The discrimination of dog odours by humans

The domestic dog is able to identify both individual conspecifics, i.e. other dogs, and individual interspecifics, e.g. humans, by smell. Whilst humans can recognise individual members of their own species using olfactory information, it is unknown whether they can identify members of any other species in this manner. We examined the ability of humans to identify individual dogs by smell. Twenty-six dog owners were required to smell two blankets, one impregnated with the odour of their own dog, the other impregnated with the odour of an unfamiliar dog. Participants were required to indicate which of the odours smelt the strongest, which smelt the most pleasant, and which of the odours belonged to their own dog. Most of the participants (88.5%) were able to recognise the odour of their own dog. They showed no significant bias, however, in responding which of the odours they thought smelt the strongest or most pleasant. The results indicate that dogs produce odours that are individually distinctive to their owners, and highlight the fact that humans can recognise members of another species using olfactory cues--an ability presumably acquired without conscious effort.