Pets are supposed to be a joy to keep and, in many instances, that's exactly the way it is. But though they may dote on you, two or more pets may not get on well together.
Aggression between pets is one of the more common undesirable behavior problems facing pet owners in multi-animal households. Cat to cat, dog to dog, or dog to cat, aggression within and between species can make living with the feuding parties a veritable nightmare.
Let's deal with the problems separately.Feuding Between Cats
Intercat aggression is one of the most common feline behavior problems. Cats fight with other cats for a variety of reasons, not least of which relates to differences in their personalities and agendas. Like dogs and humans, cats don't get along together simply because they belong to the same species; they often have strong individual likes and dislikes and minds of their own. You could say they're fussy.
The best recipe for peaceful cohabitation is to have related cats that have been raised together. The second best situation is to have unrelated cats get to know each other from an early age so that they can develop time-sharing arrangements and other mutual understandings. Combining unfamiliar adult cats is a crapshoot but sometimes things work out quite well. The worst case scenario is for an early-weaned loner cat that has been raised with a doting single owner to suddenly find herself with an unwelcome roommate. Such cats are not good mixers and often prefer to be only cats.
Problems related to individual cat personality differences can be assessed:
a) with reference to the past experience and known sociability of the cats, and
b) by observing the cats' attitudes toward each other when they are first introduced.
A small amount of hissing is not a good sign but may settle down in time, typically over about 4 months. Major meltdowns should probably cause you to rethink the wisdom of the mix.
Aggression may escalate in unfriendly cats, with one becoming the aggressor and the other the more passive aggressive or simply terrified victim. This situation, fueled by dominance on the part of the aggressor, is termed territorial aggression and is one of the hardest behavior problems to resolve. It's probably better not to go that route.
Occasionally, aggression suddenly explodes between two previously friendly cats. The motivation in such instances can be either:
a) redirected aggression
b) fear aggression or
c) non-recognition aggression.
Redirected aggression occurs when one cat sees something that gets her excited, but that she can't reach (usually because a window separates her from the object). Instead, the angry cat redirects her wrath at a nearby feline companion, an innocent bystander. The motivation behind this type of aggression is analogous to an angry man punching the wall or kicking his dog. Of course, the victim of the sudden onslaught does not understand the motivation for the attack and may retaliate. A slightly different version of this type of aggression occurs when one cat flies at an outside cat in a state of high arousal and scares its buddy. Each inside cat can misinterprets the other's body language and intentions, sometimes with cataclysmic results and thus a permanent deterioration in the formerly happy relationship. The way to avoid permanent, irreparable problems is to separate the cats behind closed doors for as long as it takes for them to settle down. This can be hours or days. Separation of feuding cats prevents them adding insult to injury and building up grounds for long lasting animosity.
Non-recognition aggression is not dissimilar. It occurs when one cat is returned from the veterinarian's office and acts or smells differently. Presumably it occurs as a result of failure of recognition of the returning cat as the at-home cat becomes incensed with its roommate as she hops (or staggers) from the carrier. Serious battles can result, particularly when the remaining cat is of non-equable disposition (i.e. flies off the handle easily). Treatment is as before: Separation and gradual reintroduction. Feuding Dogs and Cats
The expression "fighting like cat and dog" arose for good reason. The two species are fundamentally quite different and will often view each other with animosity unless steps are taken to engineer a positive perception. Though both species are highly territorial and predatory, dogs are larger and will chase cats off or even kill them under certain circumstances. Dogs that have not been socialized toward cats from an early age are not likely to be friendly toward cats that coexist under the same roof, and vice-versa. The best that can be hoped in such cases is aloofness, mutual avoidance, or a brittle peace maintained through avoidance and/or hostile gestures.
The sensitive period of learning regarding social acceptability is between 3 and 12 weeks of age in dogs and between 2 and 7 weeks of age in cats. During this time a plethora of unlikely liaisons can be engineered using appropriate ploys. During the sensitive period it is possible to arrange seemingly impossible feats like lions being made to lie down with lambs. However, it is often not possible to raise kittens with puppies
to create such "bon accord au naturelle." But a huge step in the right direction involves introducing puppies and kittens to friendly members of the opposite species during this window of time.
If you are unlucky enough to own a dog and cat in which neither animal has been raised in this way, you may have an ongoing battle on your hands (as the Clinton's did with his pets in the White House). One solution is to find another home for one or other animal, but if you have time and patience, you can sometimes make the best out of a bad deal through appropriate retraining. You can teach old dogs and old cats new tricks –it just takes a little longer. The plan would be to introduce the feuding pair to each other at a distance, or across closed doors, with each animal (especially the dog) under good control. When each animal is calm and relaxed, this state of affairs is handsomely rewarded. If this procedure is repeated frequently, each pet learns that, in the presence of the other one, good things happen. The distance between the two pets should then be incrementally decreased, and the time they spend together increased, until the two can coexist together.
Managing such a reintroduction program takes strong leadership on the owner's part, plus patience and good physical control. The feuding parties may never become the best of friends but some odd couples can at least be taught to tolerate each other's presence. Just in case your newly trained animals suffer at setback, it is prudent to provide a place to which your cat can retreat, should the need arise A climbing frame, a springboard to a tall piece of furniture or a narrowly open, firmly secured, cupboard door will provide safe harbor for the cat in times of emergency or exasperation. Sometimes, it is the dog that is on the receiving end, though, in such instances, the dog usually learns to give the cat a wide berth, thus circumventing trouble. For peace of mind, be advised that cats don't kill dogs and the worst injury that the dog is likely to experience is a scratched cornea. Soft Paws® (plastic nail caps) or simply regular nail trims (plus nail filing) for your cat will help reduce this unwelcome complication.