Olfactory detection and discrimination in domestic dogs (Canis lupus familiaris)

Abstract

The extraordinary olfactory capabilities in detection and rescue dogs are well-known. However, the olfactory performance varies by breed and search environment (Jezierski et al., 2014), as well as by the quantity of training (Horowitz et al., 2013). While detection of an olfactory cue inherently demands a judgment regarding the presence or absence of a cue at a given location, olfactory discrimination requires an assessment of quantity, a task demanding more attention and, hence, decreasing reliability as an informational source (Horowitz et al., 2013). This study aims at gaining more clarity on detection and discrimination of olfactory cues in untrained dogs and in a variety of dog breeds. Using a two-alternative forced choice (2AFC) paradigm, we assessed olfactory detection scores by presenting a varied quantity of food reward under one or the other hidden cup, and discrimination scores by presenting two varied quantities of food reward under both hidden cups. We found relatively reliable detection performances across all breeds and limited discrimination abilities, modulated by breed. We discuss our findings in relation to the cognitive demands imposed by the tasks and the cephalic index of the dog breeds.

Olfaction evaluation in dogs with sudden acquired retinal degeneration syndrome

“…neurons while have around 6-30 million; this difference the number of receptors is thought to play a large role in dogs' keen sense of smell. [72][73][74][75][76] Also, canine olfactory receptor cells contain hundreds of cilia while human cells contain about 25 cilia/cell. 27 Olfaction capability has been shown to differ by dog breed as breed relates to the length of the snout, but in the current study each group was represented by several various breeds and snout lengths in low numbers, thereby eliminating any possible conclusions of breed as a factor of olfactory threshold scores.…”

“…Unique to olfaction and not present in vision, olfactory sensory neurons are capable of regeneration due to resident stem cells within the neuroepithelium and are capable of turnover within approximately 2 months 48,69–71 . Dogs have an estimated 200 million olfactory receptor neurons while humans have around 6–30 million; this difference in the number of receptors is thought to play a large role in dogs' keen sense of smell 72–76 . Also, canine olfactory receptor cells contain hundreds of cilia while human cells contain about 25 cilia/cell 27 .…”