Meet six friendly hippos in this exciting addition to the much-loved That's not my... series. Babies love these best-selling books with their bold illustrations, textures to explore, and a mouse to spot on every page. - That's not my... books are designed to be shared, and support sensory and language development. - Don't forget to spot the little white mouse on every page! - DID YOU KNOW...? One That's not my... book is sold every minute in the UK! - With over 80 titles to choose from, there's a That's not my... book for everyone.