I nearly have a prompt that I want to submit but part of it hinges on an animal that could be present in a prison. I'm essentially looking at an animal that could double as a guard dog. There are too many animals to consider in the universe and I'm totally at a loss.

To help with the context, beyond guard dog for hire, I'm looking for an animal that would give birth comfortably indoors - or close to a prison, and would have a litter that could include a "runt of the litter." And enjoy being around humans/humanoids, since the runt will be coming across one of the prisoners.

Any help would be appreciated.