Unneutered cats are prolific breeders when left to their own devices, with females often becoming pregnant from multiple fathers. One of our readers asked us whether kittens from the same litter can be twins, and we asked dr. Hannah Godfrey for an answer. So, can cats have twins?
Twins in cats
Wikipedia defines twins as two animals born during the same pregnancy. If we go by their definition, all kittens born in the same litter are technically twins, so cats can indeed have twins.
But this is not the end of the story. See, while two kittens from a litter may have shared the womb during pregnancy, they can have different fathers. If they do share the same parents, their genes and appearance are more likely to match, and they are what we would call paternal twins in humans. Paternal twin kittens can still look very different, which is explained in this quote from Basepaws:
However, even those kittens who have both of the same parents, have likely randomly inherited a number of different gene combinations. This means that while certain genetic traits will be shared by the siblings, every sibling will be genetically unique. This remains untrue only for identical twin cats.https://basepaws.com/
So what about twins that are exactly the same? Does that happen in cats? Yes, and that’s what we call identical twins.
Kittens that got the exact same parts of mom and dad are what we call genetically identical. These types of “carbon copy” twins are one of nature’s accidents, and this can happen when a fertilized egg splits into two separate embryos. This is extremely rare in cats.
So while it’s definitely possible, when two kittens look similar, the more likely explanation is that they share the same parents, rather than being truly genetically identical.
How do I know if my kittens are twins?
Interestingly, even in the extremely rare event that kittens share the exact same genetic mark-up, this still does not necessarily mean that they share identical markings. Since the genes that code for color and markings can be expressed slightly differently depending on various factors, their appearance doesn’t have to match.
This means that it is very difficult to determine whether two kittens are identical twins in a genetic sense. In fact, the only way to be certain would be to perform a DNA test on each of them and compare the results.
How many kittens does a cat usually have?
Although female cats can get pregnant all year, the kittening season occurs during spring. Female cats come into season most often when the days are getting longer, so most litters are born in late spring. Female cats can even get pregnant while they are nursing a newborn litter, so it’s important to keep your cat inside at this time to avoid another pregnancy.
Litter size can vary dramatically in cats, ranging from one to twelve kittens and averaging at about four. The reason that litters are so big is that females 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 very different markings. Those that share similar markings may share the same father.
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.