While dinosaurs bested their early crocodile competitors, sailed through the end-Triassic extinction, and then grew to colossal sizes and spread throughout the land, mammals remained in the shadows. They became adept at surviving in anonymity, learning how to eat different foods, hide in burrows, and move around undetected, some even figuring out how to glide through the canopy and others how to swim. All the while, they remained small. No mammal living with dinosaurs got bigger than a badger. They were bit players in the Mesozoic drama.
