A mammal communication research conducted by the University of Sussex suggests that, like humans, horses use muscles underlying various facial features including their nostrils, lips and eyes to alter their facial expressions in a variety of social situations. The research is published in PLOS ONE.
Author Jennifer Wathan said, "Horses are predominantly visual animals, with eyesight that's better than domestic cats and dogs, yet their use of facial expressions has been largely overlooked and what surprised me was the rich repertoire of complex facial movements in horses and how many of them are similar to humans. Despite the differences in face structure between horses and humans we have identified some similar expressions in relation to movements of the lips and eyes."
Talking about the development of EquiFACS, a facial expression reading machine co-author Karen McComb said, "A systematic way of recording facial expressions can have a wide range of uses. With EquiFACS we can now document the facial movements associated with different social and emotional contexts and thus gain insights into how horses are actually experiencing their social world."