The end of summer on the Serengeti plains heralds the mass migration of millions of wildebeest to fresh grazing in the north. Opportunist predators follow in their wake, targeting the stragglers on the outskirts. The thirst-driven animals reach the Grumeti River in the winter where they meet the cunning and stealth of some of Africa’s largest crocodiles. These engorge themselves on the inexperienced young and the weak that venture too close or linger for too long beside the precious water. Remarkably the magnitude of the wildebeest herd is unaffected by the onslaught of greedy predators and they pass en masse to greener pastures leaving behind a chain of satisfied eco-links.