In pursuit of the 7th wonder of the world

In the weeks to come, the Masai Mara will host the spectacular wildebeest migration as they cross the swollen, crocodile-infested Mara River.

In mid November 2006, a panel of experts and a major American television network declared the annual wildebeest migration in East Africa one of the new ‘seven wonders of the world.’

Wildebeest are sometimes referred to as “the clowns of the plains” because they just don’t look very balanced. An old African myth has it that after God created all the other animals; He created the wildebeest, to get rid of the leftovers from the other animals.

That’s why the wildebeest has the head of a buffalo, the back of a rhino, the rear of a warthog, the legs of an antelope and the tail of a horse. From the vast Serengeti plains to the champagne-colored hills of Kenya’s Masai Mara, every year millions of wildebeest, zebras and gazelles roam, pushing ever forward in a clockwise rotation and encountering friend and foe along the way.

High drama

The great migration begins with a short calving season lasting two to three weeks, between late January and mid-March around the Ngorongoro Conservation area, southeast of the Serengeti National Park.

Here the 1.8 million wildebeest enjoy their favorite meal of the long red oat grass that grows in high-alkaline soils.

Giving birth starts abruptly and is remarkably synchronized; 500,000 calves are born in just two to three weeks. A few are born ahead of time, but hardly any of them survive as they are easily seen by predators and are an easy kill.

The females (cows) do not seek isolation from the herd during calving. The wildebeest society is much more structured at this time in groupings of pregnant cows, cows that have calved, yearlings recently separated from their mothers and bachelor herds.

Expectant cows gather and drop their calves before midday when it is very hot and the predators are resting under the shade (very few are born after midday).

Labour will last 30 minutes to one hour. When the calf’s head and trunk emerge, gravity will complete the process as long as the cow is standing.

Once the calf is dropped, it will be on its feet within three to five minutes and immediately seeks its mother’s udder.

After suckling, the mother may walks away to encourage the calf to follow, and five to 10 minutes after birth the calf is able to keep up with the pace of the rest of the herd.

Only 15 minutes after birth, the calf is able to run fast enough to beat our renowned Kenyan runners. The calf eats its first grass at about 10 days, although it is still suckles for at least six months.

Even after weaning, it will stay with the mother throughout its first year all along the great migration until the next calf is born. At that time the young males are driven away by territorial males, but the females often remain in the same groups as their mothers.

Imprinted on the mother

The calf is imprinted on its mother starting with the first successful suckling. It recognizes the mother by scent and sound. A cow will never adopt a calf and will totally reject it, even if she has lost her own calf.

A calf under six months will not survive on its own since it relies on its mother’s milk. Surprisingly, in this super herd of over 2.3 million members, 95 per cent of lost calves reunite with their mothers.

March to May: The herds begin to swoop west and north towards the long grass plains and woodlands of the Serengeti’s western corridor.

The dangerous routes of wildebeest migration are not always easy; there is high drama almost the whole time. With the cycle of life comes the promise of death. Lions, cheetahs, wild dogs, leopards, hyenas, vultures and crocodiles look forward to the arrival of the herds.

Here they are joined by friends; 500,000 zebras and 100,000 plains game, most of which are Thomson’s gazelles and Grant’s gazelles. There is even a pattern to the way they eat.

First, the zebras eat the top part of the grass, and then the wildebeest go for the middle and then the following plains game like the gazelles go for the lowest part.

By the end of May rains start to end, and the rutting season begins at this time when males are in their prime. The bulls are territorial at four to five years old.

During rutting they undergo dramatic behavioral changes, becoming the noisiest and most active of all African antelopes and are continually seen galloping about to show that they are in good health and capable of defending their territory.

Rutting in their prime ensures a high conception rate. If yearlings are well nourished, first conception may occur at 16 months.

Their gestation period is eight to eight- and-a-half months. The wildebeest has a higher conception rate than all other mammals — more than 95 per cent of mating succeeds.

A male will compete to gather and hold as many as 16 females as long as they are in his territory. He must mate quickly.

Being a prey species, he cannot afford to indulge in long and complex mating rituals because he has to reduce the chances of being caught in a compromising position by a predator.

During this peak of activity, he will not eat or rest as he has constant fights with neighboring males.

June to July is a transitional period between the rains and the dry season. As the animals concentrate on the remaining green patches of savannah, they push further northwards towards the Mara.

Wildebeest must make a daily trip to water whenever possible to help drive the great trek. They can drink eight liters of water in a single session if undisturbed.

Now, after four months of trekking, they are in desperate need of water and grass. Many of the young find it difficult to come this far, sometimes going for days without water.

Many die from exhaustion and thirst before they reach the Mara, but many also survive only to find one last huge obstacle in their way.

The final push results in amassing along the banks of the swollen Mara River, producing one of the world’s most spectacular sights: Millions of wildebeest and thousands of zebras and gazelles in between, all waiting to cross the crocodile-infested river.

Although it is commonly assumed that this is simply a frenzy and that the animals cross blindly, recent research has shown that a herd of gnu possesses what is known as a swarm intelligence whereby the animals systematically explore and overcome the obstacle as one.

Depending on rainfall sometimes the chosen crossing place is shallow, and most of the animals can cross safely. But often the river is deep and fast with steep banks either side as it is now after the heavy rains.

Many of the weaker animals are not able to cope with the strong currents or the buffeting from other wildebeests as they swim. Hundreds can die during crossing, littering the river’s edge with corpses.

July to October: The wildebeest are residents of the Mara, grazing the lush green grasses that the earlier rains encouraged. The mass of over two million wildebeest covers the savannah grasslands as far as the eye can see. It’s party time for the lions.

Predation by lions, leopards, African wild dogs, cheetahs and hyenas at this time is great simply because of the numbers.

October to November: The short rains begin to fall in the south and east of Serengeti, so the herds start to leave the Mara, crossing the Mara River again and meeting the same perils as before. Sometimes the migrating animals seal their own fate.

One group starts out going south but is then distracted when they sense rain to the north. The result can be crossing a river filled with unfriendly crocodiles over and over again, sometimes 10 to 20 times depending on which direction they are going.

Finally they head slowly back to the eastern Serengeti plains and by the time they arrive it is between late January and February, and the cycle is complete. Arrival at the calving grounds marks the end of this migration and the start of next year’s.

In all, 250,000 wildebeest die during this 1,800-mile journey. But the next calving will produce 500,000 new calves who must take their chances along with the adults on the next great migration.