Can horses smell fear? The hidden signatures in human sweat

Have you ever wondered why horses act differently, depending on who is riding them? Does it purely come down down to skills and experience, or could something else be at play? Can horses smell fear?

We all know that smell is an important part of communication in animals, but what information could be hidden in the smell of sweat? A recent study published in Nature found that horses can discriminate between positive and negative emotions in humans, simply by the sniff of a nostril… 

What did the researchers do?

To explore the idea that horses can discern human emotions from smell, the researchers exposed horses to the sweaty t-shirts from people who watched a scene from either a scary horror movie, or a a comedy. The human participants ranked their emotions, and differed significantly in how scared or joyful they felt while watching the movie clips.

The horses in the study, were initially repeatedly exposed to one of the smells (this was called the habituation phase). They were then exposed to the familiar smell and the novel smell at the same time (this was called the discrimination phase).

What did the researchers find?

When the horses were exposed to both the familiar and novel smells (so, if they had habituated to the ‘joy’ scented shirt, the novel odour would be the ‘fear’ scented shirt) they sniffed the novel smell more frequently. They also differed in how they sniffed – the left nostril was used preferentially for the familiar smell and the right nostril was used preferentially for the novel smell. Another interesting observation was that when the horses were habituating to the smell, they sniffed the ‘fear’ scented shirt much more often than the ‘joy’ scented shirt.

What does it mean for us?

This research study indicates that horses can detect subtle differences in our emotional state from the way we smell. So, it would appear that horses can indeed smell fear. This may not come as a surprise to many of you, I know that my horses can feel very different under saddle, depending on how confident or anxious I am feeling that particular day.

It also highlights the importance of owning our emotions, and finding ways to work through our own fear and anxiety. Our connection with our horse goes both ways – I feel that we need to give and receive confidence and connection when working with our horses. You might be able to ‘fake it until you make it’ in some areas of life, but your horse will always know how you really feel.

Research article reference – Jardot et al., (2003) Horses discriminate human body odours between fear and joy contexts in habituation – discrimination protocol. Scientific Reports volume 13, Article number: 3285

can horses smell fear