Overview
- INRAE researchers reported in PLOS ONE that horses altered behavior after smelling human sweat linked to fear compared with neutral or positive samples.
- Cotton pads collected from volunteers during a horror film and during relaxing videos were placed in lycra muzzles worn by the animals to deliver the odors.
- Across grooming, umbrella-startle, human-approach, and novel-object tests, exposed horses stared longer, startled more, and were less likely to touch or approach a person.
- Physiological monitoring showed higher peak heart rates under the fear condition while cortisol measures did not differ significantly between groups.
- The team did not analyze the chemical compounds in the sweat, leaving the specific cues and whether responses are learned or innate as open questions with implications for training and welfare.