Flared or Widened Nostrils
Look at the signal, then look at the whole horse and the situation around it.
NOTICE
The nostril openings become larger or more open than usual.
The change may be brief or may continue for a while.
WHAT IT MAY TELL YOU
Nostrils can widen for several reasons. The horse may be exercising, breathing more deeply, highly alert, aroused, investigating something, or experiencing discomfort.
DON'T ASSUME
Flared nostrils do not automatically mean fear, excitement, pain, or breathing trouble.
LOOK AGAIN
Ask what the horse was doing just before the nostrils widened. Is breathing faster or harder? Is the body tense? Are the eyes wide? Is the horse exercising, recovering from exercise, or standing quietly?
Research / Learn More
What research shows
Nostril dilation is a visible facial action in horses and can occur in different contexts. It has also appeared more often in pain conditions in some EquiFACS studies.
What it does not tell us
Widened nostrils alone do not identify the cause. Exercise, arousal, pain, and increased respiratory demand can all change nostril opening.
Sources
- EquiFACS — defines nostril dilation as a visible facial movement without assigning a single meaning to it.
- EquiFACS for pain-related facial responses — found nostril dilation among facial actions that were more prevalent in painful horses.