That's Not a Hippopotamus! - Juliette MacIver

A deft and delightful tale, packed with word play and madcap energyA class trip to the zoo descends into a chaotic hunt for the missing hippopotamus. Teacher, zookeeper and all the children join the search. The noise and drama reach a pitch, and no one thinks to listen to quiet Liam, who really might know where the hippo is hiding.