Olfaction - the forgotten sense (in applied ethology)

Olfaction is the primary sensory modality for most vertebrate species kept by humans. The olfactory system has received considerable attention in neuroscience studies – and even more so in recent years as a reduced sense of smell has been found to be among the first symptoms of certain neurodegenerative disorders. In farming practice, odours are sometimes used as an aid in the management of production animals. Examples are when a lamb is coated in placental fluids from a foreign ewe to facilitate fostering, or when boar-spray is used to determine whether a sow displays oestrus behaviour to allow artificial insemination. But when it comes to applied ethology, the scientific study of olfaction is sparse. Despite many of our farm species having a highly developed sense of smell (coming from ancestors which depended largely on olfaction for survival), we do not use odours to any large extent in our study of their behaviour and welfare. This is largely due to the difficulties involved in controlling odorants and volatile compounds within an experimental protocol, but also because – among the human senses – olfaction is not one of the major modalities. I will present a brief history of olfactory behaviour research, mainly through illustrative examples of the influence of odours on learning, memory, mate choice, predator avoidance and food preferences. And I will ask the question: Are there lessons to be learned from neurobiology and the plasticity of the olfactory system? Based on our current knowledge of evolutionary biology, olfactory neuroscience, and applied behaviour science, I will put forward the argument that if our aim is to improve animal welfare as well as production, olfaction and odours should be taken into account to a much larger extent than is presently the case. By using the right odours at the right time in the housing and handling environments of farm, zoo, lab, and companion species, we may be able to create dynamic, species-specific odour-scapes. This would help us to be more successful in creating animal environments that are suitable and enriched, also in the eyes – or rather, the nose of the recipient.