Although cats have a reputation for being independent, there are times and situations when they can (and do) interact with others of their own kind and humans in a social way. When motivated, they make their needs and wishes known to others without the benefit of speech or language as we know it. Cats have subtle ways of communicating, some of which have eluded scientific scrutiny for years. The senses and behaviors cats use to facilitate communication include vision/eye position, olfaction, touch, voice, body language, and operant actions.
A blind cat is at a serious disadvantage when it comes to communication because so many signals sent and received by cats are visual. On the aggressive end of ocular signaling is the stare. An irate cat will transfix her adversary with a blood-curdling look of animosity and malicious intent. If you've even been the subject of one of these looks, you'll know what I'm talking about. The corollary to the stare is the fluttering blink of trust and affection. If a cat doesn't trust another creature, she will keep her eyes wide open. Semi-closed eyelids are indicative of trust. ("See, I don't even have to keep my eyes open.")
Without vision, a wealth of communication is lost, leaving a cat literally in the dark as to the intentions of other animals nearby. All is not lost, however, as auditory, olfactory, and tactile signals will help fill in the blanks.
Cats make a variety of sounds in a variety of intonations. McKinley (1982) classified cats' vocalizations into two basic categories – pure (simple) sounds and complex (multiple) sounds. Pure sounds include the growl, squeak, shriek, hiss, spit and chatter. Complex sounds include the mew, meow and moan.
The growl, shriek, hiss and spit are pure sounds that communicate aggression. To another cat there may be some qualitative differences between these warnings. For example, it may be that the hiss and growl signal two levels of warning whereas the spit and shriek are more extreme utterances inferring that "boiling point" has been reached or exceeded.
The only benign communication in the pure sound group is the squeak – a high-pitched, raspy cry given in play or in anticipation of feeding.
Chattering is not a sound used in communication but rather is reflexive chattering of the teeth brought about by frustrated predatory ambitions (i.e. seeing birds on a feeder on the other side of a window).
Two complex sounds are interesting: the mew and the meow. The mew may just be the kittenish equivalent of the adult meow as, like the meow, it signals a wish for attention from a benevolent attention-seeker. The meow is made up of two sounds, phonetically "me" and "ow." The former is thought to mean "here I am" and the latter "don't hurt me." Kittens, of course, direct the mew toward their mothers. Adult cats direct the meow toward humans perhaps because, as cats' feeders and groomers, we fill a parental role.
Cats groom other cats, and sometimes their significant humans, as an altruistic stress-relieving measure. Perhaps they expect payback at some time in the future (reciprocal altruism) but it is nonetheless an affectionate gesture. This form of grooming is tendered and received in a way that indicates close relationships or mutual bonding.
Cats will sometimes indicate their intentions by their movements. Walking directly toward another cat or person is an indication that she is about to initiate an interaction some way. If the cat's tense body posture or angry vocalizations indicate trouble it may be a good time to run and hide, though if the cat appears relaxed and happy and is squeaking softly it may simply be trying to get your attention.
When they want to be fed, cats will often walk obliquely in front of an owner seemingly trying to trip them up. Entwining themselves around a stationary person's legs also indicates that it's time for food or attention. Bunting, or head rubbing, is an affectionate gesture that involves marking with special biological scents, called pheromones. Urine marking and furniture scratching – other olfactory communications – signal anxiety or frustration.
I reserve the term "body language" for those shows or alterations in a cat's body "morph" (shape and appearance) that convey a signal to others. Of particular interest are eye signs (like pupillary dilatation), ear signs (e.g. ears swiveled back), head/neck position, and tail position. Body morph changes, however, must be interpreted in context for their significance to be appreciated.