Book excerpt: Scientists have long debated the relationship between birds and reptiles. After all, there are some physical similarities between the species, from the eggs they both lay to the scales that can be found on their bodies. But what about the differences? Birds have feathers and are warm-blooded. Reptiles slither, crawl, and creep and are cold-blooded. Scientists study these similarities and differences by observing and experimenting, and now you can too. Whether you try the experiments and activities in this book for fun or for a science fair project, you’ll get an up-close and personal view of these two incredible types of animals. Are they related? You be the judge!