It is the annual wildebeest migration, often billed as one of the seven natural wonders of the world, that has planted Maasai Mara so firmly in the popular imagination. The numbers are far down from their peaks of over a million wildebeest in the 1960s and 70s, but still an average of nearly half a million animals swell the Mara’s sedentary population ever year.
With a lemming-like instinct, the herds gather in their hundreds of thousands in May and June on the withering plains of the Serengeti to begin the long journey northwards, following the scent of moisture and green grass in the Mara. They arrive in July and August, streaming over the Sand River and into the Sekenani side of the reserve, gradually munching their way westwards towards the escarpment in a milling mass, and turning south again, back to the Serengeti, in October and November. Never the most graceful of animals, wildebeest seem to play up to their appearance with unpredictable behaviour; bucking like wild horses, springing like jack-in-the-boxes, or suddenly sprinting off through the herd for no apparent reason.
The Mara River is their biggest obstacle. Heavy rains falling up on the Mau Range where the river rises can produce a brown flood that claims thousands of animals as they try to cross. Like huge sheep (they are, in fact, most closely related to goats), the brainless masses swarm desperately to the banks and plunge in. Many are fatally injured on rocks and fallen branches; others are skewered by flailing legs and horns. With every surge, more bodies bob to the surface and float downstream. Heaps of bloated carcasses line the banks; injured and dying animals struggle in the mud, while vultures and marabou storks squat in glazed, post-prandial stupor.
The migration’s full, cacophonous impact is awesomely melodramatic – both on the plains and at the deadly river crossings. This superabundance of meat accounts for the Mara’s big lion population. Through it all, spotted hyenas scamper and loiter like psychopathic sheepdogs: a quarter of a million wildebeest calves are born in January and February before the migration, of which two out of three perish in the Mara without returning to the Serengeti.