Research has found some 19 different vocal patterns in cats, with individuals adding personal sounds only used with their owners. Most sounds fall into three groups: closed mouth greeting (purr or chirrup), fixed open mouth emotional sounds (hissing, growling or spitting), and open then closed mouth ‘meow’, which cats change depending on the circumstance. Kittens meow to communicate hunger, cold or fear to their mum. Adults communicate with each other by hissing, growling and using body language and scent. An exception is the ‘yowl’ (similar to a meow but more drawn out and melodic). Adult cats yowl at each other specifically during breeding season. Meowing in adults is usually reserved for communicating with humans.