In the aftermath of the dinosaur-killing asteroid impact, a tiny mammal species emerged around 65 million years ago. This newly identified species, weighing around 1 pound and the size of a chinchilla, provides valuable insights into the evolution of mammals after the Cretaceous-Paleogene (K-Pg) mass extinction event. Its discovery helps scientists understand the diversification of mammals into different forms that led to modern hoofed mammals like cows and horses.