Before we follow the controversy that erupted over Kennewick Man’s bones, we need to spend time in the world he actually inhabited — because that world was stranger and more complex than most people ever imagine, and understanding it is essential to understanding what his existence meant.

Eight thousand years ago, North America looked different from the world we know.

The great ice sheets that had once covered Canada and much of the northern United States had retreated several thousand years earlier, leaving behind a transformed landscape of new rivers, new lakes, and newly exposed land that plants and animals were still moving into.

The Columbia Plateau, by 8,400 years ago, had been ice-free for several thousand years and was being slowly colonized by the forests and grasslands and river ecosystems we would recognize today.

But the world was still adjusting to the end of the Ice Age.

Sea levels were different.

Coastlines were in different places.

The Pacific coast of North America — where Kennewick Man’s diet suggests he may have spent significant time — extended further west into what is now ocean.

Ecosystems were shifting.

The great Pleistocene megafauna — the mammoths, the mastodons, the ground sloths, the American horses and camels — had gone extinct just a few thousand years before Kennewick Man walked the earth.