Long ago, about 36 million years before today, a raft of monkeys found themselves adrift in the Atlantic. They’d been blown out to sea by an intense storm that had ripped up the African coast, and now a mat of floating vegetation was the closest thing to land for miles in all directions. But luck was with them. Thanks to a favorable current, they were thrown onto the beach of a new continent – South America.

I’ll admit that this scenario requires a little scientifically-informed imagination. No one has ever found a fossilized huddle of monkeys clinging to battered vegetation in ancient ocean sediments. But we know that such events must have happened in the past. Teeth tell the tale.

In the