Like people, animals go through a phase when they lose their baby teeth and grow new, adult teeth. Kittens go through this phase once when they're around three weeks old and their milk teeth come in, and then again at a couple months of age when they lose their milk teeth and grow adult teeth. Though painful, this is an important aspect of growing up and moving on to adult food. All kittens display some general signs of teething.
During teething, new teeth actually break through the gums. Any kitten going through the process begins to chew as an attempt to relieve this pain. Kittens generally chew on wood, furniture, bedding and the hands of their owners. This is a natural response to teething and should be redirected rather than punished. Give kittens designated teething toys like straws, toys and cat furniture to keep the kittens from chewing on valuable items.
Kittens have sore, swollen gums when they're teething. Their gums become a darker pink than normal, and appear swollen and puffy. If owners rub their fingers along the gums they will feel the sharp tips of the new teeth poking through. Sore gums cause many kittens to stop eating, as chewing becomes painful. Feed kittens wet food at this time to maintain their level of nutrition until they can start on crunchy food again.
Teething kittens start to "complain" to their owners about their discomfort. These complaints may be vocal, with loud yowls, or physical, as kittens become clingy and needy. Kittens may also pout or become listless and sleep for long periods of time, depending on their personalities.
Some kittens begin to exhibit a behaviour that is akin to nursing, where they suck on the fingers or clothing of their owners. Although this behaviour may appear at the same time as teething, it is a symptom of a kitten that was taken from its mother at a young age, rather than teething. This behaviour should not be taken as a symptom of teething or pain, but a habit that will probably last for the cat's entire life.