Why Do Cats Meow?

As independent hunters, cats have limited need for an extensive vocal repertory. Cat-to-cat vocalizations are generally limited to communicating with one’s kittens, one’s sexual partners and one’s potential enemies. There is also an array of vocalizations used when attempting to communicate with humans.
The purr is the most common sound issued by cats and yet one of the least understood. One of the first vocalizations uttered (along with grunts), kittens a few hours old purr as they knead the queen’s chest and nurse. The sound is made while the cat is both inhaling and exhaling with an instantaneous break between breaths. Built-up pressure created by the opening and closing of the glottis results in a sudden separation of the vocal folds, creating the purr. While often heard when the cat seems particularly content, those familiar with handling cats in pain or near death know they also purr when under duress, the reason for which is yet unknown.
The second most common vocalization is the meow. Rarely heard between cats, this vocalization seems tailor-made for communication between our species. Early on, cats notice that meowing brings attention, contact, food and play from their human companions. Some behaviorists suggest that certain cats seem to alter their meows to suit different purposes and that some guardians can differentiate between, say, the “I’m hungry meow” from the “let me out” meow. Others would say this is more context-driven than actually being able to infer meaning by sound alone.
The meow is the most used of the vowel patterns – vocalizations produced with the mouth first open and then gradually closing. Several forms of demand also fit into this category. The sound cats make when highly aroused by the sight of prey is called chirping. When a cat is frustrated, like when an indoor cat finds he is unable to get to the birds at the feeder, you may hear him chatter. And when a neonate kitten is cold, isolated from his mother or trapped, he issues a distress call (also called an anger wail in some literature). As the kitten matures, the distress call is used when play is too rough or the cat finds something else to protest.
All threat vocalizations are produced with the mouth held open. These sounds mirror the cat’s intense emotional state. A hiss is uttered when a cat is surprised by an enemy. A high-pitched shriek or scream is expressed when the cat is in pain or fearful and aggressive. Snarling is often heard when two toms are in the midst of a fight over territory or female attention. And a long, low-pitched growl warns of danger.
By changing volume, intensity and number of repetitions of the vocalizations and backing them up with expressive body language and olfactory signaling, cats ensure their messages are received and that their needs are met.