Cats exhibit symptoms when they are in heat, but these symptoms are primarily behavioral. Some cats may develop an enlarged vulva, but this is usually not obvious to the average owner.
Cats in heat may become unusually affectionate to their owners. They often rub excessively on furniture, people or the floor. Some cats may demand affection and then react by biting when they are stroked or picked up. Many raise their hindquarters when stroked along the back. Cats in heat often urinate more frequently than normal and may spray urine on walls or furniture in an effort to attract a mate. When in heat, cats often vocalize loudly and incessantly with howls that are sometimes mistaken for cries of pain.