Horses (Equus caballus) discriminate body odour cues from conspecifics.

This research article documents a study exploring the ability of horses to distinguish different body odours from other unknown horses within their species. The study revealed that horses decreased their interest in a familiar odour when exposed to it repetitively and showed more interest in a new, unfamiliar odour when presented.

Research Purpose and Methodology

The main objective of this research was to understand the ability of horses (Equus caballus) to recognize and discriminate between the body odours of unfamiliar conspecifics, or beings within their own species. This knowledge can potentially inform more effective and species-appropriate harnessing and management techniques for horses.

• The researchers applied a particular scientific procedure referred to as the ‘habituation-discrimination procedure’ in order to investigate this phenomenon.
• The body odours from unfamiliar horses were obtained by rubbing material onto the coat of a horse, after which these samples were presented to a cohort of 16 different horses of the same sex and around the same age.
• The test was comprised of two successive two-minute presentations of a particular individual’s odour, followed by a simultaneous presentation of the same individual’s odour (‘A’) and a new individual’s odour (‘B’) in a final third presentation.

Study Findings

The research findings indicated that horses were able to differentiate between the two different body odours.

• All the horses, regardless of their sex, exhibited a decline in their interest towards the odour of the conspecific during the initial two presentations. This phenomenon is known as ‘habituation’ – a decrease in response to a stimulus after being exposed to it repetitively.
• In the final presentation, horses showed a significantly greater interest towards the body odour of the new horse (‘B’) compared to the one they had been pre-exposed to (‘A’). This suggested successful discrimination of the new odour from the previously experienced one.

The findings led to the conclusion that horses can, in fact, discriminate between two stimuli that are derived from the body odours of unfamiliar horses within a relatively short time.