The great migration, Tanzania

Join Michael Woods in Tanzania as he walks you through one of the greatest animal migrations in the world

7 mins

Fine grey volcanic dust billowed upwards in seething clouds which drifted slowly like dry ice poured onto the stage for theatrical effect. Just occasionally a breeze came swirling over the plain to whisk the dust away and reveal string after string of trudging wildebeest, plodding in unbroken chains, maybe ten abreast, past my vehicle.

For a few seconds the lowing antelope, grey as the dust itself, were visible and then the wind fell away and the ash particles rolled up once more to hide the migrating mass.

Tanzania’s Serengeti Plains are a vast sea of grass. Trees won’t grow here for the soil is too thin and so the grass holds sway, broken only now and then by fists of bedrock punched upwards to form fertile islands in this rolling ocean. It was from one of these rocky strongholds known as kopjes that I witnessed what I had come to see – probably the greatest migration in the world, the famous movement of wildebeest in the Serengeti-Mara system.

Britain, a small island with an equable climate, does not have large migrations of mammals although we are familiar with migratory birds which appear like magic in the spring having flown thousands of miles, often from far south of the equator. But there are major mammal migrations elsewhere – reindeer in Lapland (Finnmark) and their equivalent, caribou in Canada, zebra in and around Savuti in Botswana, various species in the Kalahari Desert and, of course, the apocryphal lemmings. Most move in response to climate changes which ultimately control their food and thus their survival.

But while many of these migrations are simply a direct movement from one place to another as the year passes and the seasons change, the wildebeest migration is much more complex than that. These animals are rarely in one place for very long and so it has no proper beginning and no end, but is a continuous process.

In late January and early February the females produce their calves on the short grass plains in the south of the Serengeti. This is a well synchronised operation so that there are literally thousands of young calves around at the same time. The so-called short grass plains are specifically chosen calving grounds for that very reason. Animals that flock or herd rarely hide. Instead, by choosing an open area, they can spot approaching predators and use the combined protection of thousands of pairs of eyes to spot danger.

Wildebeest calves are charming creatures. Chestnut brown and with large eyes and long, dark lashes they are programmed to react to stimuli rather than to think. They have to respond instantly if they are to survive and the second the herd takes to its heels, they must run too. There is no time to look for mum, the calf just follows the first moving object.

Sometimes there are glitches...

Obviously this strategy works or wildebeest would have become extinct years ago but sometimes there are glitches. Youngsters become separated and wander off by themselves. I once came across two calves in an open woodland strung out along a dried up watercourse. They were in cool shade and well hidden here but the nearest wildebeest herd was now many miles away. Disorientated they began to follow my vehicle until I was able to shake them off. It would have been a surprise to me if they had survived the night. Some passing hyena would surely have put an end to them.

For the local lions and hyenas, cheetahs, jackals and vultures, wildebeest calving is time to party. Food is abundant and they become round as barrels and plump as bolsters. Lions, when we found them, mostly lay buried deep in the cool shade of reeds close to water and were even less active than usual. The males of coalitions slumped together, manes tangled with thorn twigs, while lionesses could barely summon the energy to lift an irritated paw and bat away playful cubs which pestered them more than the flies.

Hyenas were massed in the largest clans I had ever seen – I counted one of 22 members – as clearly this was the place to be. Even they lay bloated with plenty, often half in and half out of cooling water and glutinous mud.

While the living may be easier, don’t get the wrong impression; the prey does not stand around waiting to be gobbled up and the predators do not have it all their own way. Young wildebeest can run from three minutes of birth and keep up with the herd within two days. The adults are no slouches. They have remarkable stamina, not only to migrate long distances, but also to flee from predators for several kilometres without flagging.

The predators do become very fit though and I watched a cheetah hunt where, remarkably, the animal had sufficient energy and enough choice to hunt a second time within a few minutes of failing the first.

It was a moment of high excitement as the cat, which had previously looked like a gatepost planted in the Serengeti as it haughtily surveyed the scene, abruptly flattened itself into the grass. It had all the colour and thickness of a doormat so that it almost disappeared. The tension was palpable as strings of wildebeest trundled past his unseen form – cow, calf, cow, calf – and then the cat launched himself, jet-propelled, dust exploding from every footfall, a streak of golden buff, black spots blurring.

The chosen calf swung through the column, which was now running, and galloped in a tight circle back into line. The cheetah gave up and flopped into the grass and, amazingly, the wildebeest continued to file by. A few hundred later, the cat had caught his breath and this time there was no error. He nailed lunch in a matter of moments, suffocating it under the noses of the passing column.

Tied to their territories

But, while wildebeest are nomadic, their predators are tied to territories and so, luckily for the antelope, it is impossible for every Serengeti lion and hyena to converge on the short grass plains and the residents can eat only a certain number of calves. They make full use of this time of plenty, for their numbers are controlled by the leaner months during the rest of the year. Thousands of calves survive to join the herd for their long convoluted trek northwards.

At first, quite literally, they chase the rains, apparently smelling moisture on the breeze and moving to feed on the fresh green grass which springs from the desiccated ground.

They do this throughout the months of March, April and May, slowly and almost imperceptibly drifting northwards from the area between the Moru Kopjes and the Gol Mountains until they find themselves north of Seronera for the rut in June. This is another spectacular time as thousands of bulls try to collect and hold as many cows as possible over a three week period. The noise is incredible as the males call, fight and chase in a frenzy of mating. Then, almost abruptly, it is over.

Now the herd splits into two and travels rapidly north to make the dramatic and much-filmed river crossings in August. Once again there is safety in numbers. If the animals crossed individually, the crocodiles could grab them one at a time. As it is, the wildebeest take the river by storm, pausing tentatively on the bank and then pouring over in huge groups.

The crocodiles get their fill no doubt, some wildebeest get killed in the crush but the majority reach the far bank to catch the short rains in the Mara.

Here the Kenyan predators cash in but luckily they cannot store meat to see them through the rest of the year. By late October their bush supermarket is fresh out of wildebeest as the herds make the hazardous crossing once more and head south, reaching the short grass plains by late December in time for the calving.

Not every wildebeest which dies falls foul to predators. Just occasionally one will keel over for some inexplicable reason and simply become a dead body out on the plains. I came across one of these antelope freshly dead from causes unknown, and set the clock going and sat back to see what would happen.

Within 20 minutes the first white-backed vultures arrived, floating in on broad wings, legs outstretched to come to a standstill several metres from the carcass. Vultures are nothing if not suspicious. But, after a few tentative approaches, one began to peck cautiously at the antelope’s upper lip. There was no reaction and the bird got bolder. The minute it stepped nearer, all of its fellows, who had been hanging back, fell on the wildebeest in a hissing, writhing mass, each one tearing at the animal wherever it could.

But these vultures can only cope with the soft parts, lacking the strength to tear through skin. No matter, the circling tower of stacked scavengers had attracted the attention of three passing hyenas who came loping in to take their share, driving the vultures off with a noise like an old tarpaulin being shaken in the wind. It would not be long before only bones would remain. Wildebeest, it seems, are everybody’s breakfast. No wonder they keep on the move!

When to go: As wildebeest tend to follow rain, timing a visit to coincide with reasonable accessibility can be difficult. The Serengeti during the rains is sometimes impassable – it may be better to catch the last of the calving, to time your visit for the rut (June) or, if you are very lucky, one of the river crossings (August). Seek advice from a specialist tour operator.

Health and safety: It is recommended that you have jabs against yellow fever, typhoid, tetanus and hepatitis A and it is essential that you take anti-malarial tablets. Wear a hat and sun cream and take insect repellent. 

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