Horses or Apes: Which Has More Facial Expressions?

A horse is a horse, of course, of course--but was the horse on TV actually competitive with, say, Jim Carrey, for rubber-faced expressionism?

Well, not exactly--but they have some facial expressions that are surprisingly like those of humans and chimps, say University of Sussex researchers in a report published recently in PLOS One.

These mammal communication researchers have shown that horses alter their facial expressions in many social situations. This suggests evolutionary parallels in different species regarding how the face is used to communicate, according to a statement.

With their Equine Facial Action Coding System (EquiFACS), devised by the Sussex scientists in collaboration with the University of Portsmouth and Duquesne University, they have identified 17 "action units" (these are separate facial movements) in horses, as compared with 27 in humans, 13 in chimps and 16 in dogs, the statement said.

Currently their research is examining how the expressions relate to emotional states, noted the release.

"Through the development of EquiFACS, however, it's apparent that horses, with their complex and fluid social systems, also have an extensive range of facial movements and share many of these with humans and other animals. This contributes to a growing body of evidence suggesting that social factors have had a significant influence on the evolution of facial expression," said co-lead author Professor Karen McComb, in the release.

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