Horses Smell Our Fear

Prof Nat Waran - NavigateWelfare.com

Most equestrians have had the feeling that their horse ‘knows’ when something is wrong. Now a growing body of research confirms that horses can genuinely detect human fear through smell alone, and smelling your fear affects how they feel and behave. Handler/rider emotional state is a critical consideration for horse and rider safety as well as horse welfare.

Smell of Fear

We tend to think of our horses reading our body language, our posture, the tension in our hands or legs. And they do all of that. But research now shows that smell is another significant channel through which horses pick up on our emotional state, and one that operates even before we have made a single visible movement.

When we experience fear or anxiety, our bodies go through a series of physiological changes. Adrenaline and cortisol are released, heart rate rises and the composition of our sweat changes. Those changes produce what scientists call chemo-signals: airborne chemical compounds that carry information about our emotional state.

Horses, with their highly developed sense of smell, and ability to detect these chemical messages, are extremely sensitive to the information we convey.

The Research

A series of studies over the past few years has provided some interesting information. In one experiment, horses were able to reliably tell apart human sweat collected whilst someone was frightened from sweat collected whilst someone was happy, using smell alone. They did not need to see the person or hear them. The scent was enough.

The most detailed study to date, published in 2026, took this further. Horses were fitted with specially designed muzzles containing cotton pads soaked in human sweat from humans who had experiences either a fearful or a joyful context. Horses exposed to body odour from people watching scary films startled more easily, their heart rates were higher, they spent more time watching a novel object placed nearby, and they were noticeably less willing to approach or make contact with the handler in front of them.

Horses respond actively to our emotional state

This is not entirely new territory. Earlier research has already shown that human nervousness can transmit to horses during handling and riding, with measurable increases in horse heart rate even when the handler showed no obvious external sign of anxiety. In other words, the horse was picking something up that the handler thought they had hidden.

But this recent work has gone further, showing that when handlers interact with horses whilst in a stressed or anxious state, the quality of the interaction is negative for both horse and human, and horses respond actively to regulate their own emotional response.

Horses are reading us constantly, through multiple senses, and not surprisingly for a social prey animal with high attuned senses enabling them to swiftly ‘read’ and  respond to the emotionally driven behaviours of the  group, our emotional state is extremely significant to them.

“Horses smell fear. It triggers stress, avoidance and heightened reactivity. Yet handler emotional state is rarely formally measured as part of a welfare assessment.”

 Practical implications?

Think about the situations where a fearful or anxious handler is most likely to be present. Competition day, when nerves are running high. A veterinary visit or a farriery appointment that has not gone well in the past. A horse being loaded after a previous difficult experience. A young or inexperienced person handling a horse for the first time.

In all of these situations, the human’s emotional state is being communicated to the horse through scent, before anything else. If the handler is frightened, the horse perceives this via the chemical signals we unknowingly transmit, and these chemical messages in the horse’s world, convey information about the environment that the horse reads and uses  to keep itself safe. Its natural response when feeling under threat is to become more alert, more vigilant, more reactive, and more ready to flee. The freeze, flight or fight response is triggered and that’s precisely the situation in which accidents are most likely to happen.

In equestrian sport, therapeutic riding programmes and everyday handling, fear-related odours from handlers may inadvertently increase horse insecurity leading to increase reactivity and raise the risk of unwanted behaviour and risky incidents.

Human emotionality is an active variable in the horse’s environment

When we assess a horse’s welfare, we tend to think about functional aspects such as; feed, water, shelter, turnout, social contact and veterinary care. Rarely do we stop to ask about how the handler or rider is feeling when they are in the horse’s environment.

This research suggests that this is a significant gap. Handler emotional state is a variable that directly affects how a horse feels and behaves and therefore is a critical consideration for their welfare state.

A consistently anxious or fearful handler/rider is, in effect, a constant source of stress for the horse.

 This matters for our developing robust welfare assessment frameworks, and also practically for daily management, for riding/driving performance and for handler safety, and crucially is also matters for how we support and educate anyone who works with horses.

Emotional self-awareness and self-regulation is essential for supporting positive horse welfare.

Making sense of horse senses and managing horse behaviour is critical for horse and human safety and welfare. Recent research now shows that equally as important is the emotionality of the human in the system, and the impact this has on the horse’s emotional and behavioural responses.

Key Reference Jardat, P., Destrez, A., Damon, F., Tanguy-Guillo, N., Lainé, A.L., Parias, C., Reigner, F. et al. (2026). Human emotional odours influence horses’ behaviour and physiology. PLOS ONE. 

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