The sun going north after the equinox causes a northeast monsoon, and the meeting of northeast and southeast monsoons produces rain; the winds, colliding, are driven upward, and in the cooler atmosphere, discharge their water. In summer a hard southeast monsoon comes from cool latitudes of open ocean east of Madagascar, and because the meeting of monsoons takes place over the south Sudan and Ethiopia, rain is scarce in the Crater Highlands. But distant anvil clouds and cumulo-nimbus herald the separate weathers of the lake basin, and by late spring the plains animals are already moving down the drainage lines that flow west toward the woodlands. In November, when the northeast monsoon swings southward and the Pleiades appear, white clouds rise on the eastern sky. Then the short rains fall, and the great herds, drawn by the first flush of new grass, return to the open plain in the annual movement, known as the “migration,” that serves as pasture rotation for the wild animals.
In the winter of 1961, when I first visited the Serengeti, the greatest drought in memory was in progress. The short rains had failed entirely and the cow gnu or wildebeest, lacking milk, abandoned many of the calves; the following year there were no calves at all. But herd animals are adapted to calamities, and by the winter of 1969, when I returned to Seronera, their numbers had already been restored.* That January, the wildebeest were still moving eastward. The endless companies of animals, filling the sullen air with sullen blarting, are divided into cow-and-calf herds and herds of bulls; the bull gnus, especially, are wildebeests in their behavior, leaping, kicking, scampering, bucking, exploding crazy-legged in all directions as if in search of stones on which to dash their itching brains.
Often the wildebeest are accompanied by zebra. The striped horses, which foal all year instead of in a single seasonal avalanche, have less young to look out for and more intelligence to look out with; it is rare to see a zebra foal lost from its family band of stallion and mares. But among the gnu, the bony-legged calves are hard put to it to keep pace with their foolish mothers, and are often lost among the milling animals. Once separated, they are doomed, and fall to the predators in short order. The very plenty of their numbers in the few weeks of the calving may help preserve the species: the predators are too glutted to take advantage of all the opportunities, and many calves survive to blart another day.
Many wildebeest, streaming toward the highlands, cross the south end of Lake Lagarja, the headwaters of the Olduvai stream that cut the famous gorge; like almost all lakes of this volcanic region, it is a shallow magadi or soda lake of natron—native sodium carbonate in solution. In the low woods by the donga that drains the plateau to the west, a family of five cheetah lived that winter in the airy shadow of umbrella thorn, and greater and lesser flamingos, drawn to the soda lake’s rich algal broth, rose in pink waves between the dark files of animals crossing the water. Since gnu are ever willing to stampede, the crossing is a hazard for the calves, and one morning of early winter more than six hundred drowned. Death passed among them like a windstorm, and its wake was awesome, yet the carcasses littered along the lake shore were but a third of one per cent of this antelope’s annual regeneration in the Serengeti. Bloated calves had been dragged ashore by lions and hyenas, and others floated, snagged on mud reefs in the foamy shallows. In the thick heat of central Africa a stench so terrible clings to the throat; death had settled in the windless air like a foul mist. Among the carcasses, probing and sweeping, stepped elegant avocets and stilts, ignoring the taint in the stained water, and vulture and marabou in thousands had cleared the skies to accumulate at the feast. These legions of great greedy-beaked birds could soon drive off any intruder, but they are satisfied to squabble filthily among themselves; the vulture worms its long naked neck deep into the putrescence, and comes up, dripping, to drive off its kin with awful hisses. The marabou stork, waiting its turn, sulks to one side, the great black teardrop of its back the very essence of morbidity distilled. With George Schaller of the Serengeti Research Institute I made a count of the dead calves, and the vultures gave ground unwillingly, moving sideways. Vultures run like gimpy thieves, making off over the ground in cantering hops, half-turned, with a cringing air, as if clutching something shameful to the stiff stale feathers of their breast. The marabou, with its raw skull and pallid legs, is more ill-favored still: it takes to the air with a hollow wing thrash, like a blowing shroud, and a horrid hollow clacking of the great bill that can punch through tough hide and lay open carcasses that resist the hooks of the hunched vultures. Vultures fly with a more pounding beat, and the cacophony of both, departing carrion, is an ancient sound of Africa, and an inspiring reminder of mortality.
Dr. Schaller, a lean, intent young man whose work on the mountain gorilla had already made his reputation, was studying the carnivores of the Serengeti. In the winter of 1969, he spent as much time as possible in the field, and often he was kind enough to take me with him. Usually we were underway before the light, when small nocturnal animals were still abroad—the springhares, like enormous gerbils, and the small cats and genets. The eyes of nocturnal animals have a topetum membrane that reflects ambient light, and in the headlights of the Land Rover the eyes of the topi were an eerie silver, and lion eyes were red or green or white, depending on the angle of the light. The night gaze of most animals is red, like a coal-red beacon that we once saw high in the branches of a fever tree over the Seronera River; the single cinder, shooting an impossible distance from one branch to another, was the eye of the lesser gallego, or bushbaby, a primitive small primate which may or may not resemble the arboreal creature from which mankind evolved.
In a silver dawn giraffes swayed in the feathery limbs of tall acacias, and a file of wart hog trotted away into the early shadows. Where a fork of the river crossed the road, a yellow reedbuck and a waterbuck stood juxtaposed. With its white rump and coarse gray hair, the waterbuck looks like a deer, but deer do not occur in Africa south of the Sahara; like the wildebeest, gazelles, and other deer-like ruminants, from the tiny dik-dik to the great cowlike eland, the reedbuck and waterbuck are antelope, bearing not antlers but hollow horns: the family name, Antilopinae, means “bright-eyed.” All antelope share the long ears, large nostrils, and protruding eyes that together with speed help protect them against predators, but non-migratory species such as topi, waterbuck, and kongoni seem more vigilant than the herd species of the green plain.3
At Naabi Hill, the wildebeest were moving east after the rains. In their search for new growth, wildebeest are often seen trooping steadfastly over arid country toward distant thunderstorms, which bring a flush of green to the parched landscapes. Some two hundred thousand were in sight at once, with myriad zebra and the small Thomson’s gazelle. Eight wild dogs were hunting new gazelle left hidden by their mothers in the tussocks; one snatched a calf out of the grass only yards from the tires of the Land Rover, and with the two nearest dogs tore it to bits. The death of new calves is quick; they are rended and gone. But one calf older than the rest sprang away before the dog and made a brave run across the plain in stiff-legged long bounces, known as “pronking,” in which all four hooves strike the ground at once. Like the electric flickering of the flank stripe, pronking is thought to be a signal of alarm. Though its endurance was astonishing, it lasted so long because most of the dogs were gorged and failed to cooperate. While the lead dog snapped vainly at the flying heels, the rest loitered and gamboled, picking up another calf that one of them ran over in the grass.
The Land Rover, dodging humps and burrows, followed the chase across the plain. Schaller clocked the young gazelle, which dodged back and forth for two and a half miles on the car’s gauge and more than three in actuality; it never ran in a straight line. (The zigzag is less an evasion tactic than a way of seeing out of eyes set back on the sides of the head; in a herd, pursued animals usually run straight out.) The calf’s spirit tempted us to intervene but we did not, since it was doomed whatever happened; separated from its milk when the chase began, it would have gone hungry while awaiting the first of
the many beasts and giant birds that would come for it on sight. Finally, two dogs moved up to flank the leader, and in moments, the chase was over. The calf, still bouncing desperately, veered back and forth across the paths of the spurting dogs, and the dog to the eastward snatched it from the air; the other two were on it as it struck the ground.
One day, by a depression that holds water in the rains, I found a chipped flake of obsidian, much used by primitive man for his edged tools. There is no obsidian on the plain; the chip had been brought here long before. I wondered about the men who brought it—what size and color were they? Were they in hides or naked? What cries did they utter? Staring at the sun, the sky, were they aware of their own being, and if so, what did they think?
Doubtless the primitive hominids whose remains have been found at Olduvai were drawn to the edge of the great plain by the legions of grazing animals, and doubtless they were glad of a bit of carrion. The hunter Frederick Selous, in the 1870s, was appalled to see natives eat meat of an elephant eight days dead—“Truly some tribes of Kafirs and Bushmen are fouler feeders than either vultures or hyenas”4—but accounts of life on rafts and in prison camps, in plague and famine, make clear that the most civilized man will eat both carrion and his own kind when survival is at stake, as it must have been each day for low-browed figures who lacked true weapons and perhaps language, despite the physical capacity to speak. (Perhaps the earliest Homo sapiens of the Old Stone Age had no fire, and the gift of flame from the supreme Creator, recognized by almost all African tribes, was an earthshaking event that is still remembered in the myths.)5
Traditional theories of the social life of earliest man are based on the behavior of non-human primates, although the apes are essentially vegetarians, and have lived very differently from man for more than a million years. Social systems, which often differ greatly among closely related creatures, tend to evolve in response to ecological conditions, and George Schaller felt that much might be guessed about early man from a comparative study of the social carnivores,6 which also pursued game in open country. While unable to run down his prey in the way of the wild dog or hyena, or even rush it swiftly as the lion does, man would have used such lion tactics as driving, ambush, and encirclement, and come upwind to the quarry, as lions have never learned to do. And as with the carnivores, a successful kill would inevitably depend on the social group that would share the food.
To judge from remains of predators found at his sites, early man was an increasingly effective creature who drove such unaggressive daylight hunters as the cheetah and the wild dog from their kills. In the dark, he was at a disadvantage and took shelter, leaving the hunt to leopard, lion, and hyena, but in the day, confronted with his sticks and stones, strange upright stance, and the shrieks, scowls, and manic jumps of primate threat display, these more dignified creatures probably gave way.
To learn how hunter-scavengers might fare, we sometimes walked some fifty yards apart for two hours or more over the plain. On most of the hunts gazelle calves were plentiful—with throwing sticks, four or five could have been killed, and with bolus stones (found at Olduvai) still more—and it was almost always possible to locate food by watching vultures in the distance. One day we came upon a Thomson’s gazelle, dead of disease, that the carrion-eaters had not yet located, and also a young Grant’s gazelle that must have been taken by the two huge lappet-faced vultures that we drove away, for the kill was fresh and no predators were anywhere about. Another day, when Schaller was elsewhere, I saw from a distance the white belly of a female Thomson’s gazelle, fresh dead. As I approached, the first vulture, a big lappet-face, came careening in and took a swipe at her white flank. The vulture was instantly driven off by a second female gazelle; the great bird, flop-winged, chased its assailant but did not renew its assault on the dead animal.
The gazelle was still warm, and I slit open the belly to see if she had died in calving. She had milk but no calf; the wet newborn thing crouched in the grass some twenty yards away. A half hour later, her companion was still on guard, but more vultures were gathering, and finally the body was abandoned to a motley horde of griffons, white-backs, and hooded vultures that stripped it to the bones in a few minutes.
Jackals, vultures, and hyenas are alert for the defenseless moment when a new calf is born; often hyenas will attend the birth. But one day there was a mass calving of wildebeest in a shallow valley like an amphitheater between the isles of rocks, and it may or may not be significant—I simply record it—that the calving took place in the very middle of the day, when the sun was high and hot and the plain still. There was no predator in sight for miles around, nor a single vulture in the sky. Cow wildebeest were down all over the place, and a number of tottery calves less than an hour old swayed and collapsed and climbed again to their new feet. By late afternoon, when the predators become restless, raising their heads out of the grass to sniff the wind, these calves would already be running. (Wildebeest calves can usually run within ten minutes of their birth, but even this may be too slow; I have seen a lioness, still matted red from a feed elsewhere and too full to eat, walk up and swat a newborn to the ground without bothering to charge, and lie down on it without biting.)
For fear of scattering the cows, I restrained a desire to go close, for the calves will imprint on the nearest moving thing and are not to be deterred. One day, I was followed from a grazing herd by a young calf, and my efforts to lead it back to safety finally resulted in putting the herd to flight. The calf did not follow, and the herd forsook it; nor would it permit itself to be caught. Finally I too left it behind. A mile away I could still see it—I can still see it to this day—a thin still thing come to a halt at last on the silent plain.
The unseasonal rains of late January continued into February, falling mostly in late afternoon and in the night; many days had a high windy sun. In this hard light I walked barefoot on the plain, to feel the warm hide of Africa next to my skin, and aware of my steps, I was also aware of the red oat and red flowers of indigo-fera, the skulls with their encrusted horns (which are devoured like everything else: a moth lays its eggs upon the horns, and the pupae, encased in crust, feed on the keratin), the lairs of wolf spiders and the white and yellow pierid butterflies, like blowing petals, the larks and wheatears (Olde English for white-arse), the elliptical hole of the pandanus scorpion and the round hole of the mole cricket, whose mighty song attracts its females from a mile away, the white turd of the bone-eating hyena, and the pyriform egg of a crowned plover in water-colored camouflage that blends the rain and earth and air and grass.
Bright flowers blowing, and small islets of manure; to the manure come shiny scarabs, beloved of Ra (god of the Sun, Son of the Sky). The dung beetles, churning in over the grass, collide with the deposits of manure, or attach themselves to the slack ungulate stomachs full of half-digested grass that the carnivores have slung aside. They roll neat spheres of ordure larger than themselves and hurry them off over the plain. Here dung beetles fill the role of earthworms: the seasonal droppings of hundreds of thousands of animals, most of which is buried by the beetles, ensures that the soil will be aerated as well as fertilized.
By morning the ground is soaked again and the tracks muddy. Frogs have sprung from fleeting pools, and the trills of several species chorus in the rush to breed. Companies of storks, nowhere in evidence the day before, come down in slow spirals from the towers of the sky to eat frogs, grass-mice, and other lowlife that the rains have flooded from the earthen world under the mud-flecked flowers.
The grassland soil is built of ash blown westward from the volcanoes of the Highlands. Beyond the ash plain, in the vicinity of Seronera, the soil is derived from granitic rock and supports an open woodland vegetation. This is some of the oldest rock on earth—certain granites here are two to three billion years old—and on the plain the bone of Africa emerges in magnificent outcrops or kopjes, known to geologists as inselbergs, rising like stone gardens as the land around them settles, and topped sometimes by h
uge perched blocks, shaped by the wearing away of ages. The kopjes serve as water catchments, and in the clefts, where aeolian soil has mixed with eroded rock, tree seeds take root that are unable to survive the alternate soaking and dessication on the savanna, so that from afar the outcrops rise like islands on the grass horizons. In their shadows and still compositions, the harmonious stones give this world form.
When the sun has risen and the morning’s hunt has slowed, the cats may resort to the rock islands. Perhaps they seek shade, or the vantage point of higher elevation—for the leopard its kopje is a hideout between raids—or perhaps, like myself, they like their back to something, for especially in summer, when the herds have withdrawn into the western woodlands and a dry wind blows in the dry grass, the granite heads are a refuge from the great emptiness of the plain. Kopjes occur in isolated companies, like archipelagoes—one group may be ten miles from the next—but most groups are related to a rising spine of rocks that emerges more or less gradually from the ash plain, from the low Gol Kopjes in the east to the majestic Morus at the edge of the western woodlands. Highest of all is Soit Naado Murt (in Maasai, the Long-necked Stone), nicknamed Big Simba Kopje, which juts straight up a hundred feet or more near the center of the spine, just off the main road from Olduvai to Seronera.
The Tree Where Man Was Born Page 10