Comparing Dog and Human Olfaction

Photo of a map showing the distance from Calgary to Greenland and Mexico City

A dog’s sense of smell (aka olfaction) is 10,000 – 100,000 times stronger than a human’s. What does that mind-numbing number mean?

Picture it on a map. Let’s be conservative: say the canine sense of smell is 10,000 better. According to James Walker, former researcher at the Sensory Research Institute at Florida State University, if you make an analogy to vision, items humans could see clearly at a third of a mile (1/2 km), a dog could see just as well more than 3000 miles away (> 4800 km). That’s about the distance from:

  • Calgary to the North Pole (4,345 km), Greenland (3814 km), Mexico City (3752 km) or the Russian Federation
  • Canada is approx. 5187 km wide and it takes seven days to drive from the west coast in Vancouver, BC to the east cost in Halifax, Nova Scotia.

Depending on the scent and environment, dogs detect one part per billion – trillion (sources disagree on the exact amount). Alexandra Horowitz, a dog-cognition researcher, says that humans can detect a teaspoon of sugar in 1 cup of coffee, while dogs can detect 1 teaspoon of sugar in 2 Olympic sized pools (equivalent to a million gallons of water). According to Nova scienceNOW, That’s like finding a whiff of one rotten apple in two million barrels.




About carlalsimon (84 Articles)
Dr. Carla Simon is a Scent Detection Instructor, Certifying Official (UKC Nosework), and President of Sniff Alberta. She’s been breeding and training scent dogs for Hunter’s Heart since 1999. Carla's evidence-based, motivational training has helped hundreds of scent dogs to reach their potential, with target odors ranging from human scent to bed bugs. Follow her Nosework & K9 Scent Detection Blog at:

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