Toto is a fictional dog in L. Frank Baum's Oz series of children's books, and works derived from them. He was originally a small terrier drawn by W. W. Denslow for the first edition of The Wonderful Wizard of Oz (1900). He reappears in numerous adaptations, such as The Wizard of Oz (1939) and The Wiz (1978). Toto belongs to Dorothy Gale, the heroine of the first and many subsequent books. In the first book, he never spoke, although other animals, native to Oz, did. In subsequent books, other animals gained the ability to speak upon reaching Oz or similar lands, but he remained speechless.

Source: Wikipedia