Adults are still curious and love to explore, but now they will sit down and be still for longer periods of time.

Motherhood

Mothers and her kittens are inseparable.  They depend on her to take care of them.  Kittens' senses do develop quickly, but kittens need their mother's milk to stimulate body functions.  

When cats become older, their behavior and mood changes.  Your cat may become grumpy and annoyed, or more affectionate and loving.  Your cat will slow down, sleep more, and may have a different appetite.  Some cats gain weight from the lack of exercise, while others loose weight from not eating as much.  

As well as those differences, your cat's hearing and/or eyesight might begin to fail.  You will probably have to groom, your cat more often because they find grooming difficult.