How Well Can Dogs Smell?
The olfactory capabilities (sense of smell) of canines are extraordinarily powerful. Just a single sniff is enough for a dog to be able to accurately distinguish very similar smells. (1) Essentially, dogs experience the world through their noses as a primary sense, so the importance of smell cannot be overstated.
The Purpose of Sniffing
Males tend to sniff the back end of other dogs, while females tend to sniff up front. (2) The purpose is the gathering of information, both past and present. (3) When out and about, dogs are sniffing for urine scent marks of other dogs who have been to the area. These scents allow dogs to evaluate information such as reproductive status or make assessments of their competitors. It is thought that overmarking other dogs’ scent relates to social status, and it occurs more frequently in males than females. (4)
Scent Detection Work
Humans utilise the exceptional sense of smell of dogs in a number of ways. Canine scent detection is used to detect dangerous or illegal substances such as drugs and landmines with considerably more accurate results than human or machine detection.
In some countries, police dogs are used to identify criminals using the scents found at crime scenes, although this is a controversial approach. Dogs are able to follow a human scent in a busy city up to 2 days after the human has been in the location with nearly 80% accuracy. (5)
Our canine companions are also used after natural disasters and other devastating events to find injured and deceased people. Numerous studies have been conducted into the olfactory capabilities of different breeds, but with differing results on which breed has the most sensitive sense of smell. (6)
Smelling Emotions & Diseases
One study found that dogs are able to distinguish the emotions of fear and happiness by human chemosignals (sweat). (7) Additionally, dogs are often used for monitoring and detection of diseases such as e
pilepsy, diabetes, and even COVID-19. Seizure Alert Dogs (SADs) are specifically trained to warn humans of seizures before they take place. (8) This is related to smell, as well as dogs noticing subtle behavioural changes, and potentially heart rate. Both trained and untrained dogs are able to detect hypoglycemia in diabetic people, which helps to improve their quality of life. (9)
Conclusion
‘When it comes to smells, we should let dogs be dogs and not hold them to human standards of propriety. This means we should let them sniff one another to their nose’s content and we must let their walks be their walks, not ours, as frustrating and challenging as this might be. Their sense organs, like their muscles, heart and lungs, need to be exercised’ (10) – Marc Bekoff
- Kepecs et al., 2005. DOI: 10.1093/chemse/bjj016
- Dunbar, 1977. DOI: https://doi.org/10.1016/S0091-6773(77)91079-3
- Horowitz, 2016. BOOK ‘Being a dog: following the dog into a world of smell’
- Ferkin and Pierce, 2007. DOI:10.1007/s10164-006-0012-1
- Harvey and Harvey, 2003. DOI: 10.1520/jfs2002118
- Tacher et al., 2005. DOI: https://doi.org/10.1093/jhered/esi113
- D’Aniello et al., 2021. DOI: https://doi.org/10.1007/s10071-021-01473-9
- Brown and Goldstein, 2011. DOI: 10.1016/j.eplepsyres.2011.10.019
- Weber et al., 2015. DOI: 10.1111/dme.12975
- Bekoff, 2018. BOOK ‘Canine Confidential’
