10/09/2025
Can Horses Really Smell Fear?
A recent study demonstrated that horses are capable of detecting and responding to human emotional states, such as joy and fear, through olfactory cues.
Specifically, the research showed that horses exposed to human scents collected during episodes of fear or joy exhibited clear behavioural and physiological responses, indicating that emotional signals can be transmitted from humans to horses via scent.
In the study, scientists collected human sweat samples during controlled episodes designed to elicit fear (by having volunteers watch a horror film) or joy (by watching comedic or uplifting videos), ensuring strict controls over hygiene and diet to prevent confounding odour cues.
These human odour samples were then applied via cotton pads to the nostrils of 43 Welsh mares, which were grouped to receive odours from either the fear context, the joy context, or unused/clean control pads.
The horses underwent a series of behavioural tests including grooming with a familiar human, a human approach test, a suddenness (startle) test, and a novel object test to assess their reactions to the different scents.
Physiological indicators, such as heart rate and cortisol levels, were also measured.
Horses in the fear-odour group showed higher maximum heart rates, signifying increased arousal and stress.
Equally important, these horses were less likely to initiate contact with humans, indicating a clear reduction in their willingness to engage socially. These results support the idea of emotional contagion—the transfer of an emotional state from humans to horses via chemosignals.
This research demonstrates how human emotions transmitted unconsciously through smell, may shape horses’ stress levels, reactions, and cooperative behaviours, underscoring the importance of calm, positive human–horse interactions.
📑 Human emotional odours influence horses’ behaviour and physiology by Plotine Jardat and colleagues.
