The entire Cenozoic history of the world is often laid out something like this: dinosaurs were in charge until 66 million years ago, when a wayward asteroid decided otherwise, and then mammals breathed a sigh of relief as they took over. About 60 million years after that the first humans swung down from the trees, and no one has been able to argue with absolute certainty whether this has been a good or bad thing.

Of course there’s far more to the story. The “Age of Mammals” doesn’t get the respect it deserves these days.

Even though the entirely of the Cenozoic is short compared to other eras – 66 million years can fit comfortably between dinosaur superstars Tyrannosaurus and