The causes of the Pleistocene megafauna extinctions in the Americas have been debated for decades.

The two main hypotheses — climate change as the primary driver, and human hunting pressure (sometimes called overkill) as the primary driver — both have evidence in their favor and are not necessarily mutually exclusive.

The timing of the extinctions correlates with both the end of the Ice Age climate shift and the spread of human populations across the Americas.

Whether it was the changing climate, the hunting, or the combination that drove the gomphotheres and the ground sloths and the mammoths and the horses and the camels and the dozens of other large mammal species to extinction is still actively debated.

The presence of gomphothere bones in the same chamber as the bones of a human being who was alive at the end of the Pleistocene is a reminder of how close in time the earliest well-documented Americans and the last of the megafauna actually were.