Groundbreaking new research has confirmed a long-held suspicion among equestrians: horses can literally smell fear in humans. A scientific study has demonstrated that these sensitive animals detect chemical signals in human sweat, causing them to become more jumpy and anxious themselves.
The Science of Smelling Fear
The study, conducted by researchers in France, involved collecting body odour from human volunteers as they watched emotionally charged video clips. Volunteers wore cotton pads in their armpits while viewing scenes from horror films like 'Sinister' and joyful content such as 'Singing in the Rain'. These scent samples were then presented to a group of horses.
Scientists stapled the cotton swabs directly to the horses' muzzles over their nostrils. They then carried out a series of behavioural and physiological tests. These included monitoring how often the animals approached and touched their handler, and observing their reaction to a suddenly opened umbrella.
Clear Physiological and Behavioural Changes
The results, published in the journal Plos One, were striking. When exposed to odours from frightened people, the horses exhibited significant changes. They startled more easily, showed increased peak heart rates, and interacted less with their handlers compared to when they smelled odours from people experiencing joy.
Dr Plotine Jardat, the study's first author and a researcher at the French Horse and Riding Institute near Tours, emphasised the practical implications. She told the Guardian: "Arriving relaxed and in a positive mood can foster a better interaction with the horse, whereas if you are afraid yourself, the horse can feel afraid in response and react more strongly to a potentially scary situation."
Emotions Are Contagious Across Species
The research suggests that fear can be contagious between humans and horses, a phenomenon that may have evolved as a cross-species early warning system for danger. Dr Léa Lansade of the University of Tours stated the study "shows how closely connected animals and humans are". She added that we can unconsciously transmit our emotions to animals, with significant effects on their own emotional state.
This finding adds to a growing body of evidence that emotional communication transcends species barriers. Professor Biagio D’Aniello from the University of Naples Federico II, who has conducted similar research, noted the discovery "raises intriguing questions about how human stress or calmness might shape everyday human-horse interactions, from training to clinical handling."
The research team warns that anyone who works with horses—including riders, trainers, and handlers—should be acutely aware of the emotional impact they can have. The study, dated Friday 16 January 2026, provides a scientific basis for the importance of managing one's own emotions when in the presence of these perceptive animals.
