In the battle between cats and dogs, dogs are usually depicted as the instigators. But sometimes, it's the cat who has it in for the family dog. Though it's certainly possible, and actually quite common, for cats and dogs to get along and even form friendships, some cats just want nothing to do with dogs. They may even turn hostile toward the friendliest and gentlest of pups, leaving you to wondering what to do.
This can be especially true of a shelter cat introduced into your home. Although shelter personnel should be able to tell you whether a cat gets along with dogs, sometimes cats are on their best behavior at the shelter and only show their true temperaments after they've spent some time in a home. It's also impossible to determine an adult shelter cat's background, so there might be something in their past that triggers an intense dislike of dogs. But your home doesn't have to be a battleground for pets. With enough time and patience, you can teach your kitty to peacefully coexist with your pup.

Understanding Types Aggression in Cats
There are several reasons why your cat may be acting out. Understanding these underlying causes of a cat's aggressive behavior can help you identify triggers and put a stop to your pet's hostile antics, explains cat behavior expert, Pam Johnson-Bennett.
Fear Aggression
A fearful cat may react to your dog by trying to get away. If they feel trapped, they may try to make themself appear smaller by crouching, flattening their ears and wrapping their tail tightly around their body. If your pup doesn't take the hint to back off, your kitty will eventually lash out in what they perceive as self-defense.
Redirected Aggression
If your cat sees or hears something they want to attack but can't get to, such as another kitty outside the window, they may turn around and take out their pent-up aggression on the nearest target instead — in this case, your unwitting dog. Acts of redirected aggression can feel random because you aren't aware of what triggered them. It seems like your cat just decided to beat up on your poor pooch. But in reality, your dog is simply a convenient target — in the wrong place at the wrong time.
Territorial Aggression
A new cat joining your home may feel the need to quickly establish their territory and assert their dominance over the other household pets. In this case, any attacks they make on your dog are simply an attempt to establish boundaries and show your pup who's boss. If your dog is submissive and doesn't fight back, your kitty will only feel more encouraged to exhibit bullying behavior. The gentler a dog, the more likely they are to become a target for your cat's aggression.
Aggression Due to Overstimulation
If you've ever suffered the consequences of petting or playing with a cat beyond their tolerance threshold, you know how fast they can go from purring and playing to scratching and biting. Dogs may seal the same painful fate for themselves if they overstimulate a kitty.
Predatory Aggression
Stalking, pouncing, chasing and lying in wait for an ambush are all part of a cat's innate predatory instincts. Though birds, mice and other small animals are typically their targets, your kitty may take out their predatory behavior on other members of the family, including your dog, if actual prey is not available. If this is happening, it's a good indication that your cat isn't getting enough mental and physical stimulation and exercise; i.e., they're acting out because they're bored.

Unprovoked Aggression
Unprovoked aggression, attacking or lashing out without cause, is extremely rare for cats. Often, what appears to be unprovoked aggression is actually redirected aggression. However, there might be another cause for this behavior, such as your kitty experiencing pain or the effects of an underlying health condition. If your cat seems to be attacking your dog or another member of your household for no reason, consider taking them to the veterinarian to rule out any medical causes that might be in play.