Though you won't find dogs on the Jerry Springer Show conducting paternity tests, a single white pup in a whole litter of pitch-black pups may leave you scratching your head in disbelief. Your next thought goes out to Princess as you wonder if she was perhaps messing around with other dogs in the neighborhood. No need to employ a lie detector machine to have Princess confess; genetics may provide a reasonable explanation.
Unlike wolves, who are known to have annual breeding cycles and tend to be monogamous, female dogs tend to have bi-annual breeding cycles and seem to have no problem whatsoever in readily mating with multiple partners. This means that if you failed to closely supervise Princess while she was in heat, she may have mated with Rover the purebred golden retriever, Oscar the phlegmatic English bulldog and even Scruffy the stray mutt from around the corner.
What happens when Princess mates with multiple dogs? Simple, she gives life to a multi-sired litter, which simply means the pups have different fathers. This happens because female dogs produce several ova that remain available for fertilization for several days. To further ameliorate the process, male dogs produce sperm known for remaining well alive for up to eight days. Now add on top of that the polygamous behavioral components in domestic dogs, and you have the perfect recipe for a litter of pups that look quite different.
To Each His Own
You may wonder at some point if a puppy can have two fathers. The answer is no, but the litter can be sired by different fathers. In other words, a few puppies may be sired by one male and the rest may be sired by another. So if Princess was purposely mated with Beethoven the Saint Bernard, and then Scruffy the mutt secretly found a way to enter Princess's yard while she was out, about 63 days later she may give birth to a part purebred, part mixed-breed litter. Each pup will therefore have either Beethoven or Scruffy as a dad.
Don't be too quick to label your dog as a party gal; if her pups looks quite different from one another, chances are she just mated with just one lucky dog of a different breed. Geneticists call this process heterozygosis, which simply means you're dealing with a broad mixture of genetic variation. For instance, should your Saint Bernard mate with a Rottie, about 63 days later you may get some pups looking like Mama, others looking like Papa, and some with some mixed markings.
Seeking the Truth
Who's your daddy? If you're suspicious of your dog's mating behaviors and really need an answer, skip the lie-detecting machine and buy a DNA testing kit instead. This test will ultimately reveal if Princess had an affair with more than one dog. Also, by comparing the DNA of the pups with the DNA of the suspected fathers you can match up the puppy with his daddy. This way you can pinpoint the biological father of each pup, register the multi-sired litter if applicable and provide this proof to any potential buyers.
By Adrienne Farricelli
Responsible Dog: The Evolution and Domestication of the Dog
Psychology Today: Why Are Some Litter Pups Uniform in Appearance While Others Are Mismatched?
Ruckus Kennels: About Dual-Sired Breedings
American Kennel Club: Multi-Sired Litter Registration
About the Author
Adrienne Farricelli has been writing for magazines, books and online publications since 2005. She specializes in canine topics, previously working for the American Animal Hospital Association and receiving certification from the Certification Council for Professional Dog Trainers. Her articles have appeared in "USA Today," "The APDT Chronicle of the Dog" and "Every Dog Magazine." She also contributed a chapter in the book " Puppy Socialization - An Insider's Guide to Dog Behavioral Fitness" by Caryl Wolff.