Understanding the Estrous Cycle in Cats

The reproductive cycle of female cats is different from that of women or dogs. Women have a monthly a menstrual cycle, during which the ovaries produce a viable egg and then, if fertilization does not occur, the uterus sheds a discharge. There is no specific period of receptivity to mating (and its opposite, a lack of receptivity) among humans-although certainly, there are times when we feel more romantic!

Cats and dogs, on the other hand, have an estrous cycle, during which the ovary is primed to produce an egg and the female is specifically receptive to mating. The estrous cycle consists of estrus, the period of mating, preceded by proestrus and followed by metestrus. During the breeding season, one estrus cycle is separated from the next by a brief inactive period known as diestrus. The longer quiescent period during the remainder of the year is called anestrus (literally "no estrus").

Intact female cats, called queens, reach sexual maturity at about seven to nine months. The age of sexual maturity varies with individuals as well as with breed - Persian cats, for example, tend to experience their first estrus much later.

Do Cats Have a Breeding Season?

In most cases, yes! Unlike dogs, for whom estrus occurs approximately every six months, female cats go into heat several times during a single, prolonged breeding season. The breeding season is controlled by the number of hours of daylight (the same is true of horses). In the Northern Hemisphere, the feline breeding season lasts roughly from February to September. Many cats (not all) will stop their estrus cycles (go into anestrus) in the fall and early winter, when there are fewer daylight hours. It is interesting to note, however, that indoor cats may cycle throughout the year because electric lights give them about the same light/dark cycle throughout the four seasons.

Behavior Changes During the Estrous Cycle

Female cats exhibit dramatic changes in behavior while they are in estrus. Owners-often unsure about the reason for these changes-notice increased affection, purring, and rubbing. The cats will roll from side to side and meow or yowl much more than they typically do-a lot more! At the peak of estrus, when the female actively invites the male, she may lie with chest and forelegs down on the ground, her hind legs stretching upwards and treading-inviting a mate. These behavior changes can be so striking that unknowing human companions may become alarmed and call the veterinarian to report a mysterious illness!