We don’t often think about it, but the pets we keep are either natural-born predators or prey. Mice, fish, rabbits and certain reptiles, for example, are hardwired with the instincts of a prey animal, ready to move quickly and escape when circumstances warrant. As Gina Spadafori — author of Cats for Dummies — points out, however, cats are both predators and prey, depending on the circumstances.

When animals first meet, they usually note each other’s size, the information contained in smells, the intentions revealed by multiple signals and more. A big, strong cat might then feel it has a chance at competing with a small, timid dog. But little dogs can be temperamental, and canines in general tend to be much larger than cats. Some dogs are also bred to hunt, so both genetic hardwiring and in-the-moment information will likely cause a cat to run.

Spadafori does note that “many people live in homes with all kinds of pets coexisting quite peaceably.” Experience then comes into play. A particularly challenging situation is when you have an older cat and bring in a new dog. She advises that you keep your dog on a leash during the first introductions, until you can be certain that the animals are getting along. Your cat’s food dishes, litter box and sleeping areas should all be in secure, dog-free zones. Your cat might have to be sequestered in a well-equipped room until it acclimates to the new roommate.

Cats and dogs that have been raised together, however, often play and snooze with each other. In those peaceful situations, predator and prey labels become irrelevant. The pets are all family.