text: 10 February 2016 Last updated at 14:11 GMT
  A team at the University of Sussex put heart monitors on horses and showed them pictures of faces to see how they reacted to different emotions.
  They found that the angry faces made the horses' heart rates speed up quicker than the happy faces.
  Amy Smith, one of the researchers, explains more.
target: Horses can tell if people are happy or angry, according to a new experiment.