Cambridge Discovery Education Interactive Readers are the next generation of graded readers - captivating topics, high-impact video, and interactive exercises designed to motivate and engage. Penguins that exchange wedding rings? A fish that doesn't swim? Learn all about the bizarre and unexpected behavior of animals from around the world. Use the unique code inside the book to access the online reader, complete with videos and interactive exercises. Word count: 1993. Lexile Reading Level: 720L.