What is a cat in heat?
Estrus (heat or calling) is where a an entire female cat is fertile and receptive to mating. It usually seasonal but can depend on a number of factors including the number of daylight hours, age and general health of the cat.
There are four phases of the cat’s heat cycle:
This article looks at the second phase, estrus.
At what age does estrus begin?
Estrus begins at puberty when this starts varies from cat to cat and breed. Some breeds
such as the Siamese can call as early as four or five months. Other breeds may not reach
sexual maturity until 10 months of age.
Cat mating season:
Most cats are seasonal maters, although some do go into heat and produce a litter at
any time of the year. Typically the feline mating season begins in spring when the days start to become longer and runs through until autumn. Cats are polyestrous, which means they will have more than one heat cycle in a year.
Signs of estrus in cats:
- Affection: The cat may become extra affectionate towards people and other cats, rubbing against
their legs, or weaving in and out between their legs or rolling on the floor.
- Posture: If she is stroked, she may assume a mating position and lay her front half low, and raise her hindquarters, treading up and down with her hind feet, and move her tail from side to side. This is known as lordosis.
- Persistent vocalisation: This is often louder than usual and can be described as a
- Licking of the genital region: Beyond normal grooming, the vulva is often swollen with a clear discharge. If the discharge is cloudy or has a foul odour, see your veterinarian as the cat may have pyometra (an infection of the uterus).
- Spraying: On vertical surfaces such as walls and chairs. The female cat’s urine contains pheromones to attract male cats.
Some cats are silent callers and may display none of the above signs.
If your cat is in heat, keep her indoors. If she is an indoor cat already, be extra careful to keep windows and doors closed because she will be keen to get to a male cat and mate. Keep her away from intact male cats.
How long is a cat in heat?
Estrus typically lasts between 4-5 days. If your cat doesn’t become pregnant then it will
repeat every 14 to 21 days until she does become pregnant or the season’s change.
There are three possible outcomes:
- Pregnancy occurs.
- The cat mates but does not become pregnant, has a pseudopregnancy (false
pregnancy) and comes back into heat 30 or so days later.
- The cat doesn’t mate or become pregnant and comes into heat 14 to 21 days later.
Frequency of estrus:
If the cat doesn’t become pregnant during a period of heat, she will go out of season for 2 –3 weeks and then come back into heat. This can continue until the days shorten in autumn (around September in the Northern Hemisphere and March in the Southern Hemisphere).
The only guaranteed way to prevent a queen from coming into heat is to have her desexed
(spayed). This also prevents unwanted kittens and provides a number of health benefits to the cat.
Entire cats are at risk of developing cancer of the uterus or ovaries, pyometra, and breast cancer.
Do sibling cats mate?
Yes, brothers and sisters will mate, fathers and daughters, mothers and sons. Cats do not
discriminate when it comes to mating.
Is it possible for a litter of kittens to have different fathers?
Yes, cats are induced ovulators, their eggs are released after they have mated and can
survive for up to 24 hours. If your cat mates with multiple male cats, then the kittens born
can potentially have different fathers.
What should I do if my cat comes into heat?
Keep her indoors and away from any entire (Tom) male cats and book an appointment with
your veterinarian as soon as possible.
If she does get out and mate, it is not too late. She can still be desexed. Speak to your
veterinarian about this. He may also wish to test for FIV and FeLV if she has mated with an
Should I let my cat mate when she is in season?
Unless you are a registered breeder, and this is a planned mating then no, you should not
allow your cat to mate for several reasons.
- There is a huge cat overpopulation problem and breeding your cat just contributes to this.
- For every kitten you have, which you may pass on to friends or neighbours, that is one
kitten in a shelter who could have been rehomed.
- Unless you have tested the tom (male cat), there is no way you will know if he has
either feline immunodeficiency virus (FIV) or feline leukemia virus (FeLV).
- Desexing (also known as spaying) can be performed while your cat is in heat, but
veterinarians typically prefer to spay a cat who isn’t in estrus.
My female cat has been spayed but she is still coming into heat:
This sometimes happens in spayed cats if there are any remnants of the ovaries left behind
during her spaying operation. This tiny portion of the ovary continues to produce hormones
which trigger the estrus cycle in the cat. It is not possible for her to become pregnant,
The first sign of pregnancy is pinking-up, where the nipples become pinker and slightly
swollen which occurs around the third week of pregnancy.
Weight gain occurs around the fourth week of pregnancy.
Do female cats have periods?
Female cats do not shed their uterine lining and there is no period.
How long is a cat pregnant?
A cat is pregnant for approximately 63 days.
How many kittens are in a litter?
This depends. First-time mothers may have a small litter of one or two. The average
number of kittens in a litter is approximately 4 – 6.