Our Mantrailing Dogs' Amazing Sense of Smell

Samson my trailing dog's nose, is twitching and actively working scent.

Early Mantrailing

Our dogs are incredibly well adapted to smelling. This, combined with their intelligence and pack mentality, which lends itself to teamwork, and their biddable work ethic, makes our dogs perfectly suited to mantrailing.

Dogs have been used to 'track down' people for centuries, with Bloodhounds used in the late 14th century in Scotland to track outlaws.

Today, research has found that police dogs, specifically trained to search for individuals, have a success rate of 82% and can identify when there is no trail to follow in 97% of cases.

When trailing we are tapping into this, whether we are mantrailing or trailing a pet. What surprises most people is how quickly their own family dog makes the connection between a scent to trail and finding the runner.

Why is this?

Well, it's simply because our dog's have an amazingly adapted olfactory (smelling) system! Let's look a bit more at that.

Dog’s Olfactory (Smelling) Anatomy

Dogs' anatomy has developed to such an extent that under perfect conditions, they have been reported to smell objects or people as far as 20km away (Source: University of Adelaide).

So, what adaptations make them so special?

Firstly, as well as breathing through their nose, around 12% of that air is directed to the olfactory epithelium that detects odours. Their adaptations start here. They take in air through their nostrils and breathe it out through the sides so as not to interfere with the smell-processing going on. They also favour one side for some smells, too! This is where they take in the runner's unique smell.

They also have an extra, smelling organ called the Jacobson’s organ (or vomeronasal organ). This is a special organ found in the roofs of dogs’ mouths that helps them smell. Specifically, it detects pheromones that cause changes in dogs’ bodies and behaviour. This organ is why you will sometimes see dogs open their mouths, or chatter their teeth, or ‘click’ when they breathe aromas in. Listen to your dog when they are doing detection work or mantrailing to see if you can hear them making this noise — it's quite a thing to hear, but you'll need to listen carefully, and not all dogs make a noise when doing so. For those interested, it is called the Jacobson's organ, as Danish anatomist Ludvig Levin Jacobson (1783–1843) described it in detail in various mammals in 1813.

Smells are passed through the olfactory epithelium, which in humans is a small patch of about 5 cm². Dogs have a much larger area, ranging from 18 to 150 cm², containing up to 300 million olfactory receptors compared to the 6 million in humans.

The Jacobson's Organ is directly connected via nerves to the Olfactory Bulb, which is roughly 10% of a dog's brain size and considerably larger compared to a human's, which is only about 1%. Smell is very literally a bigger part of a dog's life!

All these adaptations mean that 'fireworks' spark and the 'cogs turn' when our dogs are processing scent. It's one of the reasons that mantrailing is so tiring for them.

Our dogs' olfactory (smelling) system is incredibly well-adapted.

Dogs' Evolution to Smell

Dogs are macrosmatics, which means their primary way of experiencing the world is via their nose. Unlike humans, who are microsmatics who explore first with our eyes.

Dogs have adapted over the years through processes of artificial and natural selection to have a superior sense of smell for many reasons, including:

• Hunting

• To find a mate (A male dog can tell if a female dog is in heat from over 3 miles away)

• For communication — recognising individuals

• Scenting hazards

• Noticing territorial markings

• To ensure they don’t get lost (think of populations that do not live in houses e.g. street dogs abroad).

  
  

Sniffing and the seeking system are with dogs from birth (so they can trail from as soon as they can safely go outside). Tapping into that sequence and teaching a dog to trail is where the fun begins! The nuances of dogs’ noses and scentwork are fascinating, and the more you observe, the more you will learn!

Summary

Dogs possess an extraordinary sense of smell, which, combined with their intelligence and social behaviour, makes them ideal for activities like mantrailing. Historically, dogs have been used for tracking since the late 14th century, with modern research showing that police dogs trained for this purpose have an impressive success rate in locating individuals.

Dogs' olfactory anatomy is highly specialised, enabling them to detect scents from great distances — up to 20 km under optimal conditions. Their nasal structure allows for efficient scent processing, and they possess an additional organ, the Jacobson's organ, which aids in detecting pheromones. With a significantly larger olfactory epithelium and more receptors than humans, dogs experience the world primarily through their sense of smell.

Throughout evolution, dogs have developed their acute sense of smell for various purposes, including hunting, mate detection, communication, and navigating their environment. This innate ability allows them to engage in scent work from a young age, making activities like trailing both enjoyable and mentally stimulating for them.

So, as soon as your puppy is safe to explore, get them trailing to tap into this incredible adaptation.