A River of Animals

Polly woke to a sound like distant thunder that never stopped. It was voices. Wildebeest grunt to each other constantly as they walk, a low engine hum made of a million animals. From her acacia she watched the columns pass, five and ten animals wide, reaching from one edge of the world to the other. This is the great migration. It does not begin anywhere, and it never truly ends.

She dropped from the tree and flew into the dust above the herd. Then, carefully, she landed on the back of a big female wildebeest and rode along like a sailor on a slow ship. Nobody minded. Small birds ride wildebeest all day here, picking off flies. The animal's warmth came up through Polly's feet, and her blue-teal wings and round black-rim glasses turned gold with dust.

The herds eat in teams, in a fixed order. Zebras go first. They have strong teeth and can chew the tall, tough grass that others refuse. Wildebeest follow and eat the middle of the plant. Gazelles come last and take the fresh new shoots that appear after the bigger mouths have passed. One plain, three sittings, nothing argued over. Scientists call it grazing succession. It looks like very good manners.

In the late afternoon, far to the north, clouds stacked up dark and tall. The wildebeest cannot see grass beyond the horizon, but they can smell rain from enormous distances, and rain means grass. The whole grey river leaned toward the storm. Polly hopped off her ride, thanked it with a small bow, and flew up to find a tree for the night.