From pinned ears to a cocked hoof, the messages horses convey through body language are well known. Now work is underway in England to find out if they use their faces to communicate as well.

Researchers at the University of Sussex have developed the Equine Facial Action Coding System (EquiFACS) to classify the facial expressions of horses. Formulated based on observations of 86 horses, of various ages and breeds, made using high-tech video, the EquiFACS is an adaptation of a system originally developed for humans and then modified for use in other animals including chimpanzees, dogs and cats.

Through in-depth analysis of each horse’s facial musculature and characteristics during naturally occurring behaviors, the researchers documented 17 distinct and universal facial movements, such as a “mouth stretch” and “nostril lift,” that may be used in communication. By comparison, FACS have cataloged 27 such movements in human faces, 16 in dogs and 13 in chimpanzees. The researchers hope the EquiFACS will provide an objective method for describing the facial expression in horses that will help people determine when they are in pain or are feeling well. 

Reference: “EquiFACS: The Equine Facial Action Coding System,” PLOS ONE, August 2015

This article first appeared in EQUUS issue #457, October 2015.