I'm so glad you asked!

When cheeky ol' Chicxy the giant space rock decided it was time to take a bath off of the Yucatan peninsula. Thus, once again becoming squeaky clean...and incidentally wiping out 75% of all life on Earth in the process. Effectively erasing all non-avian dinosaurs...Whoopsies! Little did we know there was a third order of Dinosaur that survived alongside those that would become our modern-day birds. The Minimischia or "tiny-hipped" dinosaurs. Due to their size they managed to survive much in the same way our mammalian ancestors did. They have since remained largely unchanged in appearance and are near perfect copies of their larger cousins. Save for the miniscule size and variations in pigmentation.