Exactly where and when a crossing will occur is a bit of a guessing game, but there are crossing points that are typically used, and when large numbers of wildebeest begin to gather along the banks of the river, that might signal that a crossing may be developing. Of course, what triggers an actual crossing is more of a mystery, but clearly something happens that starts them off. Not dissimilar to watching a large flock of geese in the early morning, where presumably one bird just decides to go first, and suddenly there are thousands of geese taking to the air. Here it seems obvious that a) they all want to get to the other side of the river, and b) they are terrified at the prospect of actually crossing, since there are likely dozens of crocodiles lying in wait for them to do just that.

The Mara River originates in the Mau Escarpment, along the western edge of the Great Rift Valley in southern Kenya, meandering southwest some two hundred and forty miles through Kenya’s Masai Mara and Tanzania’s northern Serengeti before emptying into Lake Victoria. It is a defining feature of the great annual migration of wildebeests and zebra in the Serengeti plains of Tanzania.

The migration is a huge, clockwise (more or less) movement of thousands of wildebeests and zebra, starting in the southern Serengeti plains to the west of Ngorongoro Crater, where the wildebeest birthing grounds are located. Over the year they move north towards Kenya’s Maasai Mara, following the pattern of the rains, and the fresh grasses they bring. Later in the year the rains move back south, with the wildebeest and zebra following, completing the circle.

Witnessing a crossing of wildebeest at the Mara River in northern Tanzania during the Great Migration can overload the senses, a raucous cacophony of sound and motion, but within which are embedded multiple smaller, but poignant stories. Some become marooned on large rocks in the middle of the river, unsure or afraid of moving forward or backward. A mother zebra, after crossing once, becomes separated from its foal who for some reason did not cross. She crosses back to retrieve its foal, then re-crosses a third time to bring the foal to safety, all while somehow avoiding the many crocodiles lurking in the waters. Crocodiles stockpiling dead wildebeest in the river’s shallows, and returning back to the maelstrom for another. A Yellow-billed Stork quietly and methodically fishing as if nothing was happening. And once the crossing is largely over, groups of wildebeest calves form along the river bank, plaintively bleating for their lost mothers, some of whom may have perished in the river, others not making the crossing at all.

In the midst of the cacophony we watched a wildebeest, separated from the majority of those crossing, get attacked by a crocodile mid-stream. At first it seemed that this story would end quickly. But as the minutes passed, the wildebeest slowly fought to make it to the shore, its back sheared open, horribly mutilated, dragging the crocodile who seemed to be slowly losing its grip. How did any of this make sense? We were all of us, all of the vehicles that had gathered at this crossing, cheering the wildebeest on, the children in the vehicle next to us screaming and crying in terror. And yet the wildebeest slowly so slowly, stepped on to shore, finally shaking the croc loose.

The sun was setting. We were exhausted from just watching. Those that had successfully made it across the Mara gathered in the plains, seemingly congratulating each other in their success. The lost calves continued their plaintive bleating for their missing mothers. And our hero wildebeest slowly made his way out onto the plains, where waiting for it, as the night fell, were the lions and hyenas . . .