The Great Land Migration and the Mara River

Every year over 2,000,000 animals travel almost 3,000 kilometers between the Masai Mara Natural Reserve in Kenya and the Serengeti National Park in Tanzania. This is known as the great migration and is one of the biggest in number of animals. The Mara River is directly in the path of the migration and is one of the most dramatic crossings.

The wildebeest, zebra, and gazelle follow the rains and fresh grass in a roughly circular route. From December to March they are on the short-grass plains of the southern Serengeti. From May onwards, as the grass dries out, they move north and west. By July they reach the Mara River — one of the only perennial rivers in the region — and must cross it to reach the green pastures of the Maasai Mara in Kenya.

The Mara River crossings are legendary for their drama: thousands of wildebeest plunging into crocodile-infested waters, swept by strong currents. Hundreds sometimes drown. Crocodiles, hippos, and predators on the banks profit from the crossing. But the vast majority make it across and continue north. By October, the rains return to the Serengeti and the herds begin their southward return, crossing the Mara again.

This migration — one of the greatest wildlife spectacles on Earth — depends on the Mara River's perennial flow. SELVA's work to protect and understand the lower Mara River Basin is thus not only about human water security, but about sustaining one of the world's most iconic ecosystems.