Domestic cats are not much different from their wild cousins in their behavior. Female cats are defensive in their natural maternal instincts. Male cats are natural hunters and more aggressive toward things outside of their own comfort zones. In each case, their teeth and claws are their natural defensive tools.
Male cats have a tendency to be more aggressive toward strange animals and people. Male cats also exhibit scratching and biting as playing exercises. This type of play reinforces their hunting instincts in the wild.
Instructions
Neuter your cat. Aggression is a hormonal thing in animals. Neutering is not only important to control an exponentially growing population of feral cats, but it also decreases the impulse for male cats to attack others.
Get your cat its rabies shots because this and other diseases may cause it to bite. Overly aggressive cat behavior could be due to physical ailments, so bring the cat to the veterinarian if the biting is vicious and persistent.
Get a second cat as a play mate. Another cat is often a distraction from attacking others. Two cats focus their attention on each other. Two males often will fight playfully, but rarely to hurt the other cat. If your cat become overly aggressive to the new cat (to the point of physically hurting it), contact your veterinarian.
Take your kitten to the groomer, the veterinarian and the cat sitter early in life. Cats learn to socialize as kittens. An older cat who experiences a stranger for the first time is more likely to feel threatened.
Do not let strangers make sudden gestures towards the cat. Cats often will bite and scratch to protect themselves. The sounds the cat makes and its body language may indicate to you that it will strike in defense. Strangers often will reach out to pet a cat who thinks it is being attacked by the sudden movement. Cats naturally avoid confrontation and easily feel threatened by sudden moves in their direction. Let the stranger know that the cat may be aggressive or defensive and pet the cat yourself until it becomes accustomed to the smell of the stranger.
Play with the cat when it attempts to bite or scratch you. It is important to work on getting your cat's trust and confidence before introducing it to strangers. Reward the cat when it behaves correctly, such as when it scratches on a scratching post or chews on a cat toy. Instruct your neighbors to play with the cat. Cats need to play. Hand a cat toy to your neighbor when he visits. But the more you play with the cat yourself, the more it recognizes humans as play mates and may be inclined to be playful with strangers.
Allow your cat to approach strangers on its own terms. If the cat is not sociable, do not let strangers approach him. When the cat is hungry, let the stranger hold out cat treats. It might take time before the visitor can get closer to the cat with the treat in hand.
Do not let the stranger allow the cat to play with his hands. This will teach the cat to play with hands. That means biting them.
Have the person push gently towards the cat and make noise if the cat bites his hand. This will confuse the cat and he will let go of the hand.