This is a very good book for any child whether interested in dinosaurs, bison, wolves, bears etc. or not. The book starts in Yellowstone National Park during the late cretaceous period and takes you on a journey through the changes of the park and it's inhabitants. The author has included a wide variety of mammals along with a short bio including it's name, height, length, weight and whether they are an omnivore, carnivore or herbivore. I love the story and the illustrations and think the author did a wonderful job. It not only tells a story but also is very informative. ( )