It’s hard not to be impressed by the dog who speeds around the search area appearing totally engaged with the task in hand as he tries to locate his target scent. In comparison, the dog who moves more slowly is often overlooked in favour of his flashier counterpart. But, where scent detecting is concerned, speed might not be everything and selecting the right breed for the job may be more a matter of taste than a matter of science.
In the UK, the most commonly selected breeds for scent detecting work include (amongst others) Labradors, Spaniels, Border Collies, German Shepherds and Malinois. But which breed is best?
Gadbois and Reeve (2014) favour the Border Collie, basing their preference, amongst other things, on the breed’s apparent persistence and good sniffing ability. They propose that certain breeds have higher baseline levels of dopamine than others which, they state, “raises the intriguing possibility that baseline dopamine levels may have a direct impact on cognition, motivation, learning, and overall olfactory behaviour and performance”. They refer to this possibility as their “dopamine hypothesis” and link this to the notion of “work ethic”. Other breeds they single out as “dopamine dogs” include Belgian Malinois and Jack Russell Terriers. More about dopamine in a future blog.
All that said, Hall, et al (2015) and Rooney and Bradshaw (2004) argue that the choice of working dog may have far more to do with historical precedent than any real evidence of superior scent detecting ability. According to Johnen, et al (2017), good quality empirical studies remain thin on the ground and as Jamieson, et al (2017) warn, “continually selecting the same dog breeds, without inspecting other breeds, may reduce the effectiveness of detection dog programs”.
Interestingly, in McCulloch, et als (2006) study investigating the ability of dogs to detect early- and late-stage lung and breast cancer, it was a mix of pet dogs (rather than ‘working’ dogs) with only basic puppy training who (in a matter of weeks) were able to accurately identify breath samples from lung and breast cancer patients.
Hall, et al (2015) argue for the need for “direct behavioural measurement of assumed behavioural breed differences”. Contrary to all expectations, in their 2015 study comparing the scent detecting abilities of German Shepherds, Greyhounds and Pugs, the Pugs significantly outperformed both other breeds.
Whilst Hall, et als (2015) study may not have persuaded you to purchase your first scent detecting pug … well, not yet anyway … it does raise another important question. Did the Pugs succeed because of their superior olfactory ability or because of the training methods employed in the study?
In an attempt to address this question, Polgar, et al (2016) developed a simple strategy to measure differences in olfactory ability that did not require any pre-training. Raw turkey meat was placed under 1 of 4 ceramic pots. Five levels of difficulty were arranged by way of decreasing numbers of holes in the ceramic pots. Subjects were assigned to one of four groups; dog breeds selected for their scent detecting abilities, dog breeds selected for other purposes, dog breeds with short noses and hand-reared grey wolves. The dogs / wolves were led along the row of pots to identify, by scent alone, which contained the meat. Dog breeds selected for scent detecting work out-performed both the short nosed breeds and those bred for other purposes. At the most difficult level, wolves and the scenting breeds performed better than chance.
Interestingly, according to Maejima, et al (2007), “research with drug detection dogs failed to reveal any significant link between performance and theoretically relevant genotypes” however, Lesniak, et al (2008) argue that breed and heredity may have some influence on scent detecting ability … “there may be a relation between a certain genotype at a particular locus and the ability of more accurate scent detection of particular volatile organic compounds”. This raises the intriguing possibility that not only may some breeds (or individuals within a breed) have better olfactory abilities than others but that some breeds (or individuals within a breed) may have better olfactory abilities when tasked to detect particular target scents.
Similarly, we also show variation in our ability to detect certain odours. Odour sensitivity is heritable. One well referenced example of this “specific anosmia” relates to the ability to detect a sulphurous odour in urine following asparagus consumption (Pelchat, et al (2011)). Some of us can smell it, some of us can’t. Could our dogs also have “specific anosmias”?
Returning then to the original subject of this blog. Tortoise or Hare? Accuracy or speed? According to Helton (2009) “a dog may quickly find substances, but may miss targets because of haste. A dog may also be very slow to find substances, but based on a methodical approach may miss few or no targets”. Self-evidently, a dog whose performance is both accurate and fast seems hugely desirable and, as Helton (2009) suggests, “training and practice can markedly improve skill” … a combination of speed and accuracy, perhaps?
But, can training and practice really alter your dog’s general “approach” (or speed) to scent detecting work? Can you turn your slow and thoughtful Rottie into a speedy working Cocker? Experience would suggest not. Each breed (and every dog within that breed) comes with its own, highly individual, set of characteristics; a mixture of heredity and past life experiences. Far better to work with the dog you have in front of you than attempt to turn him into something he can never be. For me, one of the big enjoyments of working with so many different breeds is their very different styles of working. Each and every one of them brings something new to scent detecting and helps break down any stereotypical views of what different breeds might be capable of. Tortoise or Hare … I’ll take both please!
So, a thought to leave you with. When Helton, et al (2009) asked a trainer which breed was best as an explosives detector dog, his reply was … “depends on where you live, you see here in the United States it is the Labrador Retriever, in the United Kingdom it is the Springer Spaniel, in Belgium it is the Belgian Malinois, in Germany the German Shepherd, and in Norway, they are pushing the Norwegian Drever, a dog most people have never heard of. Personally, I think it is all goofy, pick any dog you are comfortable with”.
And, if you think a Norwegian Drever might be the scent detecting dog for you … just follow this link … https://www.skk.se/en/NKU-home/nordic-dog-breeds/sweden/drever/
© Lesley McAllister – Scent : Detect : Find Ltd 2018
References / Further Reading
- Gadbois S and Reeve C (2014) Canine Olfaction: Scent, Sign, and Situation. IN: Horowitz A (Ed) Domestic Dog Cognition and Behavior. The Scientific Study of Canis Familiaris. London: Springer.
- Hall N J, Glenn K, Smith D W and Wynne D L (2015) Performance of Pugs, German Shepherds and Greyhounds (Canis Lupus Familiaris) on an Odor Discrimination Task. Journal of Comparative Psychology. 129(3). 237-246.
- Helton W S (2009) Overview of Scent Detection Work. Issues and Opportunities. IN: Helton W S (Ed) Canine Ergonomics. The Science of Working Dogs. London: Taylor and Francis Group.
- Helton W S, Feltovich P J and Velkey A J (2009) Skill and Expertise in Working Dogs. A Cognitive Science Perspective. IN: Helton W S (Ed) Canine Ergonomics. The Science of Working Dogs. London: Taylor and Francis Group.
- Jamieson L T J, Baxter G S and Murray P J (2017) Identifying suitable detection dogs. Applied Animal Behaviour Science. 195. 1-7.
- Johnen D, Heuwieser W and Fischer-Tenhagen C (2017) An approach to identify bias in scent detection dog testing. Applied Animal Behaviour Science. 189. 1-12.
- Lesniak A, Walczak M, Jezierski T, Sacharczuk M, Gawkowski M and Jaszczak K (2008) Canine Olfactory Receptor Gene Polymorphism and Its Relation to Odor Detection Performance by Sniffer Dogs. Journal of Heredity. 99 (5). 518-527
- Maejima M, Inoue-Murayama M, Tonosaki K, Matsuura N, Kato S, Saito Y, Weiss A, Murayama Y and Ito S (2007) Traits and genotypes may predict the successful training of drug detection dogs. Applied Animal Behaviour Science. 107. 3-4. 287–298.
- McCulloch M, Jezierski T, Broffman M, Hubbard A, Turner K and Janecki T (2006) Diagnostic Accuracy of canine Scent Detection in Early- and Late-Stage Lung and Breast Cancers. Integrative Cancer Therapies. 5(1). 30-39
- Pelchat M L, Bykowski C, Duke F F and Reed D R (2011) Excretion and Perception of a Characteristic Odor in Urine after Aspragus Ingestion: a Psychophysical and Genetic Study. Chemical Senses. 36. 1. 9-17.
- Polgar Z, Kinnunen M, Ujvary D and Gacsi M (2016) A Test of Canine Olfactory Capacity. Comparing Various Dog Breeds and Wolves in a Natural Detection task. Plos One. May. 1-14.
- Rooney N J and Bradshaw J W S (2004) Breed and sex differences in the behavioural attributes of specialist search dogs – a questionnaire survey of trainers and handlers. Applied Animal Behaviour Science. 86. 123-135.