Scientist Jackson Oz has discovered that all around the world, animals have started attacking humans. Jackson and fellow scientist Chloe set out to warn scientists and politicians about the attacks, before it is too late. Penguin Readers is a series of popular classics, exciting contemporary fiction, and thought-provoking non-fiction, written for learners of English as a foreign language. The series is aligned to the Common European Framework and includes language activities that help develop key skills. Zoo, a Level 3 Reader, is A2 in the CEFR framework. The text is made up of sentences with up to three clauses, introducing first conditional, past continuous and present perfect simple for general experience. It is well supported by illustrations, which appear on most pages.