Story of Doctor Dolittle

Dr Dolittle lives in Puddleby-on-the-Marsh with his friends Dab-Dab the duck, Jip the dog, Gub-Gub the baby pig, Too-Too the owl, the parrot Polynesia, as well as rabbits in the pantry, white mice in the piano and a crocodile in the fish pond. Why do the animals love Dolittle so?