La migration des Gnous Christine et Michel Denis-Huot . Promenades Photographiques de Vendôme.

"One of the last great migrations of mammals takes place in East Africa—the migration of the wildebeests.

One day, as if instructed by a hidden signal, the animal herds on the Serenghetti plains start heading north in a great cloud of dust, driven by an irresistible force. They slowly make their way, heads down, in a chorus of moos. Some lines of animals can extend 40 kilometers without interruption. Sometimes the animals begin to run, as if temporarily mad, before stopping for no apparent reason. In the immense herds the confused cries of the animals can create “rumors” that ripple outward. Their numbers provide protection. This roundtrip exodus that spans nearly 1,500 kilometers is a dangerous trial for these herbivores and, conversely, a veritable buffet for their predators. One of the most challenging obstacles on their path is the Mara River in Kenya. The wildebeests cross at specific points, often near steep cliffs. Hundreds of animals die at each crossing. Although these points originally posed little challenge, they have been worn down to cliffs by years of passage. But nothing stops the animals in their migration, not even the strong river currents.

The first wildesbeests hesitate to cross. They move through the bushes on the water's edge, then climb back up to the plains. Those who turn around upset all the others. This waltz of hesitation can last for hours, even entire days. When the first animals decide to cross the river, the herd pushes them from behind into the water. The young, separated from their mothers and struggling through the swirling waters, cry out in terror. Others turn back, adding to the confusion.

Once the first animals are in the water, the herds behind follow in a frenzy, mindlessly, seemingly oblivious to their surroundings. This mass of animals thrown into the unknown is an extraordinary sight.

Every year the herd leaves hundreds of carcasses in the river, but they don't last for long in these waters teeming with crocodiles, vultures and catfish. Some years, the feast of carnage is too plentiful and the river remains full of bodies.

The arrival of the wildebeests at Masaï-Mara has a profound effect on the plant life there. By trampling and grazing its long grass, they create short grass pastures, much appreciated by other herbivores. These strange wildebeests condition the lives of the other animals sharing the ecosystem. Their movements respond to weather patterns. They cross and recross the river. Then, in October or earlier they head out in the opposite direction. Why do they return even though the rains should allow them to remain where they are? One response lies perhaps in the quality of the grass.

The wildebeest migrate for reasons of nourishent. Their story is at least as old as ours, an ongoing search for green pastures and water, dependent entirely on the weather. No two migrations are alike."

Christine et Michel Denis-Huot