jan 1, 59000000 BC - Mammals are diverse and common: 59 mya
-the early true mammals were mainly small insect-eating creatures adapted to nighttime activity. They ranged in size from scarcely bigger than a bumblebee to squirrel-sized, keeping out of the way of the predatory dinosaurs
-End of period were dos, cats, and pigs.
-They acquired certain traits that would characterize mammals ever afterward: limbs positioned under the body, an enlarged brain, a more complex physiology,
-It took several million years for the mammals to evolve even moderately large body sizes,
Added to timeline:
Global Time Scale