How to Identify a Cat's Sex

Written and verified by the vet Daniel Aguilar

Last update: 22 December, 2022

You might think that, as with other species, it’s very easy to identify a cat’s sex. The truth, however, is that it’s not as simple as it seems and, if you don’t pay the necessary attention, you could have been calling your pet the wrong name for a long time now!

The biological world of a cat is very diverse, full of peculiar aspects and curiosities that, without a doubt, make them very special. We invite you to continue reading in order to get to know more about the reproductive traits in felids and become a master when it comes to identifying a cat’s sex.

What are the main characteristics of the male cat?

First of all, it should be noted that, in both males and females, it’s even more complicated to identify the sex when it comes to kittens or neutered felines. The genitalia in both sexes are very similar at birth. Only at day 21 are there some marked differences that begin to be observed.

In the case of male cats, you’ll find 3 main structures. They are the following:

• Penis: Covered with a large amount of hair – which makes it difficult to appreciate – the penis is located on the testicles and between the thighs. It’s usually very small, similar to testicular size.
• Scrotum: Easier to observe in adult cats, it’s a bag covered with hair where the two testicles are located, which are usually the size of a cherry pit. During palpation of neutered cats this small empty pouch can still be felt.
• Anus: It’s separated from the penis by at least 3 centimeters in adult cats and 1 centimeter in newborns. The distance between anus and genitalia is an important and easily observed characteristic to identify a cat’s sex.

How are females characterized?

At first glance, it may seem a bit easier to identify female cats, as externally they have fewer structures than males. In them, only the anus and vulva stand out.

As in males, the female anus of the cat is superior to the genitals. The difference lies in the distance between them: in females it’s separated from the vulva only by 1 centimeter. Comparing this figure with that of males — adults and young — it will always be lower.

Very close to the anus is a small vertical groove, which leads to the vulva. In some occasions, the hair obstructs it, which can cause some confusion when it comes to identifying a cat’s sex.

Tips for handling your cat in exploration

When you decide to perform an examination of your cat’s genitals to find out its sex, whether male or female, we recommend doing the following:

• Start by making your pet comfortable. Use positive reinforcement like caresses and good words.
• Gently lift the cat’s tail and look at its genitals. This movement could annoy them and make them feel the need to escape, so watch out for possible scratches and bites. Some specimens, when caressing their backs, tend to lift their tails by themselves. Take advantage of this situation and quickly observe the genital area.
• In the case of kittens, try to be brief and don’t push the kitten too far away from where its mother is.

Can you identify a cat’s sex based on their size and hair color?

The answer to this question is yes. Normally, male cats tend to be larger and have a different complexion from females. Although this characteristic usually occurs in many species, there may always be some exceptions for various factors.

We’re that you’re intrigued how the color of the cat’s hair can indeed help the tutor to identify the sex of the cats. But, how is this possible?

Currently, there’s a great variety in the colors in cat fur, all as a result of the crossing that has occurred between different breeds. The phenotypic characteristics of cats – external physical characteristics – are governed by their genes and the combination of alleles, inherited from the father and mother.

Males and females can have a coat of a single color or a mixture of 2, but it’s only the female cats that have a combination of 3 colors – tortoiseshell or calico. This characteristic is given by inheritance linked to the dominant ‘x’ chromosome.

The alleles that dominate the color red and black – in tricolor cats – are found in this chromosome. Females have two ‘x’ chromosomes, males have one ‘x’ and one ‘y’. Therefore, the presence of 3 colors in males will never appear, unless there’s some unusual genetic alteration.

Curiosities between the sex of cats

Every animal on the planet has certain characteristics that help it stand out from the rest. Cats are no exception; they have a very interesting reproductive anatomy, which performs certain functions during copulation.

For example, it should be noted that the penis of males is somewhat atypical. Inside it is a bone known that helps them to penetrate even in the absence of an erection. In addition, its glans is full of small spicules or thorns that appear when it reaches sexual maturity.

Once you know how to identify a cat’s sex and distinguish a male from a female, you could observe this peculiar trait. The reason why the cat has this anatomy has its reasons, and here are the main ones:

• The spines on the cat’s penis help to remove semen left in the vaginal canal by other cats. During the reproductive stage, the cat is usually very sexually active. Therefore, it’s most likely that it has already been mounted by other males that are nearby.
• During mating, these keratin spicules rub against the female’s vaginal walls, stimulating the release of hormones and the maturation of the eggs. It’s a fact that cats can feel pain during sexual intercourse, however, they can reach orgasm quickly and shorten the duration of intercourse.
• The spicules allow the male to have a greater anchorage to the female, helping the reproduction to be successful.

So, now that you’re an expert in identifying a cat’s sex, we invite you to share this information so that everyone can distinguish if they have a male or female cat at home. Many people may get a real surprise!