The herds of God

The great wildebeest migrations in Masai Mara

Javier Yanes


(Publicado en 'Msafiri', revista de Kenya Airways, nš34, febrero-abril de 2001)

Kenya, the land where safari was born, is the place to experience one of the world's most stunning nature spectacles: the great migrations of hundreds of thousands of wildebeest and zebra that each year ford the Mara river searching for fresh food.

Africa frequently seems not any more what it used to be. Human encroachment of traditional wildlife haunts, together with development associated to modern times, have erased the ancient image of wild animals roaming free through unspoiled and savage wilderness. Today, many national parks and reserves in Africa are fenced, both to prevent poaching and to safeguard the human settlers from the occasional raging raids by hungry animals. Fencing is expensive and to some extent disrupting, but it may be the price to pay for preserving nature while favouring the much needed progress in African countries that struggle to move forward.

Still, some places retain the charisma of an open and limitless land. Masai Mara National Reserve, located at a remote southwestern corner of the Kenyan territory, is one of the only places in Africa that yet show wildlife concentrations evoking the days of the great white hunters, when the whole East Africa was a free and wild hunting ground. The reserve is unfenced, hence animals find no obstacles to move at their whims, as long as permitted by their mates' territorial demarcations. No other limits exist, not even the national boundaries: wildlife wanders about through the 1510 km2 encompassed within the protected area, but also in the so-called dispersal area, north and east of the reserve, as well as in the adjoining Loita Plains and Hills, and further into the Serengeti National Park in northern Tanzania. All of it builds up what is known as the Serengeti-Mara ecosystem, comprising a 25,000 km2 worth piece of Africa.

Wildlife movements are highly conditioned by climate. The vast plains of Serengeti, which allow a wide dispersion of the large herbivore herds, receive seasonal precipitations that are not enough to support an all-year-round provision of forage. The wettests area of the ecosystem is the Masai Mara region, blessed by rains from November through June, with frequent storms throughout the year and the permanent water source of the Mara river. Thus, Masai Mara is a strong magnet for the large herds seeking fresh pastures, and this is the spark that triggers the great migration. Each year, up to 1.5 million wildebeest (or white-bearded gnu), 250,000 Burchell's zebra and half a million Thomsonīs gazelle trek through the Serengeti-Mara complex along a cyclic march that covers annually some 1,800 miles.

The migration is a relatively recent phenomenon. Before the 1960's, seasonal treks were observed by Dr. Bernhard Grzimek, who first described a definite pattern in the migratory moves. The wildebeest population boomed in the 60īs and 70īs, peaking from some 250,000 to the current nearly one and a half million, making the migration a massive display that could well rank top in a list of the world's nature wonders. Meanwhile, the native Maasai people try to rear their livestock in direct competition with what they call "the wild cattle", which they consider a calamity, since they transmit diseases to their own cattle and poison the waters with their foetal sacs.

When and where does the migration start? Strictly, the migration has not a start nor an end, each wildebeest's life in the Serengeti-Mara is a constant pilgrimage that is never over until the animal dies. Thus, the only beginning to consider is birth. During the wet season, Serengeti is a nice place to live in. Grass abounds on the southern plains and in the Ngorongoro Conservation Area, where the animals find a safe and sound place to graze and drop their calves. From late January to mid-March, along a six week period, 400,000 newborn wildebeests see their first light. Many are grabbed by jackals and hyena early after birth, and will never have the chance to experience their hiking fate. Survivors have scarce time to strengthen their legs, since the trek starts in April. By then, the rains are over in southern Serengeti and the plains have dried up. The great herds then gather and face the long march northwards and westwards.

The solemn procession will not travel alone: a constellation of carnivores will follow closely, mainly lion and hyena, whilst the vulture squadrons overfly the parade. Thousands of weak or ill animals will end up devoured during the trek, and only one out of three calves will ever see the Serengeti again.

Under the command of a mysterious shepherd God, the lawn mowers abandon the exhausted grasslands of southern Serengeti to head for the tall grass of the Western Corridor, near the shores of Lake Victoria. Compenetration between wildebeest and zebra is perfectly accomplished and biologically favoured, since zebras enjoy the long woody stems that wildebeests refuse.

In late May, the herds leave the Western Corridor to take the northern Serengeti plains and woodlands, where they exhaust the prairies smelling the rains that are falling northward, at the other side of the humans' border, in Masai Mara. The fresh, tender and mineral-rich pastures are the irresistible bait for the wild cattle to finally invade the Kenyan reserve, an event which usually starts in late June to early July. The troops coming from the south meet here another migratory contingent: the resident wildebeest herds of the Mara region. These animals, adding up to 100,000, reside in the Loita Plains and Hills, northeast of the Mara, until the dry season brings the tougher days and it is time to seek the evergreen Mara basin.

Throughout the month of July, the herds cross the Sand River, a mostly dry tributary of the Mara which roughly follows the boundary line between Kenya and Tanzania. The parade thus takes the eastern sector of Masai Mara, surrounding the Keekorok Lodge area. The trek follows westward, leading the herds to face the major challenge along their quest: crossing the Mara river and frequently also its tributary, the Talek. By then, the rains at the Mau Escarpment, where the Mara rises, have fed the stream to its highest levels. The steep banks are populated with trunk-looking basking crocodiles that seem almost to be expecting their annual banquet.

The operation of fording the river is the most delicate along the migration, and as such seems to plunge the gnus in a state of anxiety that only relieves when the whole herd has crossed. It is a very enjoyable experience to observe the highly social and gregarious behaviour of these animals, resembling more a flock for its coordinated movements. The trekkers walk along the left (eastern) bank of the Mara looking for a suitable point to cross. There are plenty of preferred crossings along the course, which are easily identifiable by the lack of vegetation, the depressed slopes and the deep grooves carved by the animals' hooves. These are the most secure places to ford the river, those that ensure a minimal mortality. Nonetheless, the apparent programming of the whole process sometimes seems to collapse, and the nervous herds occasionally choose places where the banks are too steep and many of the animals break their legs down the cliff or fall flat into the waters.

The herds gather at the suitable points and wander around nervously, their grunts sounding loud in the air. Eventually, one animal takes the lead and approaches the rim, scanning the opposite edge to analyze if any danger awaits after the crossing. When it finally dives into the stream, this seems to haul the rest of the herd. More animals follow in a single line across the river, while the lagged ones throw themselves towards the stream until the rearguard pushes the troops to a frantic race that ends up with some animals trampled to death, lying aside the course.

During the ford, if only one single animal detects any danger, it will jump back pulling the rest of the herd to a general retreat that sometimes brings panic and triggers a crazy stampede. When the line breaks, the animals that have successfully crossed will not follow their trek until the whole herd has passed: they will remain at the opposite bank, grunting at their mates as if encouraging them to cross. Occasionally it is the zebra minority who takes the responsibility of keeping the herdīs cohesion, even though these animals are clearly infrarepresented. In fact, zebra are not actually herd animals, rather they form small groups headed by a dominant stallion, but during the migration they seek the herd's protection, mixing themselves up with the wildebeests to such an extent that they seem to be fully identified with their white-bearded pals. Finally, once the herd has resumed the crossing, the leaders head on towards their unknown destiny.

The fording has finished and some animals have died, smashed to pieces by the crocodiles' jaws or trampled by their mates. The crossing, as determined by the wildebeest's survival instinct, ironically brings many of them to an end. Vultures and marabou storks become then permanent dwellers of the river banks where carcasses decay. The disgusting massacre landscape, that literally stains in red the chocolate waters, is nothing but one more step in the circle of nature, actually it is not a scene of death but one of life, since the abundance of meat feeds a great lot of species and controls the herbivores' populations.

Along the boreal summer, the crossings repeat over and over, and the survivors graze peacefully on the Mara Triangle grasslands unless disturbed by the early-morning and late-evening hunts of lion and cheetah, the latter preying on the calves. At night there is an additional threat: hyenas, which despite their fame of carrion-seekers, gather in groups to siege the herds, frequently losing their prey to lions after the sunrise.

By October, the rains are heading south back to Serengeti. This is when the pace of the march reverses, bringing the herds to face once more the quest for the southern grasslands. The rite of fording the river is again part of nature's call. In the last days of October, the migration is on to the vast plains of southern Serengeti, where a new generation of calves will be born to start the cycle of life all over again.

From July to October, the image of the wildebeest columns traversing the plains is one of the most beautiful the visitor can watch in Masai Mara. The large herds populate the grasslands while we drive along the reserve's roads and tracks, and any lookout conveys the superb display of the lines crisscrossing the landscape in different directions. The choreography reaches its top splendour when seen from above, from one of the balloons that fly with the first morning lights.

The banks of the Mara are flanked by tracks from where, with a little bit of luck and a good dose of patience, you can catch a thrilling glimpse of the herds crossing the river. The right (western) bank is bordered by a track that starts in the north, near Oloololo Gate, and follows the stream southward through Mara Serena Lodge to the New Mara Bridge, at the south limit. At the left (eastern) bank there is a track from Governor's Camps that borders the Mara down to the junction with the Talek. A brief study of the columns' movements through the grasslands will give you a hint on possible fording sites. Once you have located an area in which animals concentrate, look for a point where the traces of crossing are evident. If possible, choose the "departure" bank rather than the arrival one, since wildebeests will never cross if they detect any danger awaiting at the opposite side, and a vehicle is certainly a threat. If you are bound to the "arrival" bank, choose a vantage point above a bend of the river, a place that allows you to watch the crossing from behind. Hide your vehicle among the bush, get your camera ready, sit back and enjoy.