We Asked Veterinarians: Why Do Dogs Like Period Blood?

curious mixed breed dog sniffing

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Picture of <a href="https://notabully.org/author/joseph-menicucci-dvm" target="_blank" rel="noopener">     <span style="font-size: 21px; color: black;"></span>     <strong style="font-size: 20px; color: black;">Dr. Joseph Menicucci, DVM </strong> </a>

Dr. Menicucci is a Colorado-based veterinarian with well over a decade of clinical experience.

Picture of <a href="https://notabully.org/author/dr-nita-patel" target="_blank" rel="noopener">     <span style="font-size: 21px; color: black;"></span>     <strong style="font-size: 20px; color: black;">Dr. Nita Vasudevan Patel, DVM, MS</strong> </a>

Dr. Patel is a Florida-based veterinarian with over half a decade of experience.

It’s no secret that our pups occasionally engage in behaviors that might seem peculiar or even off-putting to us. But one of the most surprising canine interests is period blood, and while this can be a sensitive topic for many it’s something that we’re frequently asked about. Here’s a recent question from a Not A Bully reader named Ann:

“Why does my puppy seem so interested in my menstrual blood? We’ve only had him for a few weeks and he hasn’t shown any interest in the bathroom trash (so we left it on the ground). But then my boyfriend came into the bathroom to see my dog sniffing and licking a used menstrual pad in the trash. Is this normal? Should I be worried?”

As a veterinary technician, I can tell you this is completely normal! But also talked to Not A Bully’s advising veterinarians Dr. Patel and Dr. Menicucci to come up with a quick answer:

Dogs are naturally drawn to period blood due to its unique smell and the potential hormonal information it provides.

While it might seem odd, it’s a common instinctual behavior. Dogs, especially those bred for hunting, may find the scent particularly intriguing due to their acute sense of smell. This behavior is not usually a cause for concern, but it’s important to prevent dogs from ingesting menstrual products, which can be extremely dangerous.

Training commands like “leave it” can help manage this behavior. Keeping the bathroom door closed and trash bins secure can also prevent unwanted access to menstrual products.

In this article, we’ll take a closer look at each explanation for a deeper understanding of the biological and instinctual motivations for this behavior. Let’s get started!

Reason 1: Period Blood Smells Unusual and Dogs Like Unusual Scents

Period blood is not just plain blood.  It’s a complex mix of body fluid made up of blood, secretions, and skin cells of a woman’s uterine wall.

As a result, period blood smells different from typical blood, even to our human noses. And if we can smell the difference between blood and period blood, imagine what a dog’s powerful nose can detect!

Period blood is something that dogs aren’t able to smell regularly and could be something worth investigating.  Dogs like to smell unusual things in the same way that we humans might like to read new books.  An unusual smell gives a dog a sense of mental stimulation and enrichment.

So, it’s natural for a dog to show interest in new smells and it’s not just menstrual blood that will pique your pup’s interest.

Dr. Menicucci explains that “dogs’ attraction to various scents, including menstrual blood, is instinctual and linked to their scavenging behavior. However, this does not mean dogs have a specific preference for blood over other scents and the scavenging instinct encourages them to explore any new scent.”

Reason 2: They Might Be Smelling Some Hormonal Changes In You

Dogs have such amazing senses of smell that they can detect hormone fluctuations simply by the changes in smell that they create.

Many owners report changes in their dog’s behavior once they become pregnant.  Some dogs will lie their heads on their owners’ stomachs or become more protective. This is likely a response to their perception of changing hormones.

For dogs, period blood can hold a plethora of information about their owner’s hormones.  Dogs might like to smell your period blood because it gives them information about your health. One study found that dogs can detect changes in their owner’s stress levels simply by scent.

Just as a dog takes an interest in the unique smell of menstrual blood, the cascade of hormonal changes generates other smells that dogs are also interested in exploring.

Reason 3: You Have A “Blood” Breed

If you have a dog that was originally bred for hunting, chances are they’ll like your period blood more than another dog breed would. The average dog has a sense of smell that’s 100 times better than a human’s and a bloodhound’s sense of smell is 300 times better than a human’s.

Still, this is likely only a minor factor, and Dr. Menicucci points out that “While certain breeds have heightened scent-tracking abilities, an attraction to period blood is not specific to hunting breeds. All dogs have a strong sense of smell that could lead to an interest in menstrual blood and the associated hormonal changes.”

Reason 4: They’re Simply Curious

Dogs are innately curious animals and Dr. Menicucci explains that “Dogs explore their environment through their sense of smell, and new scents naturally pique their curiosity.”  If a new scent comes onto their arena, they’re going to want to investigate!

They’re Probably Not Checking On Your Health

One of the more common answers we found was an explanation that dogs are worried about the health of whoever they’re sniffing. While it’s possible, it’s unlikely. Dr. Menicucci explains that “While dogs are attuned to their owners, interpreting an interest in menstrual blood as a concern might be anthropomorphizing too much. It’s much more likely that dogs are just investigating a new scent and more motivated by curiosity and instinct rather than concern.”

Should You Worry If Your Dog Likes Period Blood?

If your dog likes period blood, it’s not necessarily a reason to be concerned.  This is a pretty natural response to an interesting smell and something that many dogs are fascinated by.

In theory, it’s not technically bad for a dog to lick period blood once.  The safest option is to keep your dog from licking period blood at all. Some dogs might like the smell of blood so much that they ingest feminine hygiene products. Or, other dogs might like the smell so much that they can’t help but sniff inappropriately at people who are on their periods.

What If Your Dog Ingests A Feminine Hygiene Product?

If you are a dog in just a used tampon or pad, you’ll need to call a veterinarian right away.   These products can be dangerous when ingested because they often expand in size as they become wet. This has the potential to cause serious gastrointestinal complications, or even become fatal to your dog.  If your dog ingests a feminine product, it must be addressed immediately as the situation can quickly become life-threatening for your dog.

How To Keep Your Dog From Sniffing Period Blood

There are a few simple ways to keep your dog from obsessing over period blood and running a risk of ingesting something.  Keep reading to find out recommendations for a dog who likes the smell of period blood a little too much.

Keep The Bathroom Door Closed and the Trashcans Empty

One way to keep dogs from period blood is to make sure that bathroom doors always stay closed or that trash is emptied constantly while someone in the house is menstruating.  This solves the problem of a dog getting too curious about used products that have been thrown away.

Unfortunately, this method won’t keep your period-loving dog from sniffing at strangers’ crotches!

Train Them To “Leave It”

Training your dog to “leave it” is really the only way to keep them from sniffing at people on their periods.

If your dog likes period blood, they’re bound to get a little too close to strangers from time to time.  Teaching your dog to leave it is a valuable tool that can be applied to many areas of your dog’s life.  Training leave it will take time and patience and you may need to enlist a professional dog trainer to help.  The video below gives you some great tips to help get you started.

Final Thoughts

It’s kind of strange to think that dogs actually like period blood.  It feels weird and gross.

However, it makes perfect sense when you look at things from a biological standpoint. Dogs like the smell of period blood because it smells different and hormonal.  Dogs can be curious and even worried about their owners while they’re on their periods.  Plus, all dogs are instinctually attracted to period blood and some hunting breeds are especially keen on it.

Whatever the reason is that your dog likes period blood, you should always try to keep them from ingesting blood or used hygiene products!

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