observing the animals on the Serengeti plains may bring to mind the decadence of a midnight buffet, the kind you find in Las Vegas or on cruise ships. A bonanza of feasting goes on: The greatest concentration of grazing animals on the planet, including wildebeests, zebras, gazelles and antelope, are there, munching on grass. As they feed, lions, hyenas and other predators feed on them, while vultures swoop in to clear the table, so to speak.

But the thought of all-you-can-eat buffets is likely your last thought of human civilization when you witness the Great Migration. Every year, the grazing animals cross hundreds of miles, from the Serengeti in Tanzania to the Masai Mara National Reserve in Kenya and back again, to eat fresh grass, watered by the rains. Once these animals start moving, you have the sense of something primal.

In short: You're seeing something that's been seen by very few humans before.

The animals' movement starts quickly and without any discernible warning. How do they know it's time to move, you may wonder. While everything looks normal and serene on these grasslands to you, wildebeests can sense a thunderstorm from 30 miles away. They follow the scent to get the best grass.

For people who like to count sheep before going to bed, the migrating animals represent an insomniac's dream — it would take almost 35 sleepless days and nights to count one migrating animal per second. The line of animals would stretch back for miles, giving you plenty of time to add up those 3 million animals, the majority of which are wildebeests. Nothing, not massive lines for Black Friday sales or queues for a subway after a downtown sporting event, could prepare you for that many animals moving together at once. The line of animals may stretch back as far as 25 miles.

But your ability to count the running wildebeests and leaping gazelles may be hampered by the beating hooves hitting the ground in the race for fresh grass or the cacophony of grunts and snorts that fill the hot air.

While the grazing animals leave many of their natural predators behind in the Serengeti, the trip, which may cover as many as 1,000 miles, isn't without its dangers. When the wildebeests go leaping and splashing through rivers, you may spot a hungry crocodile emerge from below to snatch them. But the wildebeests will gain in numbers again in the early spring, during foaling season. Many in the group will give birth all at once, and their labor is quick. Look away for just a second and you may miss the foal making its entrance into the world. The tiny wildebeest will get its footing, and then the race for grass is on again.

After all the adventure, the grazing beasts wind up where they started, in the Serengeti, and nature's food chain buffet begins again.