Some basic types of cat body language include slow blinks to signal trust, a relaxed upright tail to signal confidence, and an arched back and puffed-up tail to signal fright. An anxious cat puts its tail down between its legs and pulls its ears back.
Some signals of irritation and aggressiveness in a cat include dilated pupils, a twitching tail and turned-back ears. Signals of contentedness in a cat include half-closed eyes, narrow pupils, a still tail and forward-turned ears.
Cats typically communicate with each other using body language instead of vocalizations. Many cats only meow at their human companions, not at other cats. A cat uses its body, tail, ears and eyes for communication.