Superfecundation: Yes, Kittens and Pups From the Same Litter Can Have Different Dads

You can bet that cats and dogs don’t like The Maury Povich Show! — because paternity tests won’t seem like a big deal to them. If you’re a pet owner whose furry ones just happened to birth a handful of kits or pups whose fur coats just don’t add up, then your best guess is that it's because of superfecundation! It’s a mouthful to pronounce, for sure. But it’s the phenomenon where kits and pups from the same litter can have different dads!

If the word still confuses you, here are the answers to the questions you might be asking:

How is it even possible that the kits and pups from the same litter can have different dads?

When mammals like cats and dogs get pregnant, most of the time, we can expect more than one puppy or kitten to come out of their moms. That’s because with cats, when the unspayed ones are in heat — which occurs every 2-3 weeks — they can release multiple eggs; with an average of four per heat cycle. With dogs, the female ones can go into heat usually every 6 months.

Whenever these unspayed fluffy ones go into heat, you can guarantee that the male cats and dogs will “simp” for the girls. And they’ll have no problem professing their love by trying to, ahem, hump the gals with the goal of impregnating them. But little do they know (or they probably do, they just don’t care!) that there are others who are just like them — doing the exact same thing with their exact same SO! Thus, it’s very possible that tom cat #1 or stud #1 can fertilize egg #1 — and the other tom cats and studs will fertilize the other eggs that their queen releases! — to each (egg) their own!

Is superfecundation applicable to humans?

It is extremely rare that a human woman will give birth to 6-8 kids per pregnancy! In fact, it’s considered somewhat unusual when a soon-to-be mom conceives twins. That’s because in most cases, women only release 1 egg per ovulation (aka the human version of being in heat!). But there are those relatively rare occasions when a woman releases more than one — and that’s why there are sometimes twins!

However, when a woman does indeed release more than one egg, and they have more than one sexual partner, it’s possible that two different sperm cells can fertilize the two different eggs that were released. Because these eggs can release in one ovulation period, the two fertilized eggs will eventually turn into a zygote, develop, turn into fetuses — and the whole fetal development where the little bean turns into a full-blown tiny human.

Therefore, when two fetuses develop at the same time in one uterus — and come out at the same time — they’re, of course, considered twins. When one egg is fertilized and this egg then splits in two, to create two separate embryos, we speak of identical twins. When, on the other hand two eggs are fertilized at the same time by two different sperm (from the same or two different males), we speak of fraternal twins. And yes, it’s possible the babies could have different dads. 

So, superfecundation is indeed possible for humans — but it’s an extremely rare occurrence!

Is it just cats and dogs who can possibly have different baby daddies?

Superfecundation isn’t exclusive to cats, dogs, and — sometimes — humans. Plenty of other animals can have different dads even though they’re from the same litter! It has been observed among horses, cows, sheep, rodents like mice and rats, rabbits, kangaroos, and many other animals.

Unlike humans, other animals don’t fight about paternity test results — it’s instinct for the females to entertain as many guys as they can for the purpose of reproduction and, ultimately, the preservation of the species. It’s believed that the reason they feel the need to mate is to spread their genes — for survival's sake and so they’ll prevent their species from extinction.

That’s why, sadly, if animals do go extinct — despite their innate and biological need to reproduce — there’s a chance that outside factors like human intervention (or destruction) had something to do with it. But that’s not always the case. Extreme climate conditions like the ice age and natural disasters like asteroid impacts can also contribute to the extinction of certain animals — like the dinosaurs and Saber-toothed cats!

Superfecundation: It’s Not a Mary Poppins Song!

If you find it odd that animals like kittens and pups from the same litter can have different dads, know that there are also cases of superfecundation in other animals — and even humans! It may be difficult to grasp, but, because — because, well, nature!