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Why Do Male Dogs Have Nipples?

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

Are nipples on male dogs just leftover parts from an embryonic developmental stage?

Are nipples on male dogs just leftover parts from an embryonic developmental stage?

So a friend of mine asked on social media if male dogs have nipples and someone commented: “If you need a dog with nipples just get a female.” I took up the commenter, and she asked me, “Why should a male dog have nipples?” Then another commenter wondered, "Why do human males have nipples?"

This sort of question can arise when people are not sure of things around them. In this article, we want to answer the question and discuss nipples in male dogs. For pet lovers, this is an interesting discussion to get you to know your best friend a little more!

Looking at most male mammals, one will notice that most of them have nipples with a few exceptions. You may be wondering why.

Dogs, as seen with most mammals, have male and female specimens equipped with nipples. The male pooch's nipples are seen lined neatly side-by-side running all through the length of its torso. If you observe carefully, it’s almost the same with their female folks. Yes, just like human males with breasts. So what's up with nipples on male dogs, and most of all, what in the world are they used for?

A commenter reasoned that perhaps our creator had some sort of mold made to manufacture different animals. Males and females must therefore have nipples because the same mold was used over and over in creating them before deciding on which one should be male or female based on the functions for each one in life.

Wow, what an argument. I want you to comment below on what you think about this line of reasoning!

Not only do male dogs have nipples, but their nipples also happen to have names; meaning so much work has been done biologically to pay attention to the male dog nipples, too. The nipples are in pairs like their female folks and, yup, they are named accordingly!

Many nipples, no known functions.

Many nipples, no known functions.

Trivia Question: How Many Nipples Do Dogs Have?

Here's a little piece of trivia for you: how many nipples do male dogs have? The number of nipples in male dogs tend to depend on the dog's overall size. Dogs may have eight or ten nipples which are called as follows:

For a ten-nippled dog, its nipples names will include:

  • Two cranial thoracic nipples
  • Two caudal thoracic nipples
  • Two cranial abdominal nipples
  • Two caudal abdominal nipples
  • Two pairs of inguinal nipples
There is no clear purpose for the existence of nipples in male dogs.

There is no clear purpose for the existence of nipples in male dogs.

Nipples as Decoration?

Why would someone create a feature not useful in a product? Sometimes it's best not to go on social media if you don’t want to get some funny ideas in your head with the kind of questions people ask… Why would a male have nipples that do not produce milk to feed its young like the females? Well, this is a very good question.

"Nipples in male dogs are only a decoration," suggested a commenter. Well, it's not like male dogs like to put piercings on them, so the word decorative is a bit off as it reminds me of Christmas trees, but hey, that's what he said.

Turns out, there is really no explanation for their use; some suggest male and female animals were given default factory settings, so to speak. The cookie mold to form dogs must have not been gender-sensitive.

The dogs who got lucky to have female functions are blessed with nipples producing milk, but ones with male functions end up with a dry land under their belly. Nipples in male dogs are therefore destined to remain in what's known as a "rudimentary state." To put it bluntly, they are just buttons with no known function.

A Big Pile of Dough?

Let's take a bit of a step back though, shall we? A trip back into the womb, when puppies are in their embryonic state just floating about, shows us that nipples are already there in both female and male fetuses during their development. Just as one of the commenters said, pups being male or female are virtually the same as if they were actually taken from a big pile of dough and cut out into shapes by using the same exact mold.

By the way, for those skpetics out there, this is all backed up by claims by veterinarian Dr. Justin Lee who explains in his book, It's a Dog's Life...but It's Your Carpet, how pups are basically made all the same in utero, until later on when powerful sex hormones kick in and start morphing them using a process known as "sexual differentiation." It is therefore only later in life that female sex hormones start taking off, making male dogs and female dogs different.

In females, the hormones responsible for nipple changes reach their peak levels when the female dog gets pregnant and is just about getting ready to whelp or is undergoing what's known as a false pregnancy. These surges in hormones are what trigger nipple enlargement and the production of milk.

So there you have it, a biological explanation as to why female dogs have nipples. However, this does not explain the existence of male nipples. Of course, the female nipples have a defined function, but male nipples do not. Yet, it seems that Mother Nature must still feel they must have some purpose, otherwise one would assume that adaptive pressure would have wiped them out.

If you love dogs, why not join in this interesting discussion about why male dogs have nipples? Take the time to examine your male dog's nipples and tell us what you think? Do your male dog’s nipples produce milk? Hopefully not, but keep me posted about your findings!

© 2016 Adrienne Farricelli

Comments

Adrienne Farricelli (author) on December 27, 2016:

Hi DzyMsLizzy, this is so interesting, thank you for sharing your thoughts. I now recall a while back hearing some story about a man nursing s child but can't recall if it was fact or fiction or something that appeared on an episode of Ripley's Believe it or Not. Any how, this could be an explanation as to why Mother Nature has preserved nipples in men. Perhaps they are meant to be used as a reservoir in case there would ever be a shortage of milk! Mother Nature knows best.

Liz Elias from Oakley, CA on December 27, 2016:

Well, very interesting! Funny, but I clicked onto this article because I happen to own a book with a similar name, "Why do Men Have Nipples?"

It addresses that, and many other crazy questions, such as, 'do fish sleep?'

In the human, while male nipples are basically considered non-functional, (and the explanation for their presence is the same as you have explained), they CAN actually lactate and feed a child, IF appropriately stimulated.

Even in females, it is the suckling of the baby that causes the demand for milk production to start. In the first couple of days after birth, the only fluid produced is colostrum, which mainly consists of antibodies present in the mother. It kick-starts the child's immune system.

Male babies are also sometimes born with, or show soon after birth, to produce this liquid. This is believed to be a function of the mother's pregnancy hormones. However, that it sometimes happens, illustrates the fact that the 'factory' is there, lying unused for the majority of men all their lives.

I found it very interesting indeed.

Superstitions people of the olden days called it "witches' milk" when a male infant displayed this apparent anomaly.

Well written article!