What Is the Runt of a Litter? (Find Out More) | 99PetCare
99PetCare > Dog Training & Behavior Articles > What Is the Runt of a Litter? (Find Out More)

What Is the Runt of a Litter? (Find Out More)

The term runtof the litter refers to the smallest (or sometimes weakest) puppy born in a litter. This is mostly in terms of size and weight. Runts often have health issues that will cause it to develop at a slower rate than the other puppies.

Litters usually only have one runt, although not all litters have runts. In the wild, runts are sometimes rejected, since its chances of survival are close to nil.

Luckily, we don’t live in the wild! With proper care, runts can grow up to be perfectly healthy.

Here's a good video showing the difference in size:

Is there always a runt?

Nope. Runts will not always be present in a litter. Even if a litter has dogs of different sizes, the smallest one does not necessarily become a runt. Even if smaller, it may be as healthy as and strong as the rest of the litter.

Why do litters have runts?

A dog’s uterus is Y-shaped, and the puppy that develops in the middle of the uterus is normally the farthest from the mothers blood supply and receives fewer nutrients.

So, in a sense, the puppy in the middle is “eating” less than the others, which leads to smaller size, less strength, and in some cases, even health problems.

What’s it like growing up as a runt of the litter?

At birth, a mama dog may reject a runt puppy and even refuse to break its amniotic sac (something that also happens, for example when puppies are born with deformities).

Because they’re smaller and weaker, runts are sometimes bullied by their siblings, who might shove them out of the way when it’s time to eat.

This is especially common in cases where the mother rejects the puppy, since it’s not getting enough food—and therefore not growing—which means it becomes even smaller and even weaker as time goes on.

This isn’t as much of a problem with human-bred dogs, but in the wild, it’s also difficult to runts to stay warm, since the bigger, stronger puppies nudge them out of the warmest spots.

The good news is that the opposite is also true: if the mama dog doesn’t reject her runt (or if a nice human feeds her), they can grow up to be just as big and playful as the other pooches in their litter.

The critical period for these tiny pups is usually 6-8 weeks. If they can tough it out until then, they’re usually on the road for a long, happy, healthy life.

Quick advice if you’re thinking of buying a runt…

If you’re thinking of buying a runt, it’s super important to get the little guy checked out with a vet. These puppies are usually much more likely to have health problems than their littermates—some of which may not been obvious.

That said, if your runt gets a clean bill of health, and you feed it plenty of good food, it can be just as awesome of a companion as any other pup.

Want to learn more? Here are some cool resources to check out:





Paul is an entrepreneur and marketer for the pet industry who works out of Chicago. He teaches people how to break free of the 9-to-5 grind by blogging for a living. Currently, Paul runs the 99PetCare along with the team of dedicated experts – so you know he has the knowledge to help you make the right choice.

Click Here to Leave a Comment Below 1 comments
Randy Crager - September 11, 2017

I was offered a pick of a litter of twelve Border Collies from a friend. It was obvious which was the runt but he wasn’t much smaller than the rest, probably slept while the others nursed. I was a runt when I was born, lol, but because of my condition I chose the runt. He was so easy to train and would obey my every command. If I told him to go out to the garage, he knew what I asked of him. He never even looked at a garbage bag, pale or garbage can and never ever begged for or looked at you if you ate food. When he needed to go out to take care of business he would lay by or set by the door and never whimpered for anything. He never ate more than one cup of dog food a day. he weighed his average Border Collie size of 60 pounds. so he grew out of his runt description. I’m 62 now and that was 35 years ago. sometimes I dream of going back in time and spending another day with him doing just anything. I sure miss Buddy my dog most times! I hope God has Buddy up there when I get there!


Our Comment Policy

Be kind. Ask questions. Discriminatory language, personal attacks, promotion, and spam
will be removed.

Leave a Reply:

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.