WHY IS THE WILDEBEEST THE DOMINANT HERBIVORES IN SERENGETI?

This animal has evolved a number of adaptations that enable it to exploit these environmental conditions more efficiently than competing herbivores. With its wide row of incisor teeth the wildebeest can harvest more grass per mouthful than practically any grazer.

However, large concentrations quickly exhaust a pasture and so wildebeest aggregations have to keep moving. Thus the migration is a continuous quest for greener pastures and water which take the wildebeest  over an annual circuit of approximately 800kms and covers a much greater distance when daily local movements to and from are taken into account.

There is general movement off the plains as soon as the grasses lose their green flush. As the dry season intensifies, the population moves further north and west toward Lake Victoria into areas where there is permanent water and thunder storms are most likely to occur out of season. Toward the end of the dry season in July most of the populations have ended up in the Kenya Mara.

The most impressive and probably the most reliable migratory event is the mass movement of the Serengeti plains that occurs at the beginning of the long dry season, typically May or June. Lines and columns of wildebeest up to 40km long have been observed (from air) heading southwest, north or west as the wildebeest trek to the woodland zone.

The annual wildebeest breeding season or ‘rut’ often coincides with the migration off plains. In a period of only three weeks around 90% of the cows, some 400,000 wildebeest are bred. It is fascinating to see and to hear thousands of territorial bulls, with as many as 280sq.km, rounding up cows, cutting out bachelor males and bashing heads with territorial neighbors in all-out effort to breed with as many females as possible.

Eight and a half months later the cows drop their calves, preferably on te short grass plains. The wildebeest calving season is another outstanding spectacle. Unlike most antelopes who seek cover when giving birth, pregnant wildebeest gather on the most open terrain available and dozens of calves may be born every morning on these calving grounds. Calves can stand within 7 minutes on average, and remain with and dependent on their mothers for at least six months and often up to a year. Cheetahs and wild dogs can easily run down older calves, but hyenas and lions look for new ones. After about days the calves are so hard to catch that the spotted hyenas the main wildebeest predator, seldom bother with them. The wildebeest’s short calving season, something unusual in the tropics, seems designed to surfeit predators at one time and not give them a steady supply of calves throughout the year.