6 Unbelievable Things Dogs Can Smell That Humans Cannot

Unbelievable Things Dogs Can Smell

(that you can’t)

I’m sure you already know some things about a dog’s incredible sense of smell, but I wonder if you realize all the things dogs can smell that are way beyond the scope of our human ability.Unbelievable Things Dogs Can Smell That Humans Cannot

A dog’s brain is specialized for identifying scents, and canines rely on their sense of smell to interpret their world much like we use our sight to interpret ours. The percentage of the dog’s brain that is devoted to analyzing smells is actually 40 times larger than that of a human! It’s been estimated that dogs can identify smells somewhere between 1,000 to 10,000 times better than humans can.

Inside a Dog’s Nose

There are up to 300 million olfactory receptors in a dog’s nose, allowing them to detect odors in parts per trillion.  Compare that to a mere 5 million receptors in the human nose, with the ability to detect orders in parts per billion.  The dog’s sense of smell is thought to be 10,000 to 100,000 times more acute than ours.

Table: Scent-Detecting Cells in People and Dog Breeds

SpeciesNumber of Scent Receptors
Humans5 million
Dachshund125 million
Fox Terrier147 million
Beagle225 million
German Shepherd225 million
Bloodhound300 million

Source:  Understanding a Dog’s Sense of Smell

Unbelievable Things Dogs Can Smell That Humans Cannot

Some Unbelievable Things Dogs Can Smell (that humans can’t)

1.  Cancer

Dogs trained to detect cancer have an accuracy rate between 88 and 97% versus machines, which is between 85 and 90%., by simply sniffing the a breath, urine, or blood sample.

2.  Epilepsy

Seizure Alert Dogs can warn a person of an oncoming epilepsy attack anywhere from 15 minutes to 12 hours before. Some are trained to guard the owner, keeping them away from stairs, while others are trained to press a button on a phone to dial emergency services.

3.  Computer Gear

Yes, computer gear, such as hard drives and other digital devices.  These specially trained dogs are being used to find evidence child pornographers and other cyber criminals may have hidden away.  (You can run, but you can’t hide.)

4.  Ovulation

Some dogs are trained to smell cow urine to detect when a cow is in heat to help farmers know when to use artificial insemination.

5.  Bed bugs

Dogs can detect bed bug infestations with a reported 96 percent accuracy

6.  Emotions

Dogs can smell changes in your hormones and body chemicals, thereby detecting your emotions, which explains how they know when you’re feeling sad, fearful, or ill.

Another Fun Fact – Your Dog’s Noseprint

Your dog’s nose has a pattern of ridges and dimples that, in combination with the outline of its nostril openings, make up a nose print believed to be as individual and unique as a human being’s fingerprints. Companies even register nose prints as a way of identifying and helping to locate lost or stolen dogs, a system that is now being used by kennel clubs around the world.

Incidently, it’s the same with cats, as you can read in my article, “Cat Nose Prints as Unique as Human Fingerprints.  Cats also have a great sense of smell, but not as crazy as a dog’s.

Unbelievable Things Dogs Can Smell That Humans Cannot

Unbelievable Things Dogs Can Smell That Humans Cannot


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32 thoughts on “6 Unbelievable Things Dogs Can Smell That Humans Cannot”

  1. another reason to have a dog
    1. they can be a mans best friend and
    2. they can dial emergency in case your having a heart attack

  2. I never knew about the dogs noseprint being like our fingerprints. I would have never thought about computer equipment being something they could find.

  3. Yes, dogs are amazing! But, I sure didn’t know of these things they can smell! That is awesome! I want to learn more about the hearing of dogs, especially Yorkies. My YorkiePoo has always been much morre sensitive to hearing than all of my daughter’s dogs and the dogs I had in the past. He starts barking first! Thanks for sharing this!

  4. Dogs are such helpful creatures!

    Despite their super-smelling abilities, I find that dogs seem to spend a hilarious amount of time finding bits of food that bounce off their nose or land on their back.

    With that, I’m sure we’ll always find more ways to utilize their talents.

  5. This is such an interesting post! I work with a rescue so always have foster dogs coming in and out and notice how every single one of them have very strong sense of smell.

    • I’m glad you enjoy learning about animals, Jennifer. Makes me want to share even more when people tell me that. I’m happy that you like my pics too. I try to find the funnest ones. Thanks for reading my post!

  6. I never knew dogs could smell computer devices. It’s so amazing that their sense of smell is so good and they can be trained to help us. 🙂

    • I never would have even thought that digital equipment had an odor, to begin with. They truly have an amazing sense of smell. Wow. Thanks for taking the time to read my blog, Jan. I appreciate you.

  7. I’ve heard of a few of these (cancer, for example) but not the others.

    my mom has Alzheimer’s and whenever one of the siblings takes one of our dogs to visit her, they crawl up in her lap and rest there. She’s a dog person and loves it and they seem to sense her need for comfort. It’s always heart rending. after reading this, I wonder if they’re smelling something we can’t. Interesting thought.

    • Dogs are so good with people that have Alzheimer’s. I used to work with hospice and dogs have shown me shown me so many things. I once brought my dog to one client’s house. THe couple had been married over 60 years and the husband no longer knew who his wife was. He never spoke, never reacted to anything. Until the day I brought my dog to see him. He reached out for my dog and she laid with him, where he continued to pet her. His wife was so moved by this. Dogs truly are awesome.

      I’m sorry to hear about your Mom. My mother has Alzheimer’s too. It’s a very sad disease. Peace to you and your family.


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