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This Is Why Your Dog Has 9 Nipples (+ What It Means)

Why Does My Dog Have 9 Nipples

Your dog gets on their back. 

They’re looking at you expectantly. So they’re not playing dead. 

The universal translation for this is, “Hooman! Rub my belly!”

You happily oblige. But as you do, you notice something odd. And not just the synonym for weird. It’s really odd.

You inspect your dog more closely. “Two. Four. Six. Eight. . . Nine.” 

Definitely 9 nipples.

But nipples come in pairs. Right? Why is there a lone nipple?

Keep reading to discover:

  • Why your dog has 9 nipples.
  • If there are any health implications.
  • What it means for your dog and their pups.
  • Interesting facts about a dog’s number of nipples.
  • And so much more…

Why does my dog have 9 nipples? 

Your dog has 9 nipples as a result of a glitch in a process during embryonic development. Dogs typically have an even number of nipples – 8 to 10. Having 9 nipples may be a minor birth defect similar to the one in humans where the development of a 3rd nipple is termed “supernumerary nipple.”

Is it weird that my dog has 9 nipples?

The average dog has an even number of nipples.

So yes, it’s weird that your dog has 9 of them. But don’t take it the wrong way. Weird is not necessarily bad. While it may be atypical, it doesn’t make your dog a freak.

Friends or random dog lovers at the park may want to give your good boy or good girl a belly rub. Don’t worry about them noticing that extra nipple. 

“Hold it! Did you say my good boy?”

Indeed! Your good four-legged boy has “man boobs.” Just as male humans, male dogs have nipples too. These have no function but are very much present. 

Regardless of your dog’s sex, that odd nipple is not a cause for embarrassment. On the contrary, it’s something you might even want to point out yourself. 

Dogs of all breeds share countless traits. If you have one of the rare pooches with this feature, be proud of it! It sets your dog apart from most of the others.

And as far as weirdness goes, the number is all there is to it. 

There’s no bearing on health. So go on and heave that sigh of relief. Dogs with 9 nipples are neither more nor less prone to illnesses relating to nipples. 

The Merck Vet Manual identifies 2 examples of these: 

Mammary tumors and mastitis

Dog Has 9 Nipples Due To Mammary Tumors And Mastitis

Mammary glands are responsible for milk production. And all animals with mammary glands can have breast cancer. That includes dogs. 

It may sound strange at first. 

“Isn’t that a human thing?”

But among domestic species, dogs are the most affected by mammary tumors. Even 3 times more than women. So it’s not a very human thing after all.

And sadly, about 45% of canine mammary tumors are malignant. This means they are cancerous. 

Dogs may also suffer from a bacterial infection known as mastitis. This happens when the mammary glands become inflamed after giving birth. 

But their nipples will become enlarged as well if they’re pregnant. And they’ll show a nesting behavior too.

Risk factors for mastitis include:

  • Poor sanitary conditions.
  • Trauma inflicted by offspring.
  • Whole-body infection.

But these illnesses may beset a dog regardless of how many nipples they have, whether even or odd.

As to an obvious disadvantage of having 9 nipples, it’s nursing 10 or more pups. But other than that, there are no drawbacks nor benefits. 

In short, – yes, 9 nipples is weird. But all things considered, your dog is as normal as they come. 

Reading tip: Why Do Dogs Hump The Air? 9 Real Causes + What To Do

How many nipples should a dog have?

On average, dogs have 8 to 10 nipples. Smaller breeds such as Chihuahuas can have 6. They are found in pairs along 2 symmetrical rows from the groin to the abdomen. 

However, some dogs have an odd number of 7 or 9 nipples. 

Depending on how you look at it, that’s one nipple more or less.

An odd number of nipples on a dog is unusual. So naturally, lots of fur parents share their discovery of this on dog forums. 

They express their surprise and amusement. But the banter comes with more serious questions.

Dog owners are concerned about what it means for their dog. They also have a burning curiosity about how their dog ended up with an odd number of nipples in the first place. 

And, of course, they want to know how many nipples a dog should have. Owners of dogs with even-numbered nipples wonder about this too.

But unfortunately for both sets of owners, they cannot find a thorough answer in the threads.

Let’s tackle this now.

Dogs are altricial animals. This means that they are born fully dependent on their mothers. Most importantly for sustenance. Milk is crucial to their survival. They have access to it through the nipples. 

In mammals, the general number of nipples depends on how many offspring they can carry in their womb. 

For example, cats usually have 8 nipples as they can have several kittens in a litter. 

Elephants and primates have only 2 nipples as they normally give birth to only 1 or 2 babies at a time. 

In the same way, dogs should have 6 to 10 nipples because they produce around that number of young in a litter. 

While it’s not strictly a 1 nipple is to 1 puppy ratio, the number of pups is roughly that of the nipples. This serves the obvious purpose of ensuring that every pup gets to suckle.

A study published in Ethology investigated the suckling behavior of domestic dogs. 10 litters consisting of 47 puppies were observed. Similarities were prevalent in the findings across all the litters.

The young pigs and cats have shown “teat consistency.” This means they primarily use 1 or 2 nipples in particular. 

But according to the study, the puppies had weak preferences. They generally went for any nipple.

This potentially meant more chaos and jockeying since there were no “pre-assigned” nipples. But surprisingly, very little agonistic behavior was displayed within a litter.

Agonistic Behavior or Agonism is defined by Encyclopaedia Britannica as, “survivalist animal behavior that includes aggression, defense, and avoidance.”

To put it simply, animals act aggressively when competing for resources such as food or a mate.

It is commonly believed that puppies begin demonstrating dominance as they wrestle for their share of milk. But the findings of this study are undoing that theory. 

The researchers also found that puppies in a litter didn’t all suckle at the same time. While some suckled, some slept and others played. 

Those who fancy the idea of dominance among puppies may argue that this is the reason for the lack of agonistic behavior found in the study.

Less puppies suckling at a given time eliminates the need to jockey for a nipple. 


But it further underlines why a dog should have that average number of 8 to 10 nipples. A nursing mother should be able to accommodate all her pups.

People also ask:

What does the number of nipples on a dog mean?

The number of nipples on a dog roughly corresponds to the number of puppies they can deliver. This is determined by their breed.

According to the AKC, a normal litter can consist of 1 to 12 puppies. A litter of 5 to 6 puppies is considered the average for all dogs in general.

Large breeds have bigger litters. Their body size allows for safer gestation and delivery of more puppies. And naturally, more nipples are required. 

Small breeds have smaller litters and therefore don’t need as many nipples.

Let’s take as an example German Shepherds and Golden Retrievers. Both are large breeds and have an average litter of 8 puppies. 

With smaller breeds, the litter size and number of nipples become less.

A Standard Poodle has an average litter size of 7. Miniature Poodles average 5 puppies a litter, while Toy Poodles average a mere 3.

Yorkshire Terriers and Chihuahuas are estimated to have a litter size of only 2 to 5. 

There’s no logical need for more nipples. And there’s not that much space on their bodies for more either. 

An old belief states that the number of nipples a dog has indicates how many puppies they will give birth to. Therefore, 8 nipples equal a litter of 8 pups. But this math is a myth.

Dogs can have less nipples and more pups, or more nipples and less pups. 

There’s no way of accurately predicting how many puppies there will be in a litter. 

According to the OVRS, certain factors can influence the litter size:

  • Breed.
  • Genetics.
  • Nutrition.
  • Age of the dam (mother).
  • Age of the sire (father).
  • Time of the year (litters born in spring are generally larger). 

But none of the above will tell you the exact number of puppies to expect.

It has been recognized that certain dog breeds have a given average number of puppies in a litter. But even that is not consistent. 

For example, a Rottweiler is a large breed with an average litter size of 8. They can have as many as 12 puppies. But a first-time Rottweiler mother may have only 2.

German Shorthaired Pointers have an average litter of 9 puppies. But they can have either small or large litters. 

Dachshunds average 5 puppies a litter. But they can have as few as 1 pup. They can also have more than 6. It entirely depends on the size of the particular Dachshund. 

Beagles can range from 1 to 10 puppies a litter. And if a Beagle has a large litter, their next ones will also be large. Likewise, if they have a small litter, the next ones will also be small. 

But a Bulldog litter is the easiest to predict. They will have either 3 or 4 puppies. 

Clearly, there is nothing specific nor consistent when it comes to puppy litters. But the number of nipples a dog has gives a general idea of how many puppies they can have. 

This hint should be enough to satisfy the eager fur parents who want to level up to fur grandparents.

Why does my dog have an odd number of nipples?

Your dog may have an odd number of nipples as a result of certain processes during their embryonic development. 

It’s been established that an even number of nipples is the norm for dogs of all breeds. But some dogs are oddities (pun intended) and deviate from that standard. 

These dogs have either 7 or 9 nipples.

Interestingly enough, dogs are not alone in this peculiarity. 

It’s often said that dogs are a man’s best friend. Best friends should have a lot in common. But who would have guessed that having an odd number of nipples could be a mutual trait?

When humans have an odd number of nipples, it’s usually 3. Although there can be more. 

The term for this condition is “supernumerary nipple.” 

GARD identifies it as a “common, minor birth defect.”

There are areas of the body known as “milk lines” or “mammary lines” where the breast tissue appears. 

These lines start out as 2 strips of slightly thickened ectoderm tissue. It happens during the 4th week of human embryonic development. 

The mammary lines extend from the armpits downwards across the chest and abdomen. They reach all the way to the region of the upper thighs near the groin. 

These strips continue to thicken even further. Finally, they become what is known as “mammary ridges.”

These ridges remain thick in the area where the normal pair of nipples develop. The rest of the thickened tissue usually softens up to become regular ectoderm tissue once more – but sometimes it doesn’t. 

Some of the mammary ridges remain thick. And nipples, unusually and numerically odd, may develop on them. 

“Enough about humans! What does it have to do with my dog?”

While the term “supernumerary nipple” isn’t used to refer to 7 or 9 nipples in dogs, it technically means the same thing as an extra nipple in humans. 

Where dogs should have an even number of 6 or 8 nipples, they have 7 or 9 instead. 

One more.


It’s plausible that this extends beyond a shared technical definition. 

Perhaps it could also be an identical scientific explanation for the development of your dog’s odd nipple.