Cats meow for a variety of reasons, primarily to communicate with humans. A cat may keep meowing to seek attention, express hunger or thirst, or indicate stress, pain, or illness. Additionally, it can be a learned behavior where the cat realizes meowing gets a response from its owner. Other reasons include boredom, loneliness, changes in their environment, or aging-related cognitive dysfunction. Specific medical conditions like kidney disease, hyperthyroidism, or urinary problems can also cause increased vocalization. Some breeds are naturally more vocal, and cats in heat may meow loudly as part of mating behavior.