Cat in Heat – Signs, Duration of Estrus in Cats

What is estrus?   Signs    Duration     Frequency     Prevention


Estrus in cats


Cat estrus at a glance:

  • About: Estrus (heat) occurs when a cat comes into heat and is receptive to mating.
  • Onset: It starts in puberty, between 6-10 months of age, but can occur in some cats as young as four months.
  • Symptoms: Calling (loud yowling), rolling, raising her hindquarters when stroked, genital licking and in some cases spraying.
  • Duration: Estrus lasts approximately 4-5 days, if she doesn’t become pregnant estrus will occur again every 2-3 weeks.
  • Prevention: The best way to prevent estrus and unwanted pregnancy is to spay your cat.

What is a cat in heat?

Eastrus (cat in heat/calling) is the fertile and receptive period 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 actually four phases of the cat’s heat cycle:

  • Proestrus
  • Estrus
  • Metestrus
  • Diestrus

This article will look at the second phase estrus, where the female is receptive to mating.

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 or older.

Cat mating season:

Cats are seasonal maters (although some can go into heat and produce a litter at any time of the year). Typically the feline mating season begins in spring when the days become longer and continues until autumn. Cats are polyestrous, which means they will have more than one heat cycle in a year.

Signs of estrus:

Your 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.

  • If she is stroked, she may 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 (lordosis)
  • Persistent vocalisation, this is often louder than usual and can be described as a yowl.
  • Licking of the genital region
  • Clear discharge from her vagina
  • Loss of appetite
  • She may spray on vertical surfaces

Some cats are what is known as silent callers and may display none of the above signs.

It may appear so, but a cat is not in pain when she is in heat.

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.

Do cats bleed when she is in heat?

No, unlike dogs, cats do not bleed when they are in heat, nor do they menstruate (have their period). If your cat is bleeding, take her to the veterinarian.

Duration of estrus:

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). Not only will this prevent ‘calling’ and ensure no unwanted kittens are brought into the world but there are also health benefits to desexing a female 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 unknown/untested tom.

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 permit your cat to mate.

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.

Also, unless you have tested the tom (male cat), there is no way you will know if he has either FIV or FeLV, both of which are viruses which are fatal in cats.

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, however.

Pregnancy signs:

The first sign of pregnancy is pinking-up, where the nipples become pinker and slightly swollen. This happens around the third week of pregnancy.

Weight gain occurs around the fourth week of pregnancy.

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.

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