Why cats don’t go in heat during winter?

Curious about cat heat cycles? So are many cat owners as most female cats go in heat during their mating season from early spring through early fall. In this article, we will explain why cats don’t go in heat during winter and how natural lighting can have its impact on the heat cycle of a female cat.

Unlike people who cycle monthly, or dogs who usually cycle twice a year, cats have a specific pattern of how their heat cycle occurs. The most unique thing about this is something called “seasonal breeding”.  That is, cats do not mate during winter.

Cats are not the only seasonal breeders.

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. Cats 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 breeding of cats

Okay, the amount of daylight influences when cats and other animals can breed. But why?

The main purpose, from a cat’s point of view, is to ensure kittens are not born during winter. 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 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 a great workaround – cats do not go in heat during winter.  This makes sure the first 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 cycling.  In the most part of the world, this happens for a period of six months during the warm season.

How daylight can affect 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 names Melatonin? Carrying its name derived from Greek Melos – black, dark, it is also known as sleep hormone. It is 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 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 lighting can easily interfere with natural hormonal regulations of a female cat as well.

But for most cats during winter, when there is plenty of melatonin, cats don’t breed. Of course during spring and summer, when days become longer and melatonin levels decrease, cats resume to regular cycling frequency, and cat give a birth at times when their prey is abundant. So now you know why cats don’t go into heat in winter.