Serengeti National Park
One striking feature about the short and long-grass plains is the extraordinary mass and variety of grazing animals that can exist in one area simultaneously. This can be explained by a process known as the 'grazing succession'. The heavy grazerselephants, buffaloes and hipposeat and trample the large coarse grasses, causing changes that make the vegetation palatable to lighter grazerszebras, topi and wildebeestwho in turn prepare the vegetation for the lightest herbivoresgazelles and warthogs.
Going north from the Ngorongoro Crater Conservation Area, the short grassland of the eastern Serengeti plains gradually gives way to medium grassland, then to longer grassland up to 30 cm tall at Seronera. The transition zone is at Naabi Hill, where visitors sign in.
Throughout this part of the park you will see large sculptured earth mounds, which are built by termites. Termites are sometimes called white ants, but in fact are related to cockroaches.
Beyond Naabi you should see topi and kongoni or Coke's hartebeest, both typical residents of longer grassland and, like wildebeest, almost pure grazers. Topi and kongoni are very alike, but differ in color, head and horn shape. The Kongoni, taller and heavier, and fawn-colored with a pale rump, prefers the transition zone between the medium-grass plains and the woodland zone. Aggregations of up to 100 may be seen out on the plains on a post-burn flush and groups of 20 or more are often seen around Seronera.
The topi, whose color is a rich bay with blue-black markings on the rump and hind quarters, is most abundant on the floodplains where it does not have to compete with wildebeest. Topi and termite mounds seem to go together: Both males and females like to stand on the mounds to see and be seen. Kongoni also stand on mounds but less habitually. Other antelopes and zebras rarely do so.
The two species have quite different reproductive and social systems. Neither topi nor kongoni are truly migratory, but on the floodplains they may move up to 50 km between wet and dry season ranges. Males of both species defend permanent territories containing enough forage for a herd of females throughout the year. Territories of these two species overlap and bulls, when alone, often remain near each other. On the rare occasions that they interact aggressively, the topi dominates its larger relative. The kongoni is altogether a shyer, less assertive animal.
Kongoni breed throughout the year, though with clear peaks in the dry and wet seasons. Newborn calves spend most of their first month hiding in the grass, like nearly all antelopes. Topi have a well-defined calving season at the end of the dry season. Topi calves grow very fast. Yearling females can hardly be distinguished from adults by 16 months. At this age most females mate, and then calve at age two. Many males appear fully grown by two but few are mature enough to gain territories and breed before three years of age.
Some people think grazing animals are in a constant state of fear of predators. Although they always remain very wary, they seem to know when a predator is not actually hunting, and at such times show remarkably little nervousness provided the carnivore does not get closer to them than the limit known as the 'flight distance'.
Bat-Eared Foxes live in burrows in the open plains and although mainly crepuscular, may often be seen and recognized by their generally foxy appearance and very large ears. They feed almost exclusively on insects, but apparently eat roots, fruit and eggs from time to time. Bat-eared foxes give birth once a year, at the end of the dry season. Four cubs to a litter is typical but up to ten are occasionally seen.
There are just under a quarter of a million Thomson's and perhaps 30,000 Grant's gazelles in the Serengeti, and they are often seen together. The Tommy, as the Thomson's is affectionately known, is considerably smaller and redder than the Grant's. An easy way to distinguish these species is to look at the white marking at the rear of the animals. In Tommies the white comes up to the tail, whereas in Grant's it comes over the tail and onto the rump. Tommies of both sexes have strongly marked lateral stripes, whereas in the Grant's only the female is marked in this way. Grant's are larger and are pale fawn with white underparts. Horns are present in both males and females of the two species but are much larger in the male.
Tommies are the main prey of the plains-dwelling wild dogs and cheetahs and the staple diet of resident lions during the dry season when their preferred prey—zebras and wildebeest—have migrated out of reach. Hyenas and leopards also take their toll, while jackals are the main predator on young fawns of both gazelles. Unlike nearly all other antelopes, female gazelles will team up to defend their young against jackals, which often hunt in pairs. Newborn gazelle fawns are even taken by some of the larger birds of prey, including the martial eagle.
Both species spend a good deal of their time on the long-grass plains after a fire but will be seen in other areas of the Park. As they are capable of going for long periods without water, they often remain in the short-grass plains after the wildebeest and zebras have left.
Despite, or perhaps because of, their grotesquely ugly appearance, everyone has a soft spot for the Warthog, which is often seen in grasslands grazing on its knees. The warthog is strictly diurnal, spending the night in burrows, which they take over from other animals, often backing into the hole so as to be ready for any attack made on them by predators.
Warthog are fond of wallowing in mud, and have the amusing habit of running with their tails held erect when disturbed. They are usually seen in family groups with two to four young, but sometimes the previous year's young stay in the family. The enormous 'warts' growing on the faces of males give warthogs their name and like the enlarged upper tusks probably serve to keep opponents aligned head to head during combat between males.
The tall Secretary Bird is often to be seen pacing through the grassland in search of snakes and other reptiles, which it kills with a powerful stamp of its foot. It also eats large insects such as locusts and the eggs and young of ground nesting birds. The crest of feathers behind this bird's head is said to resemble the quill pens, which used to be carried behind a clerk's ear.
Secretary birds lay two large whitish eggs in a massive nest built of sticks and turf high in a flat-topped tree, often a considerable distance from the ground. These nests are used year after year, merely being renovated as the egg-laying season approaches.
The Ostrich is the world's largest bird and the only flightless bird native to Africa. Males are conspicuously black and white with naked necks and thighs, which turn bright pink during courtship. The breeding season extends from around August to December. Single males defend large territories, court females who enter—singly or in small groups—and guide them to a nesting hollow, where several different hens may lay up to 30 eggs, at the rate of one every other day. This is too many eggs for one ostrich to cover and the extras are left around the nest and fail to develop.
Incubation is divided into day and night shifts, the black male by night, the female by day when her neutral color makes her harder to see. The female who incubates the nest is known as the 'major' hen and is the first to lay an egg in the nest scrape. The young that hatch in December or January tend to band together and adult pairs may creche their young together, making flocks of up to 60 chicks.
Ostriches are very fast runners and are able to maintain their pace for a considerable time. This, together with the fact that they have the ability to swerve sharply, sometimes enables them to outwit predators such as lions, which are very fond of their flesh.
Details mentioned in this article were accurate at the time of publication