Serengeti comes from the Maasai word siringet, meaning the place where the land runs on forever, and that is exactly the impression of the plains in northern Tanzania. Grassland stretches to the horizon, broken by granite outcrops called kopjes, flat-topped acacias and the green lines of rivers, and above it all the sky changes by the hour. The park covers nearly fifteen thousand square kilometres and joins Kenya's Maasai Mara to the north, forming the setting for the great migration, in which well over a million wildebeest and hundreds of thousands of zebra and gazelle follow the rains in an enormous circuit, with lions, cheetahs, hyenas and crocodiles waiting along the route.
The animals are here because of the soil and the seasons. Volcanic ash from the nearby Ngorongoro highlands has enriched the southern plains, which grow short, nutritious grass, and the herds gather there to give birth in the early months of the year, with the calving peaking around February. By the dry season they have moved north and west, and the crossing of the Mara river is the most dramatic scene of the year. Further south, the Olduvai Gorge, on the edge of the park, is where the Leakeys found the bones of early humans, and the area is often called a cradle of humankind.
I should be plain about the riding: motorcycles are not allowed in Tanzania's national parks, so this is a place for a safari vehicle, a ranger and a guide, and not a bike. The roads to the park gates, from Arusha via the Ngorongoro highlands or from Mwanza on Lake Victoria, are a mixture of tarmac and gravel, and in the rainy seasons, roughly March to May and November, black cotton soil turns to glue. Dust, corrugations and animals on the road are common hazards, and fuel in the remote north is scarce.
Park fees are high and must be paid in advance. Evenings on the plains smell of dust and woodsmoke, and the roaring of lions after dark is something that people remember all their lives.