How the Smell of a Dog Has Benefitted Humans

Humans and most other animals rely on eyesight for navigation, but a canine is motivated by scent. 

With an ability to smell up to 100,000 times better than humans, dogs can detect odors in parts per trillion, equivalent to a dog locating one dirty sock among two million clean ones.

Humans have harnessed a dog’s impeccable smelling capacity in disease detection, search and rescue, medical detection, emotional detection and support, environmental exploration, and assisting disabilities.

Read on to explore how a dog uses smell to understand the world and how humans have benefited from it.

Why and How Dogs Smell?

Recent research utilizing MRI scans on the brains of dogs has demonstrated just how much their sense of smell works like our sense of sight.

Animals have approximately 300 million receptors in their noses; in contrast, humans only have six million.

The moist leathery surface of a dog's nose plays a crucial role in determining the direction of air currents. 

It helps them track scents and locate the source of odors more efficiently. Sniffing brings air with scents directly into the nostrils, allowing the dog to capture more odor molecules. 

The moist surfaces inside the nasal cavity catch these molecules, and the specialized olfactory receptors in the dog's nose decode the scent information.

Perhaps more impressively, the part of the brain that analyzes scents is 40 times larger in dogs than in humans.

Let's look at how their acute sense of smell developed.

  • Hunting for food: When hunting for food, dogs can pick up on the scent of potential prey, such as small mammals, birds, or even insects, which helps them track potential prey and threats.
  • Communicating: Dogs use scent to communicate with other dogs and animals. They use the vomeronasal region of their brains to detect pheromones from another dog. For example, a male dog is believed to smell a female in heat about three miles away. This is because of the pheromones released in the urine by the female in estrus.
  • Detecting Danger: Dogs can receive historical information about their environment through their nose. Their keen sense of smell allows them to detect unfamiliar scents associated with the environment and wild animals that may pose a danger.

  • Homing Instinct: Dogs have an acute sense of smell that allows them to detect and follow scent markers left behind by themselves or others. 
  • Understand the World: When dogs encounter a new place or object, they sniff to gather information. By smelling the scent molecules left behind by other animals, humans, or things, dogs can gain insights into who or what has been in the area, potential threats, or even the availability of resources like food or water.

How Dogs Help Humans with Their Smelling Capability?

Dogs’ ability to smell at such incredible rates comes from their physiology, habitat, and gradual mutation.

Nonetheless, humans are benefited massively from dogs’ impeccable olfaction.  They can detect scents far better than any artificial machine.

Here is how the smell of dogs has benefited humans.

  • Search and Rescue

Did you know dogs can smell objects and people over 12 miles away? They have an innate ability to track scents over long distances, making them good trackers for the police and military.

They can follow a trail left by a person or animal by sniffing and analyzing the scent molecules dispersed in the air or deposited on the ground.

This makes them valuable companions in search and rescue missions and hunting activities.

  • The unique sense of smell allows them to pick up and follow scent trails, aiding search and rescue operations.
  • By communicating through scent, dogs can help locate lost or trapped individuals, improving the chances of a successful rescue.
  • They can recognize the smell of narcotics, drugs, and weapons, especially during airport searches.
  • A dog’s sense of smell also helps find corpses on land and in water. It can smell blood from far away and effortlessly follow a scent trail, leading authorities toward a victim.

During search missions, many dog hunters follow the smell of a lost person, even in challenging conditions. 

As a result, dogs often bring about a successful end to many rescue missions.

  • Medical Detection

Did you know a study found that trained dogs could detect lung cancer in people with striking accuracy?

Dogs can catch diseases early on by smelling them before any visible signs. They can see changes in human scent associated with certain medical conditions.

They are trained to detect various medical alerts and assist humans in several ways. Here are some examples.

  • Dogs can detect specific scents associated with medical conditions, such as cancer, diabetes, seizures, and certain infections.
  • They can detect allergens or specific medical conditions. For example, dogs can detect allergens or changes in blood sugar levels for individuals with diabetes. 
  • They can sense physiological changes associated with an impending migraine, such as increased body temperature or specific scent cues.
  • They can detect the onset of seizures in individuals with epilepsy. The behavioral and physiological changes occur before a seizure, such as changes in scent, body language, or subtle cues.

By alerting their owners or caregivers to potential risks or medical emergencies through scent communication, dogs can help prevent medical issues and provide timely assistance.

More importantly, their ability to detect subtle changes in odor allows them to alert their owners or healthcare professionals to potential health issues, potentially saving human lives.

  • Emotional Detection and Support

Dogs can also sense human emotions through smell. They can detect changes in hormones and chemicals released when a person is fearful, anxious, or stressed.

Studies have shown that dogs are highly perceptive of human emotions. They can accurately discern positive and negative emotions, such as happiness, sadness, fear, and anger, based on facial expressions, vocal cues, and scent cues.

Here is how dogs use their sense of smell to detect emotions and provide support. 

  • When humans experience certain emotions, their body chemistry changes, leading to alterations in their scent. Dogs, with their sensitive noses, can pick up on these changes in smell.
  • Dogs are adept at reading and combining human body language with scent cues. They can observe facial expressions, posture, and other non-verbal cues accompanying specific emotions. 
  • When a person is sad, stressed, or anxious, their body releases certain chemicals that can alter their scent. Dogs can detect these changes and respond with comforting behaviors, such as leaning against their owner, cuddling, or offering gentle nudges.
  • Through their ability to detect and respond to emotional scents, dogs offer consistent support, reduce feelings of loneliness, and help manage symptoms of anxiety, depression, or PTSD.
  • Dogs can alert their owners or caregivers to changes in their emotional state. They may nudge, paw, or provide other cues to indicate when they sense distress or anxiety. 
  • By recognizing and responding to these signals, individuals can proactively manage their emotions or seek additional support.

The ability of dogs to detect human emotions through scent and respond with empathy and support is a remarkable quality.

Additionally, the positive impact of therapy dogs on human well-being is widely recognized, and their presence can significantly improve the quality of life for those experiencing various challenges. 

The unconditional love, support, and companionship that therapy dogs offer can significantly improve people's emotional and mental health as well as help them deal with their difficulties.

Moreover, it helps build trust and deepens the emotional bond between dogs and humans.

  • Environmental Exploration 

Did you know dogs have excellent senses and can detect objects or human smells 20 km away under perfect conditions?

Due to their susceptible sense of smell, dogs are being used as modern, super-sensitive mobile area scanners, detecting specific chemical signals in real-time in various environments outside the laboratory and tracking the odor of dynamic targets to their source, also in crowded places.

They can detect and identify various scents from objects, other animals, food, plants, and even changes in weather conditions.

Here is how dogs use scent for environmental exploration and support.

  • Dogs can detect various environmental hazards such as gas leaks, mold, or other potentially harmful substances that may be present in the environment. 
  • They can assist in locating missing individuals, whether in natural disasters, wilderness areas, or urban settings.
  • They follow scent trails left behind by humans or other animals over various terrains and conditions, providing valuable assistance in tracking lost individuals, suspects in criminal cases, or even locating wildlife for research purposes. 
  • They can detect specific scents, such as those of endangered species or invasive species, helping researchers and conservationists monitor and protect wildlife populations. 
  • They assist in environmental monitoring projects by detecting and alerting to changes in scent associated with pollution or contaminants. They can recognize specific scents, such as oil spills or chemical leaks.

By alerting humans to these hazards, dogs help ensure safety and prevent potential health risks. 

The remarkable sense of smell possessed by dogs allows them to explore and understand their environment in ways that humans cannot. 

Dogs' scent-based exploration of the environment enables them to provide critical support and enhance our understanding and interaction with the world around us.

  • Assistance for Disabilities

It is estimated that 500,000 service dogs assist people with disabilities in the USA.

Scent communication can be utilized in service dogs trained to assist individuals with disabilities. 

For example, guide dogs for the visually impaired can communicate through scent to help their handlers navigate and avoid obstacles. 

Here are some ways.

  • Dogs can assist visually impaired individuals, such as identifying low-hanging branches, detecting the presence of oncoming vehicles, or locating specific places or entrances based on scent cues.
  • They can assist individuals with mobility impairments by retrieving objects, opening doors, assisting with balance, or providing stability while walking. 
  • They assist individuals with medical conditions. For example, a dog can detect a drop in blood sugar levels for a person with diabetes and alert them or their caregiver to take necessary action.
  • Certain dogs can sense the onset of seizures in individuals with epilepsy before the seizure occurs. 
  • Dogs can help individuals with autism spectrum disorders. They can help with tasks such as tracking or finding a lost child, preventing wandering, or providing a calming presence during distress. 
  • Dogs can help those with psychological disorders, such as post-traumatic stress disorder, anxiety disorders, or depression, providing emotional support, interrupting anxiety or panic attacks, or fetching medication during a crisis. 

Check this infographics out as well. 

Dogs can also retrieve specific objects or signal for assistance in emergencies, enhancing the independence and safety of individuals with disabilities.

They undergo specialized training to respond to these scent-based cues and provide assistance accordingly. 

Through their scent-related abilities, dogs can enhance the independence, safety, and well-being of individuals with disabilities.


A dog's sense of smell is a powerful tool that allows them to navigate and understand the world in ways that are far beyond human capabilities. 

Their exceptional olfactory abilities bridge humans and the natural world, enabling them to assist, protect, and connect with us profoundly and meaningfully.

Get in touch with Urban Pet Hospital & Resort, the best pet hospital in Urbandale, for detailed information.

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