It’s well-known that dogs have an excellent sense of smell. Humans have been using dogs to hunt and track animals for almost as long as we’ve had them domesticated.
The tracking ability of dogs, to our best estimates, have been used for human purposes for around 12,000 years. The ability of dogs to smell also depends on breed, heritable qualities, and training.
That said, what is the comparison between dog sense of smell vs human smelling abilities? You might be surprised to find out that we’re comparable in some respects.
Let’s take a closer look.
Dog Sense of Smell vs Human Smell
Humans are actually a lot better at smelling than we tend to give ourselves credit for.
When we smell, we take in molecules that activate our olfactory neurons. These molecules come off of different things in our environment and linger for different periods of time.
Factors like smells already present in the area or wind can drastically reduce the number of particular molecules we take in. We have about 400 olfactory sensory neurons that work as receptors to translate olfactory information to the brain.
So, when we smell an orange, these neurons identify it and let our brains know that an orange is in the area. This function helped us evolutionarily to sense predators, find food, and avoid things that will cause us harm.
Over time, those stimuli that were positive for us lead to more enjoyable responses to the smell, while things that were dangerous seemed more repugnant. Of course, it’s not always the case that a dangerous mushroom, for example, will smell bad to everyone.
We’re also tuned to smell things that direct our social interaction. The smell of tears can reduce a person’s testosterone levels, for example. Precisely why this happens is up for debate, but the fact is that tiny signals are picked up by our brains and we respond accordingly.
Dog Sense of Smell
Now, you might be wondering “Why do we need dogs if we can smell something as fine as a tear?”
You don’t see people getting hired to use their nose to track down a wounded animal or a poacher escaping through miles of African desert. Additionally, there aren’t “drug-sniffing humans” waiting for you at an airport terminal.
Doctor Sniffs Bed Bug Dogs service uses canines to identify bed bugs, while there aren’t any humans we can find that could identify a bed bug with their nose.
The dog’s sense of smell has adapted to its needs in the wild and subsequently been fine-tuned through breeding. Dogs are geared for hunting prey and avoiding predators. Humans have the same basic needs, but our capabilities for thought, coordination, and our original environments elevated other senses.
As a result of those factors, dogs can pick up on extremely fine or limited molecules in the air or on the ground. Some estimates say that their sense of smell is thousands of times better than ours when it comes to scouring an environment for a particular smell.
That analogy is a little inaccurate, though, because humans can smell things in a different light than dogs. For example, we can use our sense of smell to craft a really great meal or fine-tune perfume. So, in some respects, we are better at smelling than dogs, while dogs are far-superior at identifying and tracing certain smells.
Interpretation of Smells
As we mentioned earlier, we have somewhere around 400 olfactory receptors working to identify smells. Mice have around 1,000 of them and dogs are much better equipped than mice.
The relationship between neuron count and ability to smell isn’t a direct one, though. Sure, more neurons present help you to pick up on fewer parts per million in the air.
In other words, if there were 6 cocaine particles floating in a sea of 1,000 other smell particles, you’d be better able to smell them if you had more neurons picking up scents.
The piece that sets humans apart from other animals, though, is something called a glomerulus. Glomerulus help to identify and discriminate between smells in a way that’s logical to the brain.
You can think of a creature with thousands of olfactory receptors as someone with a lot of muscle mass, whereas a creature with more glomerulus can use finer, more specific movements.
Humans are equipped with far more glomerulus than dogs or mice are, which gives us the ability to appreciate and understand smells in a more refined way. Dogs are equipped with glomerulus as well.
They serve as a sort of “odor map” that help us to identify different categories of odor and even specific sources of the odors themselves. Of course, our maps become more refined as we experience life and connect smells to their sources.
All smelling animals need these maps because they serve as the guideline for using smell in response to the environment to stay alive.
What Are Dogs Capable Of?
Super smellers that design colognes, perfumes, and product lines are certainly impressive, but some dogs have abilities that are hard to fathom.
Let’s look at the bloodhound, for example. We’ve relied on these furry friends to find and track down criminals for hundreds of years. One interesting use of bloodhounds is in Africa, where a t-shirt left behind by a poacher can serve as the only clue needed.
A bloodhound is equipped with around 40 times as many olfactory cells as humans, and the area of their brain needed to use all of them is much larger than humans.
Something left behind by a human for a few days can be found, analyzed, and used as a tracking device for a bloodhound to find a person who is hundreds, or even thousands of miles away.
Interested in Learning More About Canines?
The dog sense of smell vs human sense of smell is quite impressive. Both of us are equipped in ways that are fine and specific, but dogs really take the award in the debate.
There’s a lot more to learn about man’s best friend, though, and we’re here to put you in touch with it. Explore our site for more information about animals and their relationship to humans.