How do animals work together to survive? What kinds of relationships do different species have with one another? Read this book to find out! Readers will travel around the world to meet barnacles on whales, teethcleaning fish, and parasitic ticks. Students will learn about the many ways animals work for and against each other through symbiotic and parasitic relationships. Stunning photography introduces individual animals, and a handy glossary helps to expand readers' vocabulary. For more information on the daily lives of animals, check out other titles in the Animals at Work series!