Each June on Tanzania’s Serengeti plains, animals resume a journey they’ve been making for millions of years. It’s the drying of the grasses that triggers them and the scent of rain in the north that beckons them. Then, as if a herdsman had cracked a whip, wildebeest, zebra, gazelle and antelope sweep over the plains, and for a few weeks the Serengeti thrums with hoofs pounding against hard earth. These are sounds our hominid ancestors would have heard. And it is a scene they may have watched from a hillside overlooking the plains.
This is the largest mammal migration on the planet, and although ecologist Tony Sinclair and I had witnessed it on other occasions, we were still dumbstruck by the huge number of animals massed together. We were nothing more to them than a rock, an obstacle in their path. Our Land Rover parted their flood, and then the parted streams merged back together and the wildebeest continued en masse, doing what they have always done: eating their way across the plains, as much a force of nature as a wildfire or sudden storm.
It is this migration that many people picture when they think of wild Africa, and it was this migration that led the British colonial government to create the Serengeti National Park in 1951. By saving the Serengeti, one of the park’s advocates wrote, they would preserve a small remnant of Africa’s “original splendor, so that the black and white men who follow us will be able to see it in its awe-filled past glory.”
“They thought the Serengeti was untouched, ‘primeval’ Africa,” said Sinclair, an ecologist at the University of British Columbia at Vancouver. His 40-plus years of study here have left him weathered and freckled, and earned him the nickname Mr. Serengeti. “But of course it was neither of those things. We—humans, that is—had shaped it to a great degree, although no one realized it at the time.”
Sinclair pointed to the wildebeest around us. “The wildebeest population now is about one and a half million,” he said. “In the 1960s there were barely 200,000.” After dropping to this low point, the wildebeest numbers began to rise again, as did the buffalo population. “The wildebeest and buffalo were increasing by leaps and bounds. And that’s why the park service invited me here. They wanted to know why.”
In pursuing that question, Sinclair discovered two things about the Serengeti that had escaped the park’s founders. The first is that this land is far from being a slice of unchanged nature, a part of the wild frozen in time. “Everyone looks at the Serengeti and wants it to be lasting and unchanging,” Sinclair said. “It may very well last, but it will most certainly change.” The second is that wildebeest—these most unlovely ungulates with their scruffy beards and tails, twisted horns and goggle eyes—play the crucial role in the dynamic life of the Serengeti. “Without the wildebeest, there would not be a Serengeti. They are its lifeblood.”
It’s relatively easy to understand how the wildebeest might affect something like the number of lions in the park. The ungulate is one of the biggest meals a lion can bring down; at the height of the migration, lions need only wait by a gully or river crossing, then slap out a paw to put meat on their table. They lie brazenly on the roads, fat and dazed from the gorging. This leaves the wildebeest nervous and alert. A herd may be loping along rhythmically one moment, seemingly oblivious to anything other than the need to move, and in the next is heaving with panicked animals darting this way and that, trying to escape.
Once, some years ago, I camped with Sinclair, his wife, Anne, and his colleague Simon Mduma of the Tanzania Wildlife Research Institute on the banks of the Serengeti’s Grumeti River. The migration was coming to an end, and several big herds of wildebeest settled near our tents for the night. I listened to them snorting and shuffling about, and then I heard the first lion’s roar. Actually, I felt rather than heard it, the deep rumbling coming up through the ground as if the earth had a bad, dry cough. More lions joined in, and the thin walls of my tent seemed to vibrate with their roars. Involuntarily, I curled into a fetal position. My breathing sank to something less than shallow. Here I was, a skinny, little, clawless, hornless primate...on the ground. “Take the wildebeest,” my racing heart chanted. “Take the big, fat, succulent wildebeest.”
Maybe that’s what the panic of the wildebeest is about: “Take him! Not me!”
Had the increased number of wildebeest led to a greater number of lions? I now asked Sinclair.