"“It is a nice household,” he murmured. “That is the baboon.”..."
See in text (The Adventure of the Speckled Band)
The pet baboon and cheetah are odd touches in this story. It is likely that Doyle employs the beasts metaphorically and metonymically to suggest the wildness and beastliness of their owner. It is also possible that these animals offer a justification for the presence of the exotic serpent.