Do different dog breeds or even wolves really have different olfactory capacities?

A Test of Canine Olfactory Capacity: Comparing Various Dog Breeds and Wolves in a Natural Detection Task

Many dog breeds are bred specifically for increased performance in scent-based tasks. Whether dogs bred for this purpose have higher olfactory capacities than other dogs, or even wolves with whom they share a common ancestor, has not yet been studied. Indeed, there is no standard test for assessing canine olfactory ability. A study published in May 2016  aimed to create a simple procedure that requires no pre-training and to use it to measure differences in olfactory capacity across four groups of canines: (1) dog breeds that have been selected for their scenting ability; (2) dog breeds that have been bred for other purposes; (3) dog breeds with exaggerated short-nosed features; and (4) hand-reared grey wolves. The procedure involved baiting a container with raw turkey meat and placing it under one of four identical ceramic pots. Subjects were led along the row of pots and were tasked with determining by olfaction alone which of them contained the bait. There were five levels of increasing difficulty determined by the number of holes on the container’s lid.

The test setup is shown in the below video examples:

  • Video. Examples of indications in the wolf sample. (MP4)
  • Video. Examples of indications in the dog sample. (MP4)


The test results

The test results

Scenting dog breeds perform better then others

The results of this study show that breeds that had been originally specifically selected for scent work do in fact demonstrate a higher olfactory acuity than breeds that had not been selected for such work. Not only were they more successful than the other groups, but they were also the only dog group to perform above chance at the most difficult level. These results suggest that, although modern day dog ownership tends to focus more on suitability for companionship or morphological characteristics, rather than the original function for which the breed was selected, scenting breeds have nevertheless retained the abilities for which they were originally bred.

Short noses have a detrimental effect on olfaction

The findings also support the assumptions that breeding for short noses has had a detrimental effect on olfaction; causing short-nosed breeds to have the worst performances out of the breed groups we measured.

Natural detection tasks are more reliable than tests that require pre-training

While the Natural Detection Task in this study requires no training and relies on the animal’s inherent motivation to find the target (which is in itself the reward), there are studies with different results that required extensive training across multiple days to train the dogs to signal for a biologically irrelevant odor (mineral oil) and then receive a reward. This suggests that performance on such an odor discrimination task is dependent not only on olfactory ability, but also on trainability and motivation.
In conclusion, the major advantage of natural detection tasks as tests for the olfactory capacities is the speed of testing, allowing for the rapid screening of relative olfactory function in groups of dogs. The Natural Detection Task is a simple and practical method for comparing canine olfactory abilities both on the group level and on the individual level without any pre-training.

Cited from Polgár Z, Kinnunen M, Újváry D, Miklósi Á, Gácsi M (2016) A Test of Canine Olfactory Capacity: Comparing Various Dog Breeds and Wolves in a Natural Detection Task. PLoS ONE 11(5): e0154087. doi:10.1371/journal.pone.0154087

Copyright: © 2016 Polgár et al. The study is an open access article distributed under the terms of the Creative Commons Attribution License.

(Foto: The test setupCC BY 4.0)

(Foto: The test setupCC BY 4.0)

(Foto: The test resultsCC BY 4.0)