The Great Wildebeest Migration
Every year, around 1.5 million wildebeest; 350,000 Thomson’s gazelle; 200,000 zebra; and thousands of eland and other ungulates (hoofed animals) participate in what has been called ‘the greatest show on Earth’, The Great Wildebeest Migration.
The three groups of migrant grazers have different grass-eating habits: as one group eats the top of the tallest grass, the next group will eat away some of the medium-height grass, until finally it is almost completely eaten, and the herds move on. This means each group sticks to their own kind with only a small overlap in their distributions. The grasses of the plains have the highest protein content in the whole of the Serengeti, as well as being high in calcium.
It is unclear how the wildebeest know which way to go, but it is generally believed that their journey is dictated primarily by their response to the weather; they follow the rains and the growth of new grass. While there is no scientific proof of it, some experts believe that the animals react to lightning and thunderstorms in the distance. It has even been suggested that wildebeest can locate rain more than 50km away.
The Great Migration in January, February and March
Around January each year, the migration will be finishing a southwards trek, moving along the eastern edge of the Serengeti and into the Ngorongoro Conservation Area. Here the plains are rich in nutritious grass, providing the herds with the best conditions for raising their newborn calves.
Although there is no real beginning or end to this migratory circuit – other than birth and death – it seems reasonable to call the wildebeests’ birthing season the start of the migration. Around late-January or February, the herds occupy the short-grass plains that spread over the lower northern slopes of the Ngorongoro Crater highlands and around Olduvai Gorge. Some 400,000 calves are born here within a period of two to three weeks – some 8,000 new calves every day.
The abundance of vulnerable young calves means the surrounding predators also spring into action, hunting with ease due to the sheer numbers of wildebeest.
The Great Migration in April and May
After bearing their young in February and March, around April the wildebeest herds begin to drift north-west towards the fresher grass of the central Serengeti, drawing with them thousands of zebra and smaller groups of antelope. By May, columns of wildebeest stretch for several kilometres as the animals start to congregate by the Moru Kopjes. Mating season begins towards the end of May and male wildebeest battle head-to-head. Throughout ‘the rut’, the journey continues at leisure, with the wildebeest, zebra and gazelle grazing as they go along.
Gradually, the movement gathers momentum and the wildebeest start to mass in the Serengeti’s Western Corridor. At this time of year, (true to its name) will have relocated to follow the migration and provide access to watch the wildebeest cross the Grumeti River. The herds form in huge numbers along the pools and channels of the river, which they have to cross in order to continue on their journey. This may not be as spectacular as the famous Mara crossings, but there are still enough wildebeest to provide the Grumeti crocs with a veritable feast. It is worth noting that May is low season at Ubuntu; safaris at this time offer great value, since there are relatively low numbers of tourists in the Serengeti yet the wildlife viewings remain excellent.
The Great Migration in June and July
During June, the dry season starts, with large concentrations of wildebeest in the Western Serengeti and on the southern banks of the Grumeti River. Each migrating animal must face the challenge of crossing the crocodile-infested river – the first of many daunting and tense river encounters.
As June moves into July, the hundreds of thousands of wildebeest and zebra continue to head north along the western edge of the park towards an even riskier barrier: the Mara River in the north of the Serengeti. These river crossings are arguably one of the most exciting wildlife events on Earth; they usually start at the onset of high season in July, but timing all depends on nature.
The Great Migration in August, September and October
By August, the herds have faced the challenge of crossing the Mara River and are spread throughout the Masai Mara’s northern region, with many remaining in the northern Serengeti. In years when the river is in full flow, the panic and confusion at the crossings – combined with waiting predators and surging currents – can cause massive loss of life. But, even in years of relatively gently flowing water, the crocs take their toll – not to mention the lions and other large predators that patrol the banks, ready to ambush any wildebeest that make it to the other side. There is no single crossing: at some spots, there are just a few individuals, while others see a mass of animals moving without break for hours.
By September to October, the main chaos has ended and the migrating columns have gradually moved eastwards. However, they wildebeest will face the heavy waters of the Mara River once more as they prepare to cross once again for their return journey southwards.
The Great Migration in November and December
After the East African short rains in late October and early November, the wildebeest move down from Kenya and into the eastern limits of the Serengeti past Namiri Plains, an area known for outstanding cheetah sightings. By December, they are spread throughout the eastern and southern reaches.
In the early months of the new year, the grasses in the deep south of the Serengeti are lush with rain. This draws the herds – not only of wildebeest, but also hundreds of thousands of zebra and other plains animals. The cycle continues as the calving season starts once again.