Have you ever met a litter of young puppies who all looked so different it was hard to believe they were even related? Maybe a few of the puppies looked like Rottweilers and the others looked like Golden Retrievers. As it turns out, in a litter of puppies, some of the dogs can actually have different fathers, making them half siblings rather than full siblings. This phenomenon is called superfecundation.
First, what is superfecundation in dogs?

“Superfecundation occurs when a female mates with two or more males,” explains Donald Shellenberger, DVM, of VCA Smoketown Animal Hospital in Lancaster, Pennsylvania. “One litter can potentially have multiple fathers as long as they all mate with the female in the optimum time of conception.”
This means a litter might have two or even more fathers. This situation is often seen in stray animals, as well as in un-spayed females who live in close quarters with one or more intact male dogs. (In case you’re wondering, a single puppy cannot have multiple fathers; each individual puppy in a litter has only one father.)
“It’s probably more common in dogs than cats since cats ovulate with copulation,” Dr. Shellenberger says. “It can happen with other species, especially in animals with multiple eggs and large litter sizes.”
How does superfecundation in dogs happen?
Female dogs release many eggs when they are in heat (estrus, or the fertile period). If they copulate with more than one male dog within the two- to three-week estrus cycle, they can potentially become pregnant, perhaps by more than one male.
So, how can you tell if dogs have multiple fathers?

“You can tell if puppies in the same litter have different fathers by the characteristics, sizes and colors,” Dr. Shellenberger says.
The first tipoff is puppies who look drastically different from each other. Maybe some puppies are small and other puppies are large, or some pups are black and white with spots while other puppies are brindle.
Coat type can also be a clue: short coats for some puppies and long coats for others, or straight coats for some pups and curly coats for others. When the parents are mixed breeds, it can be harder to know, especially if you don’t know the predominant breeds in the mix.
In some cases, you might not be able to tell by appearance alone. This is especially true if the mom and all the probable fathers are all purebred of the same breed. In cases like this, a DNA test can reveal the true parentage (if only they had a Maury Show for dogs!).
How common is superfecundation in dogs?
Superfecundation happens more often than you might think. “In animals that are free to roam as they please, it’s fairly common,” Dr. Shellenberger explains.
Thumbnail: Photography ©amandafoundation.org | E+ / Getty Images.
6 thoughts on “Can a Litter of Dogs Have Different Fathers? Let’s Talk Dogs and Superfecundation”
my purebreed husky was stud by(2dogs) a purebreed husky and a mix breed dog . will there be a purebreed in the litter?
Does reserve litter breeding produce dogs with problems?
A black and white short haired looked like a pit bull mix lived across the street. ‘star’ had a litter she brought to my house 4 little black and white short haired and 2 brown, one brindled with one white ringed eye. I think Star was a bit neglected. She was a good dog but my Sophie the only female I’ve ever owned is by far the best dog I have ever had. I do know where 2 of the puppies went. The rest went to friends of a friend. I regret to say the mother ‘Star’ disappeared.
Actually that is not true a litter can have 2 fathers and each pup is duled sire it’s a practice in some breedings just saying
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I have a puppy from one of these litters… Officially, he is a papered, registerable, purebred Great Dane… Who looks like a Yellow Lab-Husky mix on steroids. The breeder still insists this is a purebred Dane, but everyone else in the world knows better.
(No, I didn’t pay for the puppy, or even get him on purpose. He’s a rescue; rejected by mom at 3 weeks, left to suffer and almost die by the breeder, who eventually handed the dying, 5 week old pup off to the first sucker… Me!)