Excerpt from Starting from Scratch by Pam Johnson-Bennett
Your cat may be a mild biter during play or she may be one who means business when she chomps down, inflicting pain and drawing blood. In either case, biting behavior must be corrected.
First, figure out the trigger. Does she bite your hand when you're playing with her? One of the most common mistakes people make is to use their fingers as toys to entice cats to play. This may have seemed harmless enough when your cat was a kitten, but as she grew and developed adult teeth, those bites probably started to hurt more. Unfortunately, if you used your fingers as toys, you sent a message to her that biting flesh was acceptable. In her mind, if biting flesh is okay during play, then it's also okay for her to bite when she needs to communicate other things as well. Some cats bite to solicit playtime. From previous experience, they learned that biting gets a response from the cat owners and a toy is tossed for them. Unfortunately, that just reinforces the biting behavior. In this way, she has trained you.
If you use your fingers as toys, even if protected under a blanket or other fabric, it's time to stop. No more mixed messages are to be sent to your cat. From now on, all playtime that involves you should be done with an interactive toy. The typical fishing pole-type toy puts a safe distance between your fingers and your cat's teeth. Don't even use a small toy when playing with her. Little fuzzy mice and other small toys are meant for her solo play. Even if you've never used your fingers as toys, if you've tried to hold a small solo toy for interactive play, your cat may have bitten your accidentally because she couldn't distinguish where the toy ended and your fingers began. Her prey-drive was in gear and she was focused on capturing her prey, and that experience during playtime should be set up so that you don't have to worry about where your fingers are.
Your cat may bite moving hands or feet because that' the only stimulation she receives that satisfies her desire to play. If there are no other outlets for her, it's not surprising that she's resorted to biting anything that moves, even if it's your bare feet.
Your biting cat may also be communicating that she wants you to stop doing something. A bite to the hand that's been stroking her often gets you to stop doing what you're doing. She may have been giving other signals to let you know she was not longer enjoying the interaction, but if you missed them, she may have felt her only option was to bite.
Biting may have become a very effective means of communication for your cat. She may bite you when she wants to take your spot on the couch or to be fed, let outside, given attention, left alone, and so forth.
Don't use any physical reprimands when trying to get your cat to stop biting. Hitting your cat will only confuse her, and if she bit you as a defensive raction, that'll only heighten her feeling of being threatened.
To learn more about modifying unwanted cat behavior, purchase Starting from Scratch from Catnip.