Introducing Your Dog to a New Animal
In most situations, introducing your dog to another animal such as a cat or dog can be fairly simple if done while each is still young. If you have adult pets, the interaction can be more intimidating for the animals, just from the fear of the unknown.
Most of the time, you would want to introduce your dog to another dog on neutral grounds. Having them meet at a park on leashes is an excellent way to do an introduction. Having an extremely dominant dog introduced to another dominant dog in one of their backyards would be the least perfect place to get to know each other. Having the dogs on leashes will allow you to control the animals efficiently and prevent situations from escalating. Always do the intro in moderation and slowly expose them to each other for longer periods and eventually, off the leashes leaving a safe place for each of the dogs to go to.
Introducing your dog to a new kitten or cat can be very hard, especially if your dog is an adult and has been pre-exposed to stray cats or others that are not around on a consistent basis. You want the cat to enter the house freely without the dog being around to consume their space. There may not be a pleasant reaction between the two, so keeping your dog on a leash and the cat at a distance will ensure the safety of both animals. Never leave the animals alone together, and slowly increase their times spent together, giving your dog stern hard commands, so they understand that the cat is not their enemy.
Introducing your dog to a new animal can be stressful, but remember to stay as calm as possible because animals do read off your energy and can pick up on nervous behaviors, causing them to become anxious themselves.