The present is the key to the past. Every geologist worth their sodium chloride knows this. The famous phrase, a distillation of the principle of uniformitarianism, can be seen emblazoned on mugs, bumper stickers, and more in college geology departments around the country. But while it’s true that phenomena currently in action can help us understand what transpired during prehistory, the flow of clues isn’t one way. The past may very well be the key to the future, especially when we want a preview of what can happen during periods of rapid climate change (like the human-caused one we’re in now). The latest study in this emerging area of research centers on the fate of ancient mammals that went through