There is a long and storied history of nonhuman actors, from Luke, the dog of silent star Roscoe "Fatty" Arbuckle, to the collies cast in the role of Lassie in film and on television. Bart the Bear ...

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) But business has not been as good as it used to be for the animal trainers who ...