Why cats don’t go in heat during winter?

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Curious about your new kittens and her heat cycle? So are many cat owners as most female cats go in heat during their mating season from early spring through early fall. But why don’t cats go into heat during winter?

In this article, you’ll learn why cats don’t go in heat during winter, how natural lighting  impacts the heat cycle of a female cat, and when your cat will have her first heat cycle.

Grey kitten in the snow with Holiday lights in the background seemingly asking why cats don't go into heat during winter
Why don’t I go into heat in winter?

Table of Contents

Cats aren’t the only seasonal breeders

Unlike human females who cycle monthly, or dogs who usually cycle twice a year, cats have a specific pattern of how their reproductive cycle occurs. The most unique thing about this is something called “seasonal breeding”. This breeding season means that cats don’t go into heat during winter.

Horses, lemurs, groundhogs, and hamsters are a few examples of animals that become responsive to breeding when the amount of daylight exceeds a specific threshold. Once your cat reaches sexual maturity, they’ll need 12 hours of daylight to initiate a heat cycle.The above mentioned animals are known as long day breeders. This means they breed only when there is a long day. Additionally, there are short day breeders in the animal kingdom as well. A few of these are sheep, goat, fox, deer, and moose.

Why the amount of daylight affects the feline heat cycle

Okay, the amount of daylight hours influences when feline heat cycles and when other animals can breed. But why?

The main purpose, from a cat’s point of view, is to ensure kittens aren’t born during the winter season. This is a period when the main food sources of cats in the wild are hibernating. Cats in the wild feed on mice and rabbits. So over the eons of evolution of cats, they adapted to ensure the best chance of survival of their kittens. This of course carried over to domestic cats.

It’s amazing that cats figured out this great workaround.  They evolved to not have their estrus cycle during winter which makes sure the first litter of kittens will appear only at the middle of the spring.

This is controlled by the amount of daylight. Studies show that cats need at least 12 hours of continuous daylight to start their estrus period. In most parts of the world, this happens for a period of six months during the warm season.

How daylight affects the heat cycle of cats?

So the obvious next question is, how does this work? How can such a vague thing like sunlight be responsible for the breeding of cats? If you think about it, most living things are influenced by the natural light coming from the sun. Most notable would be plants creating oxygen in a process known as photosynthesis.

Have you heard a hormone called Melatonin? Carrying its name derived from Greek Melos – black, dark, it is also known as the sleep hormone. It’s released by most animals in the absence of light and helps to maintain the sleep – wake cycle. This is why you feel sleepy during rainy days and why it’s hard to get back to sleep if you turned on light during the night.

In addition to the main functions of melatonin, there are several more. Did you know that melatonin suppresses the Luteinizing Hormone (LH) and Follicle-stimulating hormones (FSH)? Both of these are very important in developing and maintaining the heat cycle in most mammal females. If you want more details on this, please read our article about hormonal activity of a cat during the heat, which is part of our series about cats going in heat.

One important thing to note is that not all cats stop cycling during winter. Short haired cats are known to cycle throughout the whole year. Additionally, artificial light can easily interfere with natural hormonal regulations of a female cat as well.

When will a cat have their first heat?

As your female kitten grows up, you might wonder what is the age when she will first come in heat.  Cats come in heat for the first time when they reach sexual maturity. Normally this is between six and ten months of age.  While it can be as early as 4 months of age and as late as 18 months.

Some cat breeds have a predisposition to start coming in heat earlier or later. Most short haired cat breeds tend to have their first heat at an earlier age than long haired cats. For example, Persian cats usually are reported coming in the heat for the first time no sooner than 12 months of age.

Should you worry if your cat isn’t coming into heat?

So, what if your cat has reached their one year birthday, but hasn’t yet come into heat? Is something wrong? Should you worried?

If you aren’t planning to breed your cat, then you shouldn’t worry about her coming into her first heat. Just spay your cat at an appropriate age, which is starting from age of five to six months. Of course, please consult with your veterinarian on when to schedule this surgery. This is the first conversation we have with new pet parents of both dogs and cats in our veterinary clinic. We recommend spaying and neutering as this helps prevent unwanted pregnancies, reduces sexually driven behavioral problems, and reduces some health issues such as mammary cancers in females and testicular cancer in males. There are lots of positive benefits so definitely have this discussion with your veterinarian.

And forget about the fairy tales told by some people that your cat should have a heat cycle or a litter of kittens before spaying her. There is not scientific evidence to that, even the other way around. Studies show if you spay your cat early, risks of mammary tumors development are minimized. And best of all, no unwanted pregnancies, no potential mates hounding your little girl, and not having to deal with the signs of heat like vaginal discharge on your carpet. 

On the contrary, if you do intend to breed your cat, you should pay attention if your cat doesn’t come in heat at an age expected. You should consult with your veterinarian if you suspect there might be a problem with you cat’s reproductive system.

However, most veterinarians would suggest not to worry if your cat doesn’t come in heat up to the age of 18 months. If it’s still not happening after then, some tests may be necessary to assess your cat’s reproductive health.

You have learned why cats don’t go in heat during winter, how natural lighting impacts the heat cycle of a female cat, and when your cat will have her first heat cycle. This will go a long way towards keeping your pet cat happy and healthy.  And keeping your Pet Happy is what we all want.

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