Can Dogs Smell if Humans Are Related?

Can Dogs Smell if Humans Are Related

A lot’s been said about dog’s incredible sense of smell, including their ability to smell if humans are related. But just how true is this, though, and is it possible that dogs can smell family members?

The truth is dogs cannot smell if humans are related. To smell if humans were family members, dogs would need to be able smell and detect the existing DNA traces. While there’s no doubt that dogs have sophisticated smelling abilities, truth is, there isn’t tangible proof showing our canine pals can smell DNA.

That makes sense to me, but you also have to consider that people from the same household will have similar smells on them. Whether that’s cooking smells, detergents, and such like.

Based on that, it’s very possible that dogs can smell if you are family members who live in the same house together. But if a family member visited from another house, with different smells, the dog would not be able to smell the humans are related.

Can dogs smell DNA links?

No, dogs can’t smell DNA links. Research conducted in 2019 discovered this, which means dogs can’t smell if two people are related in laboratory conditions.

And if they can’t sniff out DNA links, then there’s no way they can smell human relatives.

On the flip side, though, dogs can recognize and tell family members apart through smell alone. Curious to know more about this? Keep reading for some juicy info!

If dogs can’t smell family members and human relatives, what can they do?

If there’s one thing we can’t dispute, it’s that our canine buddies possess “smelling superpowers”. They smell the weirdest and most extraordinary stuff, which our human noses can’t detect.

For example, dogs can detect dead bodies and even smell underwater!

Be it the natural chemicals in the breath of a diabetic person, the scent of fear-related chemicals on our skin pores, an incoming storm from miles away, every single ingredient in your favorite bag of cookies – you name it. We give them credit for sniffing out things that are odorless to us.

That’s probably why many assume there’s nothing under the sun that our “nosey” canine friends can’t sniff.

I’ve heard people say that what dogs can’t smell doesn’t exist. Put simply, they’re capable of smelling everything!  At least that’s what many dog lovers think.

But let’s separate the facts from the urban myths.

While it’s true that dogs have an astounding smelling ability, they can’t tell whether people are related just by their sense of smell.

But people do think this is the case. As an example, when a new baby comes into the home, some people will think the dog can smell it’s a family member. But this isn’t always the case, other dogs can become dangerously jealous of new babies, and won’t treat them like a member of the family!

can dogs smell human relatives
Dog will recognise and love their owner’s scent. But won’t be able to smell someone who is related to you.

Back to dogs smelling if humans are related though… as you probably know, people who are related have several DNA similarities. The DNA traces in their blood, hair follicles, saliva, and other cells in the body are almost the same.

So, for dogs to be able to smell that humans are relatives, they should be able to sniff out the genetic material in their bodies and make the conclusion.

But they can’t.

Reliable findings show that dogs cannot smell the genetic materials in our cells. Clearly, there’s a limit to what dogs can sniff out.

Our canine friends simply grow fond of people from the same household and learn to differentiate them by scent. The common belief is that a doggo knows people are related if it spends almost its entire time with the same faces.

Let’s just say that when dogs get used to being around the same people, they assume their favorite humans are related. It’s as simple as that.

How dogs tell family members apart

Are you aware that every person has a unique natural scent?

Yes, you read that right. We all have a signature odor. See how no one else in the world has the same fingerprints as you? That’s what your natural odor is like. It’s a genetically determined odor that lingers on our skin pores and clothes.

And when we sweat, even a little bit, this odor will be fully present in the sweat.  Think of this distinct scent as your unique identity. Not even identical twins have the same natural scent.

In fact, researchers from the Czech Republic did a mind-blowing study and found that well-trained dogs can differentiate a twin from another just by their natural odor.

Our noses and brains aren’t powerful enough to sniff and process another person’s natural odor. But you can already guess who can — our four-legged best friends.

So even during days when you aren’t all soaked up in your favorite perfume, your canine buddy can still sniff you from afar and know you’re around based on your natural scent.

As I’ve said a million times by now, dogs have impressive smelling abilities.

Their powerful olfactory system makes it possible for them to sniff the faintest of scents. Your doggo has millions of olfactory receptor cells in its nose lining. Approximately 300 million, to be precise.

In contrast, we only have around 6 million of these receptor cells.

Olfactory receptors enable our canine friends to smell all sorts of scents, including the almost-odorless natural scents our bodies emit. They don’t struggle like we do because their noses are up to the task.

When your dog is around a family member, their olfactory cells will smell the natural scent of this person. Remember, everyone in the family has their unique natural odor.

Here’s the most interesting part.

A dog’s nose and brain work together to determine what scent belongs to who.

The dog’s receptor cells will send the person’s odor information to the brain for processing. Similar to the human brain, our furry friends also have a part called the olfactory bulb in their brain. Its main function is processing people’s scents, among many other smells such as other dog’s butts.

The olfactory bulb in our canine pals is up to 40 times bigger than ours, so you can imagine the level of odor information processing that goes on in your pooch’s brain!

And once the olfactory bulb does its thing, the dog’s brain will store the family member’s scent as part of its olfactory memories. These as basically scent memories.

In other words, your furry friend’s brain will store every family member’s unique smell. Your pooch will know who owns what scent because it lingers in their brain.

How a dog’s brain responds to the familiar smell of a family member

Ever wondered what makes your beloved family pooch act super excited when around any of your family members?

Well, this is why.

Research shows your canine friend’s brain has another useful region called the caudate nucleus. The caudate is flooded with reward signals that get activated if something positive happens — For instance, when your pooch sees you handing them a treat, the caudate lights up with pleasure.

And when a dog smells a familiar family member, experts say the activation of the caudate is significantly higher. That means your dog’s brain will release more pleasure responses when they sniff the scent of a family member they know, hence the excitement.

You can train your dog to learn a relative’s scent, and they should remember it for many years. This is a good mental stimulation exercise and a great way to help your dog familiarize themselves with the smell of someone related to you (but doesn’t live with you, though they visit from time to time).

The good thing is, it only takes a few repetitions for our canine friends to master a new odor.  And the training process is quite straightforward:

  • First things first, get the scent sample. It can be a simple item like your relative’s favorite T-shirt. Make sure to hold this sample with a pair of gloves to avoid contaminating it with your scent.
  • Put the t-shirt in a small plastic bag and place it in an open room. Ensure you have a yummy treat in hand.
  • Have your dog on a leash and lead them to where this bag is. Bring them closer to it.
  • Immediately they begin sniffing the t-shirt, reward them with their high-value treat, and heap praises. With regular scent training sessions, your dog will eventually get accustomed to this target scent.

Related questions

Can dogs tell if your siblings?

The short answer is no since dogs can’t smell DNA traces to know whether two people are siblings.

Can dogs tell family members apart?

Yes, that’s right. Dogs use their powerful smelling ability to differentiate family members.

Can dogs smell DNA links?

No, they can’t. There’s currently no scientific evidence confirming dogs are capable of sniffing out DNA links.

Can dogs smell another person on you?

Yes, that’s correct. Dogs store any familiar scents in their brain. If there’s a new scent on you, they’ll know something’s off about your normal smell.


Whilst we might like to believe dogs can smell other human family members, it’s not strictly true. Yes, they will recognise the scent from a home, but not enough to make them realise people are related to each other.

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Marc Aaron

I write about the things we've learned about owning dogs, the adventures we have, and any advice and tips we've picked up along the way.

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