Simon Thorn and the Wolf's Den by Aimee Carter
Twelve-year-old Simon Thorn's life has never been easy, but being bullied at school and living in a cramped Manhattan apartment with his Uncle Darrell is nothing compared to his biggest secret: he can talk to animals. When his mum is kidnapped by a herd of terrifying rats, Simon finds out that he, his mum and his uncle are all Animalgams - people who can change into an animal at will. In search of his mother he discovers the Animalgam Academy located underneath Central Park Zoo. There he learns about the fractured five kingdoms that make up this secret world - Mammals, Birds, Insects, Reptiles and Underwater. And Simon Thorn is the only one who can save them. Imaginative and vivid with themes of bravery, loyalty, and finding one's true self, this exciting, five-book adventure series is perfect for fans of Rick Riordan's Percy Jackson and Beast Quest.