This title examines the insects, mammals, and sea creatures that eat blood, the diseases those animals can spread through their eating habits, and the ways doctors have studied and used these animals to advance medicine. This book also includes a table of contents, fun facts, an Animal Spotlight special feature, quiz questions, a glossary, additional resources, and an index. This Focus Readers title is at the Beacon level, aligned to reading levels of grades 2-3 and interest levels of grades 3-5.