Mammals tend to have two sexes, XX and XY, which we commonly refer to as female and male. Biologically, we are aware of the general differences between those with these chromosomes in humans, but do you know the differences when it comes to your cat? And are there any other chromosome combinations that can exist? Whether you have kittens you need to determine the sex of, are adopting a stray, or are considering which sex would better suit your home, it is important to understand the differences between female and male cats.
Your Cats and Gender
Generally speaking, your cat is most likely to have either a XX or XY chromosomes. However, there are some other very rare combinations that can exist. For example, male calico cats and male tortoiseshell cats can only exist through chimerism or through having XXY chromosomes. These conditions, that are outlined below, are rare, meaning you can make a fairly educated guess that, if you have a calico or tortoiseshell cat, they are probably female.
Chimerism occurs when a cat has two sets of DNA due to being formed of two separate zygotes in the womb which otherwise would have produced another sibling. This allows for different cells to have different X chromosomes and, as the X chromosome also determines color, their fur will change color depending on which X chromosome is present in that cell.
Chimerism does not cause your cat to be sterile, but they will not pass on their coat pattern. Instead, they will just pass on one of their colors to their female offspring, through one of their X chromosomes, and will not pass on any color to their male offspring, who only inherit a Y chromosome from their fathers.
XXY chromosomes, on the other hand, influence color due to there being two X chromosomes in every cell. Some cells turn on one color, while others turn on a different color. Cats with XXY chromosomes are referred to as Klinefelter males, but are generally sterile so cannot produce offspring to pass on their genes.
This condition is very rare, of course, and it is much more likely that your cat will have XX or XY chromosomes. If you have a calico or tortoiseshell male and are wondering if they are a Klinefelter male, you can always visit your vet who will answer any questions you may have, most often through blood and urine samples that will reveal the abnormal hormone levels that are often associated with Klinefelter syndrome.
There are also other sexual developmental issues that can occur, but, for the average cat with XX and XY chromosomes, there are ways you may be able to distinguish your cat’s sex without visiting the vet. If you are at all unsure, you should visit a vet to get their opinion. They will be able to clarify if your cat is a boy or a girl, which will have a number of implications. It is important to know the gender of your cat or kitten, preferably before you take them in, because:
- It is helpful to know what their healthy weight should be, which differs between males and females
- Indoor cats of opposite genders that are sharing an environment are likely to produce offspring if not spayed or neutered
- Female outdoor cats may, similarly, unexpectedly become pregnant
- Males can become aggressive with one another
- Their temperament, and how they fit into your household, can be affected by their sex
Differences in Appearance
Unfortunately, a cat’s sex is harder to determine than a dog’s. Male cats do not have visible genitalia, and both genders will have nipples. Your cat can have a huge variety of characteristics, such as their coat color, fur length, size, and face. This means that it can be very difficult to tell the difference between genders based on these attributes. For example, you cannot tell sex based on the difference between male and female cat faces because there is a huge variety of cat faces based on breeds.
Another common, but vague, method of telling the difference between a male and a female cat is size and weight. Generally, male cats will be bigger than female cats, but you can get naturally small male cats and very large female cats. As a general rule, all cats are about 6 to 12 pounds and 8 to 10 inches high, so a completely average 9 pound cat that is 9 inches tall will be very difficult to determine. This method is also not suitable for kittens as it is based on average adult sizes. Kittens look even more similar to each other than adult cats often do.
Ultimately, your vet is in a much better position to assess the gender of your cat. However, there is one method you can try that is fairly accurate and useful, and it involves lifting their tail.
- Do not force, trap or restrain a cat or kitten into revealing their rear end. You must first gain their trust, or ask the help of someone the cat does trust.
- Pick up the cat and gently lift the tail. If they do not want you to lift their tail, you can try scratching their lower back as this often encourages them to lift up their tail.
- When the tail is up, you should be able to see their genitals and anus. The shape of these should help you to figure out if they are male or female.
- A female cat will have a long slit below the anus that would make the entire area look like an upside down exclamation point. This is the vagina and it should be about half an inch away from the anus.
- A male cat’s rear end will look more like two dots that are further apart than one inch. The shape is more comparable to a colon.
Do I Have a Male or Female Kitten?
Telling the sex of a kitten is even harder than telling the sex of a cat. This is because they are so tiny, and often start at the same size. You won’t be able to tell what their sex is until they are at least 6 weeks old. Remember, you cannot assume that a lack of male genitalia is a sign that the kittens are all male as most male cats do not have visible genitals.
Once your kittens have reached about 8 weeks old, the difference between male and female kittens is pretty much the same as the difference between adult male and female cats. You can then use the method outlined above to try and determine their gender. If you are unsure, as their rear end may still be very small, wait a week or two and check again. You can always ask a vet during a check-up to give their professional opinion.
Differences in Behavior
Now you know how to discern the sex of your cat or kitten, it is important to discuss why it is so important to understand this difference. We’ve already mentioned many of the reasons it is useful to know your cat’s sex, and you may have noticed that most of them have to do with understanding your cat’s behavior.
A cat’s gender has a big impact on their behavior, but whether they are spayed or neutered is also a big factor to consider. Key behavior differences between male and females that have not been spayed or neutered cats include:
- Un-spayed females will go into heat, which will attract male cats and is likely to result in kittens if she comes into contact with a male. During heat, this means a lot of noisy vocalizations, which can be disruptive, rolling on the floor and particularly intrusive attention-seeking. Once they are pregnant, they can become very aggressive and protective. They will also be aggressive towards other female cats who they perceive as rivals.
- Un-neutered males are more likely to act restless, want to go outdoors, be very active, mark their territory with urine, and will be significantly more aggressive, both towards other males and humans. They will also put more effort into learning to be escape artists if they sense a female in heat is nearby.
The benefits of spaying or neutering your cats is often debated among cat owners. It is often claimed that cats are better behaved with these natural urges in check, but, thus far, only the benefits of neutering a male cat have been fully scientifically proven as a male cat that has been spayed is statistically must less likely to be aggressive and spray urine. But, it is widely understood anecdotally by most cat owners, that neutering and spaying can have an affect on certain behaviors.
You cannot assume that spaying or neutering a cat will dramatically change their personality, however. There are many factors that impact your cat’s personality. While there are many reasons to spay or neuter a cat, don’t pin all your hopes on using it as a method to change who your cat is. Some cats will always be aggressive, some female cats will always be loud and talkative, and some males will continue to have the urge to spray urine. Training is the best answer to most issues of unwanted behavior, regardless of the cause. Though, it is always helpful to understand the cause in order to make training as effective as possible.
Although science has yet to definitively prove that spaying or neutering any cat will influence its behavior, personality or temperament, it is still worth considering undertaking the procedure as there are many other benefits to spaying or neutering. These include:
- Avoiding unwanted litters of kittens
- Improving the quality of life of a female cat as spayed females live longer lives
- Improving the quality of life of a male cat as neutered males usually avoid testicular cancer
Is It Better to Have a Male or Female Cat?
It is difficult to tell what is better for your circumstances, but there is definitely not one gender that is better than the other. It isn’t a good idea to base your cat adoption on gender as personalities can vary so much, as we’ve already outlined. Adopting a cat or a kitten is a serious commitment, and we’d advise you visit your local centre many times and get to know each cat individually to see which fits best with you. Gender may end up being a factor, but keep your mind open to bonding with any cat.
You may, however, have some practical considerations to make when you are adopting a new cat or kitten. For example:
- If you are looking to breed your cats, you will, obviously, need a particular gender to partner with your existing cat, and may also need a particular breed and color, depending on your aims.
- If you want to adopt two cats that are more likely to get along, you will want to avoid two Un-neutered adult males. Keep in mind that kittens that are brought up together, regardless of gender, are always more likely to get along later in life.
- If you want to avoid excessive vocalizations, perhaps because you work from home and need peace and quiet, then you may want to avoid an Un-spayed female cat.
Ultimately, sex and gender is a factor you may want to consider when adopting a kitten or cat, particularly if you know you don’t want to spay or neuter them, but it is just one factor that could determine personality, alongside:
- Their individual temperament
- Their breed
- Their previous training
- Their environment
- Their health
- Whether they have been spayed or neutered
The best way to ensure a personality that fits in with your particular household is to look into breed personalities and temperaments, as well as gender, and then get a kitten that you are willing to put the effort into training and caring for. You can then also consider spaying or neutering, depending on your circumstances and needs.