Do you want your cats and dogs together? If your pets are older when being introduced for the first time, then you will have to work harder than if your pets are kittens and puppies. This is because they are already used to their routine and change = stress.
It is not impossible to get them to live in harmony. Even if your dog and cat do not become best friends, they can learn to tolerate each other and respect their spaces. The idea is to change the way they feel about each other, which can be done by rewarding positive interactions between your feline and canine friends.
Using food, respecting their personal spaces and having a lot of patients are key factors for success. Keep in mind that older pets, just like older humans, take longer to change habits. Also, yelling or getting mad at one or both of them will not help AT ALL, it will only make them feel more stressed and the situation will worsen.
Do you have kittens and puppies? The program is slightly different so click for information.
Does your dog like to chase everything that moves? Is the cat shy and likely to always run away from the canine? This will certainly create a chase game that will end bad. Similarly if a dog is used to playing rough. It would be unwise to get a kitten or elderly cat.
Matching dogs and cats personalities can be a hard thing to do, specially if you do not have many choices. If you DO have choices, then I highly recommend you plan this ahead of time.
This is a lot like socializing dogs and cats. If your pet has never encountered the opposite species, you need to introduce your pet to several animals and associate this introductions with positive things (like treats, toys, attention and games) before you bring a new family member home.
Food treats must be SUPER good!
I recommend dried fish treats because both species will like it, and cats will go crazy about them (you need them motivated).
When going out for walks pay careful attention how your furry friend reacts to cats. Does he bark and lounge? Does he ignore the cat? Is he mildly curious?
NOTE: if you do not have friends with dog-friendly cats, ask the shelter you will adopt your cat from. If you can't find any cats to socialize your dog, you can move on to the next step but will need to do the introduction very slowly and with special caution.
Cats are often indoor pets and territorial animals. Do not attempt to take your cat to the shelter or other people's homes to meet a dog. This will stress the animal enormously and set you back instead.
Bring the new dog to the house and proceed with caution and very slowly as explained in the following steps.
Find a safe place for each animals. Cats often like high places. A cat tree or high shelf are good ideas. For your dog you can use a crate.
Cat trees can be found at Amazon in all shapes and sizes. A cat tree or high perch is a must because your cat should be able to escape easily if needed.
In the beginning you will let each animal investigate the other pets safe place while it is empty (unless it's high and the dog can't reach). Do not punish the animal for getting near these areas. Instead reward them when they stay away from it! For example, reward your cat for staying in his area. When the feline ventures into the canine area, gently remove him and show him the way to his own place, then immediately reward this!
Cats are often more territorial than dogs, that is why a safe place for the feline is very important. Also, because cats like heights it is easier to keep the dog away. Make sure the cat can get down from its high place comfortably though, without a furry canine always waiting at the bottom.
The first time you put your cats and dogs together, they should be gently restrained. You can use a dog and a cat leash or have both animals in different crates (with open bars so they can see each other).
This step requires patience and depending on the pair it will go faster or slower.
The idea is to help the dogs and cats create a positive association about the other. This goes back to Classical Conditioning. You need to teach the animals that when the cat (or dog) is present, only good things happen (treats, toys, games, attention).
Have special toys and treats that ONLY appear during these introduction times. This will ensure that the reward is powerful and special.
Finally get your cats and dogs together!
Put the cats and dogs together in the same room, gently restrained like I mentioned before. In the beginning you might only be able to reward them just for being in the same room. This means, they will get treats even if they look stressed. Do this until they start looking forward to these meetings (because they get good rewards!).
Then, as they settle, continue rewarding them but ONLY if they remain calm and interact properly. No signs of aggression or stress. Depending on how your pets react to each other you might need to do many short sessions throughout the day for several days. You will know when they are ready for the next step when you put them in the same room with gentle restrain and they behave calmly towards each other.
If your canine friend is constantly staring at the cat, try to distract him away. When he pays attention to you (and not the cat) give him a treat. Repeat many times until your dog starts ignoring the cat on his own. If the dog can't ignore the cat and only stares and lunges whenever the cat moves (or even if the cat is still) you might want to reconsider. This canine is not good to be around cats. The opposite is also true (cat that attacks the dog constantly).
When you leave the house, make sure dogs and cats are confined to different rooms.
Keep the dog on the leash for this step, but let the cat walk around the room without any type of restrain. Again, always reward good interactions.
Repeat this introduction until the dog does not react to the cat at all and they both seem comfortable around each other (they can eat, lay down, use a litter box).
If any of the animals react too strongly, go back to step four. This is not a setback, it will help the animals learn better.
Again, if you leave the house keep dogs and cats in different rooms.
When your dog no longer reacts to the cat, it is time to introduce them without any restrain. But always make sure the cat has a place to escape to, like a high cat tree or shelf. The first few months you will want to supervise these types of cat-dog interactions.
Note: if the cat stops using the litter box (soils other house areas), stops eating or stops interacting with the members of the family, the cat is too stressed. You need to go back to previous steps or re-think keeping both pets.
Only after you are absolutely confident the cats and dogs are together safely, you can live them unsupervised.
You are done, your cats and dogs together at last, they are getting along! Congratulations!
Consider consulting with a trainer or animal behaviorist for help. I tried to give you a detailed explanation with clear steps to follow but sometimes the keen eye of a professional can help you move along faster and without much stress.