7 Amazing Facts About Your Dog's Sense of Smell

Science is learning all kinds of things about dogs' noses, including this: Humans are splendidly, amazingly stinky to dogs, and they love us for it.

People have known for millennia that dogs sense the world in a very different way than we do. But science has recently learned all kinds of wow-worthy info about our dogs' olfaction. Check out seven of latest, greatest findings about dogs' remarkable sniffers.

Dog nose closeup by Shutterstock

1. Dogs smell way better than we do

Yeah, you can read that two ways, but think back to what your dog smells like when wet, and you'll figure out the right meaning. When it comes to nose sensitivity, dogs are the paws-down winners over humans. Numbers abound about how much better a dog’s sense of smell is than ours. There are so many variables that it’s almost impossible to quantify. I’ve seen figures indicating that it’s from 10 to 100 to 1,000 to 1,000,000 times better. Scientists I've spoken with say that dogs can detect some, if not most, odors at concentrations of parts per trillion.
Psychologist and prolific dog book author Stanley Coren gave me an example of what that huge sniffer sensitivity looks like. Let’s say you have a gram of a component of human sweat known as butyric acid. Surprisingly, humans are quite good at smelling this. If you let it evaporate in the space of a 10-story building, many of us would still be able to detect a faint scent upon entering the building. Not bad, for a human nose. But consider this: If you put the 135-square-mile city of Philadelphia under a 300-foot-high enclosure, evaporated the gram of butyric acid and let a dog in, the average dog would still be able to detect the odor.

Nectar of the gods! Pup smelling boot by Shutterstock

2. To a dog, you reek

As clean as you are, and as much soap and perfume and deodorant you wear, you are still splendidly stinky to your dog. Every human has a unique scent fingerprint, and that's pretty much everything a dog needs to tell one person from another. "To our dogs, we are our scent," says canine cognition expert Alexandra Horowitz, author of the enlightening book, Inside of a Dog: What Dogs See, Smell, and Know. In that book, she writes this wonderful description:
"Humans stink. The human armpit is one of the most profound sources of odor produced by any animal; our breath is a confusing melody of smells; our genitals reek. The organ that covers our body –- our skin -- is itself covered in sweat and sebaceous glands, which are regularly churning out fluid and oils holding our particular brand of scent. When we touch objects, we leave a bit of ourselves on them; a slough of skin, with its clutch of bacteria steadily munching and excreting away. This is our smell, our signature odor."

No matter how much you may try to disguise it, you smell bigtime, at least to your dog! Dog sniffing among people by Shutterstock

3. We're like Pigpen

With every step you take, you shed loads of skin flakes -- kind of like the Peanuts character Pigpen and his ubiquitous dirt cloud. Real people have the same billow, only it’s made up of skin cells, which, when in this flake form, are known as rafts, or scurf. Get this: We shed 50 million skin cells each minute. Wow! “They fall like microscopic snowflakes,” Coren says. I am sitting here only moving my fingers on my keyboard because I really don't want to shed, but no matter what I do, I'm just a snowstorm. Thankfully, we can’t see this winter wonderland ourselves. But these rafts and scurf, with their biological richness, including the bacteria that sheds with them, are very “visible” to dogs’ noses.

4. You can't fool your dog

Research indicates that it’s quite likely that dogs can smell fear, anxiety, even sadness. The flight-or-fight hormone, adrenaline, is undetectable by our noses, but dogs can apparently smell it. In addition, fear or anxiety is often accompanied by increased heart rate and blood flow, which sends telltale body chemicals more quickly to the skin surface. Trying to mask your strong feelings with a casual smile may fool your friends, but it's not going to fool your best friend.

5. Dogs send "pee-mail"

I love this description of dog communiques from Coren: “Dogs read about the world through their noses, and they write their messages, at least to other dogs, in their urine." It's tempting to drag your dog along on a walk when he's sniffing everything annoyingly slowly, but give him chance to read the neighborhood gossip column, and let him do a little writing while he's at it.

6. The truth about nether regions

When dogs start sniffing each other's nether regions, chances are they're learning far more about each other than you and the other dog's owner are learning through idle chitchat. Exactly what the dogs are learning, and what they do with that information, has yet to be figured out by science. But it’s very likely far beyond “Nice weather we’re having, eh?” It’s probably more along the lines of, "Oh, you're a nice dog, and you had chicken recently, and you're about, um, 10 years old?"

Greetings sometimes start face to face, but quickly end up on the other end of the dog, where there's loads of info for the sniffing. Dogs sniffing each other by Shutterstock

7. Scientists are studying dogs' noses as never before

Maybe it's because of dogs' role in the military as incomparable IED detectors.  Or maybe it's that dog noses are just so amazing, and the more we know, the more we want to know. Canine sniffing ability is being studied more than ever at universities around the world. But to get to some of the more interesting research, you have to read through papers with titles like, The fluid dynamics of canine olfaction: unique nasal airflow patterns as an explanation of macrosmia. (Does Google offer a translation programs for scientific lingo?)
I look forward to sniffing out what they come up with next.

Survey: Children Raised With Pets Are More Confident, Caring

According to a new survey, children raised with pets feel more confident, caring and responsible than their pet-less peers. Commissioned by Pets at Home, the survey of 1,000 pet-owning children suggests that those who share a home with one or more pet are not just physically healthier – they also enjoy mental health benefits from pet ownership.
Nearly half of survey respondents reported that living with a pet makes them happier. Thirty percent of those surveyed said they felt more calm in the presence of pets, and twenty percent said their pets actually make them feel more intelligent.
Wildlife TV presenter Michaela Strachan says she has seen evidence of those findings in her own children in an interview with the Daily Mail.  “I have a seven-year-old and three older step children. We have a Jack Russell and my stepdaughter has two rescue dogs. Toto, our dog, is part of our family and has brought huge benefits to Ollie, my son. Jade’s two rescue dogs, Marley and Timmy, have had a really positive impact,” she said.
The survey also notes that more than a third of children living with pets say they have become more caring, and that they feel a greater overall sense of responsibility. Twenty percent of survey participants said having pets made them feel more confident when speaking with others.
Parents worried that pets will distract their children from their studies should allay those concerns: the majority (79%) of those surveyed claimed that their pets have had a positive effect on their homework and schoolwork.
Strachan agrees. “Owning a pet can bring so much pleasure to a family. It can increase a child’s sense of responsibility, nurture a more caring attitude and develop self-confidence and, in the case of having a dog, it encourages kids to get outside more. There can be so many benefits.”