One big happy family — or not?

In the movie “Ghostbusters,” Bill Murray put it in the same category as human sacrifice, fire and brimstone raining from the skies and zombies emerging from their graves.

What could be so calamitous?

Dogs and cats living together, of course.

After all, don’t we talk about people fighting “like cats and dogs”?

But it doesn’t have to be that way. In fact, most dogs and cats can get along just fine. That being said, there are some breeds with a genetically high prey drive that tend to see a running and darting kitten or cat as prey. (Notice I said “tend”— there are doubtless hundreds of exceptions. The key is to do a dispassionate evaluation of your particular dog to make sure he’s not disposed to seeing Fluffy as a predatory target.)

Whether you’re adding a new cat to your dog household or a new dog to your cat domain, the introduction sets the tone for the relationship. Even if your dog’s temperament could be compared to the Dali Lama and your cat to Mother Teresa, don’t just throw them together in a room and walk off. Unexpected personality quirks can arise without warning, one or the other animal can become frightened or aggressive, and you can end up with serious problems. Remember, it’s always the cat that’s at greatest risk, so let her decide when and how she’s going to approach the dog.

If you have a dog and you’re bringing home a new kitten, remember that often kittens have little fear, so watch the interaction closely and never leave them alone, since even a cat-friendly dog can accidentally injure a kitten by playing too roughly.

Kittens and puppies generally have little problems in getting along, but a kitten can easily be hurt by a rambunctious pup. Introducing a new puppy to your adult cat is less problematic, as most adult cats will let the puppy know with one swipe of a clawsbared paw if the dog isn’t being respectful of their feline space.

Many experts recommend confining one pet to a separate room at first, preferably behind a babyor pet-gate; that enables each one to become accustomed to the new pet’s presence and scent without putting either in danger.

If that goes successfully, you can allow both animals in the same room, but make sure the cat has an escape route. It’s not a bad idea to keep your dog leashed during this time. A positive sign is when the dog is calm and pretty much ignoring the cat, and the cat is also unruffled.

Once you see your cat playfully batting at your dog (without claws!) or rubbing against him, or you see your dog gently nudging or licking the cat, you can rest assured that the two have pretty much worked out their differences. After three or four weeks with no problems, you should be safe in leaving the two alone together.

Now comes the warning: watch for these danger signs during the introductory process:

• The dog is overly focused on the cat or lunges toward it whenever she moves.

• The dog shows signs of direct aggression toward the cat such as snarling or snapping.

• The cat is constantly growling, swatting and hissing at the dog.

These sorts of behaviors could signal that this particular feline-canine match isn’t going to work, or that you need to consult a behavioral specialist. In the worst case, you may have to accept that yours will be a one-species household. The good news is that most dogs and cats can learn to coexist and often become fast friends.

Joan Merriam lives in Nevada County with her golden retriever Joey, her Maine coon cat Indy and the abiding spirit of her beloved golden retriever Casey in whose memory this column is named. You can reach Joan at joan@ joanmerriam.com. And if you’re looking for a golden, be sure to check out Homeward Bound Golden Retriever Rescue.