When I think of mammals from the Age of Dinosaurs, I think of a shrew-like critter snuffling through the nighttime undergrowth. I can’t help it. That’s the meme that museums, books, and documentaries popularized when I was a fossil-crazed kid.

The classic view of the meek mammal eking out a living in a world dominated by dinosaurs is too simplistic, though. Mesozoic mammals are undergoing a renaissance – much like their saurian oppressors got in the 1970s – and have turned out to be far more varied than anyone expected. Mammals of the Triassic, Jurassic, and Cretaceous were small, to be sure, but they counted swimmers, climbers, diggers, gliders, and more in their fuzzy family. They didn’t just live