Heat, Oestrus, Estrus
All of the above terms are correct in describing female cats' periods of receptiveness to mating, but I will refer to them as the more often-used "heat cycles."
The Breeding Season in Cats
The breeding season in cats is practically year-round, running as early as February, and as late as December, but in the western hemisphere, March through September is generally regarded as the breeding season.
Rescue people dread "Kitten Season" because it means that in kill shelters, the new crop of kittens will eliminate any chances of adoption for older cats, including last year's kittens. If for no other reason, this alone is ample justification for the spaying and neutering of pet cats.
Heat Cycles in Cats
Cats are referred to as "polyestrus," which means that they will go into heat cycles periodically during their fertile years. These heat cycles may start as early as the fourth or fifth month of a kitten's life, and will continue until she is either bred or spayed. Heat cycles in cats last from several days to two weeks or longer, and repeat every two to three weeks. You can see then, how a female cat may almost always seem to be in heat.
No one can say with any accuracy that heat cycles are painful to cats; however from the calling (loud yowling) and other symptoms they exhibit, it would appear that they are very uncomfortable. For detailed information on how to tell if a female cat is in heat, see this how-to article. If you still are not certain, watch this video of a young cat in heat.
- Heat, oestrus, and estrus all refer to heat cycles in cats.
- The breeding season in cats lasts almost year-round.
- Heat cycles can start as early as four or five months in a female kitten.
- Heat cycles in cats last from several days to two weeks or more
- Heat cycles in cats repeat every two to three weeks until the cat is spayed or becomes pregnant.
- Heat cycles may cause pain or discomfort in cats.