Lay of the Land

How Science Works

one of the most perplexing mysteries of “recent” earth history is the rapid extinction of some 26 genera of large mammals known as megafauna at the end of the last Ice Age. About 13,000 years ago, giants like the wooly mammoth, ground sloth, and saber toothed cat disappeared from the Northern Hemisphere. At about the same time wily Clovis hunters armed with sophisticated stone spear points appeared in North America, prospered, and then disappeared.

In the 1960s, University of Arizona ecologist Paul Martin suggested that the Clovis hunters were primarily responsible for this mass extinction. A fierce debate has raged in archaeological and ecological circles ever since. In this issue of American Archaeology we examine a new theory (see “The Clovis Comet Controversy,” page 12). A group of scientists is proposing that a meteor or comet struck North America about 12,900 years ago, causing a new, little ice age known as the Younger Dryas. They argue that the resulting dramatic climate change caused the extinction of the megafauna and the decline of the Clovis people, as well.

Their theory has caused a robust debate that shows how science works. New theories require reexamination of old evidence. New technologies are brought to bear on old problems. New data collection is needed to look for new evidence on all sides of the issue. Thus we need well preserved PaleoIndian sites where the data is intact, and that’s what the Conservancy is trying to do at the new Cardy preserve in Wisconsin (see “Life During The End Of The Ice Age,” page 46) and other PaleoIndian preserves around the country.

Mark Michel, President