two silver tabby kittens that look like twins, with a black kitten in the background

Can cats have twins? We asked a vet!

Cats, if left to their own devices and unneutered, are prolific breeders. Although female cats can get pregnant all year, kittening season occurs during spring. Female cats come into season most often when the days are getting longer, so more litters are born in late spring. Female cats can even get pregnant while they are nursing a new-born litter, so it’s important to keep your cat inside at this time to avoid another pregnancy.

How many kittens does a cat usually have?

Litter size can vary dramatically in cats, ranging from one to twelve kittens and averaging at about four.  Litter size varies wildly because female cats can become pregnant with litters from different fathers at the same time. Therefore, it is not uncommon for litters of kittens to be born with different markings. Those that share similar markings may share the same father. But can cats have twins?

Twins in cats

Of course, a cat can give birth to a litter of two kittens, who are not genetically identical but have shared the womb during the same pregnancy and these may be referred to as twins. The average litter size is higher than two, but it is not uncommon to have a litter of two.

Equally, within one litter where there are multiple fathers, there may be two kittens that have the same father, and these may also be called twins, similar to paternal twins in humans. But what about identical twins?

Identical twins

Genetically identical twins happen when a fertilized egg splits into two separate embryos. This is rare in cats, but it does occasionally happen. Most kittens that look similar are more likely just to share the same parents rather than being truly identical. Interestingly, kittens can share the exact same genetic make-up, but this does not necessarily mean that they share identical markings, since the genes that code for color and markings can be expressed slightly differently.

How do I know if my kittens are twins?

Because non-genetically-identical kittens from the same litter can have similar markings just because they share the same parents, and genetically identical kittens can have different markings, it can be very difficult to determine whether or not two kittens are twins, in the genetic sense. In fact, the only way to be certain whether two kittens are identical twins would be to perform a DNA test on each of them and compare the results.

Conclusion

Although kittens can indeed be genetically identical twins, it is very rare. It is far more common that two kittens are ‘twins’ only in the sense that they are two kittens from the same pregnancy who share the same mother and father, but are not the product of a fertilized egg splitting into two. If you want to find out if your kittens are identical twins, speak to your veterinarian about a DNA test.

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