Can horses smell fear?

A recent study suggests horses may be able to smell human fear when presented with their body odour.

Researchers at the University of Wrocław presented twenty-one Thoroughbred and Arab horses with body odour samples collected from humans who were either happy after watching a cartoon, or frightened after watching a horror film.

Before watching the films, the humans had spent a couple of days only washing in unperfumed soap and had not smoked, drunk alcohol, eaten strong-smelling food, or performed any strenuous exercise so that their scent would be as neutral as possible. Whilst watching the cartoon or horror films the human subjects had sterile pads in their armpits to collect their body odour.

The pads were then presented to the horses and their response to the smell of fear, happiness, or a control (without odour) was recorded.

The research team found that horses showed quite different behaviours in response to the odours. They lifted their heads significantly more frequently and for longer in response to the fear odour and the control, compared to the happiness odour.

Similarly, the horses tended to touch a familiar person that was present during the test more frequently and for longer in the fear condition compared to the happiness condition.

The researchers concluded that the presentation of human body odour from humans in different emotional states is enough to induce different behavioural responses in the horse.

You can read the study in full here: https://doi.org/10.1016/j.applanim.2020.105072