Some cat behavior is more immediately obvious, for example an inside cat being upset over seeing a cat in his yard. However, there are situations such as a sudden change from purring to biting that are perplexing to say the least. All aggression whether seemingly misdirected or redirected, is as a result of a perceived threat. When we get kitties from the shelter/pound, we don't always know their history. This can pose a challenge because in some cases, if the cat was hurt or otherwise threatened as a kitten, he may have learned that reacting in an aggressive manner would end the harassment. Even though he is now in a loving home, he might still react based on fear as that is instinctive to him.
Why do cats scratch?
Scratching is not only pleasurable, it is also necessary for cats as it helps shed old layers from their claws to expose new sharper ones. When cats are outside, they scratch trees and stretch while they are doing so. Scratching is just as enjoyable an activity for indoor cats, and as it conditions their claws, scratching is beneficial for them. In addition, when cats scratch they leave behind their scent in that area. This is another form of marking behavior that is very natural to a cat.
If your cat is good about using the litter box and suddenly stops using it, this can be a signal of an underlying medical problem like FLUTD that needs to be addressed immediately. When the core problem is dealt with, the aberrant behavior usually goes away. In this article, we'll assume that physical problems have been ruled out by your veterinarian, and the problem is behavioral in nature.