Cats can’t speak because if they could, they’d likely bark out an endless number of orders, commanding their humans to submit to their will. Of course, cats can express their emotions anyway and a┬áveterinarian at the University of Pennsylvania Veterinary School believes he has identified six ways cats communicate using their tails.

A stretched tail denotes aggressiveness. A tail stretched with a hook up is usually a greeting. However, a tail stretched with a hook facing down is a defensive attitude. Unfortunately, this veterinarian neglected to determine what it means when your cat slaps you in the face with its tail.

To read how to interpret your cat’s emotions by looking at its tail, click here.