The rats in The Amazing Maurice and his Educated Rodents are sentient, and capable of talking. This is due to eating magical refuse from the dump behind Unseen University. They named themselves from the labels on the rubbish, before learning what the words meant. Additives was eaten by Maurice, and since eating something containing magical refuse has the same effect as the garbage itself, Maurice can now talk. Unfortunately for him, he can remember Additives begging not to be eaten. This is what keeps Maurice so vigilant in asking potential morsels to 'say anything at all other than squeak' before he eats them.