Last updated: August 10, 2016
When a cat enters the phase of the reproductive cycle in which she is receptive to males and mating, she is considered to be “in heat.” Another name for this phase in a female cat is estrus.
When a cat is in estrus, she displays some remarkable changes in behavior. Understanding and predicting your cat’s heat cycle will help you manage her health, as well as plan for breeding if that is your goal.
Young Cats and Estrus
A cat has her first heat cycle when she begins puberty. Outdoor or feral cats may reach sexual maturity much earlier than domesticated indoor cats, especially if the outdoor cats are in the presence of unneutered males. All female cats that are not spayed will come into heat, and the first heat typically occurs when a cat reaches about 80% of her adult size.
For short-haired cats, the first heat usually occurs around 6 months of age, but in a few cats it occurs as early as 4 months. Siamese and Burmese are breeds that often go into heat for the first time at the earliest ages.
Long-haired cat breeds, such as Persians, tend do go through puberty at slightly later ages, ranging from 10 months to as many as 18 months. The average age for most cats to experience their first heat is 5 to 6 months old. Therefore, it is possible for a cat to come into heat and become pregnant when she is still a kitten.
The Effect of Daylight on a Cat’s Reproductive Cycle
Unlike many members of the animal kingdom, outdoor cats do not cycle regularly throughout the year. Instead, a cat’s reproductive cycle is determined by her amount of daylight exposure, which changes with the seasons of the year.
When there is more daylight and nights are shorter, a female cat’s brain produces less melatonin. Ultimately, this chemical change within a cat causes her to go into heat during spring and summer, when the days are longer. This particular breeding season benefits feral cats as their kittens are not born during the harshest times of winter, when their kittens’ chances of survival would be lower.
As with the timing of a cat’s first heat cycle, various cat breeds react to changes in daylight differently. Specifically, long-haired cats are more sensitive to light than short-haired breeds.
But what about your house cat? She’s exposed to indoor lighting, which creates an artificial day and night cycle. She may come into heat anytime during the year, and her heat cycle will be less predictable than that of an outdoor cat.
How Do I Know If My Cat Is in Heat?
The signs that your cat is in heat are unmistakable, but she will also begin to show symptoms prior to coming in heat. She may have an increased appetite and act restless. Your cat may also utter low calls and show you more affection than usual prior to coming into heat.
Once your cat is in heat, she will become quite vocal, even making loud yowling noises. Her cries may sound so alarming that she sounds like she is in pain, but it is just her attempt to call a mate.
Your cat will also urinate more frequently when she is in heat, and her urine will have a much stronger odor than normal due to higher estrogen levels. Unfortunately, your cat may even lift her tail and spray urine on objects. Cats in heat rarely spray on floors and carpets. Instead, they tend to choose vertical objects such as furniture, walls, and doors.
Some cats in heat will roll around on the ground, and at other times, they may assume the breeding position, which is characterized by holding the head and front legs low and holding the rear in a higher position. When your cat is ready to breed, she may display the tail deflection reflex, which means that she sticks her bottom in the air and moves her tail to one side when you pet her lower back. Another typical behavior of a cat in heat is to excessively lick her vulva, which will become swollen and uncomfortable during estrus.
You must be especially careful when your cat is in heat because she may repeatedly attempt to escape from your home to find a mate. You may even find that she claws at your windows and tries to run out an open door.
During your cat’s estrus, you may notice the presence of tomcats in your yard, and the tomcats may spray your house with urine. This is another time for caution as tomcats may even attempt to enter your house and mate with your cat.
How Long Will My Cat’s Heat Cycle Last?
After all the yowling and cat craziness, you probably can’t wait for the end of your cat’s heat cycle! What should you expect in terms of duration, and when can you expect for it to happen again?
The length of a cat’s estrus can vary greatly, but it most commonly lasts from 4 to 10 days. The timing of the next heat depends on the cat’s exposure to daylight.
Indoor cats that come into heat year round may experience estrus every 14 to 21 days. A cat that is pregnant may come into heat as soon as 7 days after giving birth, but the typical timing is around 4 weeks.
If you wish to immediately stop a heat cycle or prevent the next one, you can take your cat to the vet for medication or hormone injections. Another way to stop your cat’s reproductive cycle is to have her spayed.
Spaying a cat during estrus is possible, but it’s not ideal as complications may arise. Most vets recommend that you have your cat spayed before her first heat cycle. Cats that are spayed after experiencing a heat cycle may continue to exhibit estrus-typical behaviors such as spraying.
When Will My Cat Stop Coming into Heat?
If you choose not to spay your cat, she will never quit coming into heat. Menopause does not exist in cats, and your cat is capable of becoming pregnant even at an advanced age.
Pregnancy in an older cat may be more difficult and complicated than in a younger cat. Pregnancy is physically demanding on a cat, and even professional cat breeders typically spay their cats at the age of 5.
Managing Your Cat’s Reproductive Health
Unless you plan to responsibly breed your cat, animal health experts say that there is no advantage to letting your cat come into heat prior to being spayed. The belief that your cat will be more affectionate if you allow her to come into heat or have a litter of kittens prior to being spayed has been proven a myth.
A cat in heat that successfully leaves your house to breed is at risk for contracting an infectious disease from any male with which she attempts to mate. If you want to avoid having an unwanted litter of kittens or dealing with your cat’s estrus cycle, then contact your vet for advice regarding spaying your cat.