Facial expressions
Understanding his mood • A change in behaviour
QHorses have such expressive faces. Do their expressions really denote the mood they look as though they denote? For example, a wrinkled nose looks like pure disgust, but is this possible? Gemma Stonehouse, Co. Durham
Jenni says... Equine facial expressions is a new field of investigation, in which we are starting to see some published research. EQUIFACS stands for Equine Facial Action Coding System and the first paper to come out on this mapped, in fine detail, all the horse’s facial muscles and what movements they could produce — many of the same as in primates, cats and dogs. This perhaps points to a common ancestral root, although a lot more research is needed to determine or discount that.
Bittersweet
Disgust is something that has barely been investigated in horses. In research published before the EQUIFACS work, horses were demonstrated to gape, opening their mouth wide and sticking the tongue out, in response to the bitter taste of quinine. Much as might be seen after the administration of a paste wormer!
The study didn’t look for, or spot, nostril wrinkling, but this kind of protocol might be a good place to start: to present an unpleasant scent or taste and record facial expression. The same study looked at horses’ responses to the sweet taste of sugar, and saw that they repeatedly protruded their tongues.
The grimace scale and pain
The equine grimace scale was developed just before the EQUIFACS paper came out
and identifies a “drawn” nostril as one of the defining features of the facial expression of a horse in pain. The nostril is drawn upwards and outwards so can appear wrinkled.
Other pain indicators were half-closed eyes, ears drooped and turned backwards, clenched cheek muscles, and lips pressed together with a flattened chin.
Stress, fear and anxiety
In recent research, in which EQUIFACS was applied to the study of pain-free horses subjected to the stresses of transport and isolation, the horses were found to have flared nostrils alongside increased eye white, raised eyebrows (which makes the eyes look more triangular), increased tongue showing and more ear movement.
Given the situations the horses were in, along with significantly increased heart rate, it is reasonable to presume this facial expression accompanies fear and anxiety.
Showing pleasure
A horse’s expression of pleasure was identified by comparing horses subjected to a standard grooming procedure with ones groomed in a preferred place only. Those in the standard group showed an expression similar to that of anxiety, whereas those who were groomed where they liked to be groomed held their heads at moderate height, half closed their eyes, turned their ears back and extended their lips forward, twitching them or holding them immobile in a position as if they were grooming back. It’s likely these horses were experiencing pleasure.
With growing amounts of scientifically verified information, one day we will have a good, evidence-based guide to
reading how our horses feel.