You don't have to be horse-obsessed to appreciate silly horse behavior. From the Flehmen response to enthusiastic rolling to lip-smacking, quirky behaviors are delightful clues to the unique personality behind each of these gentle giants.
Root, the horse in the video below, is a hilarious example of a lip smacker. He is standing in a stall and secured with cross ties, flapping his lips together incessantly and producing a rubbery smacking sound and making the nearby humans laugh.
However, lip-flapping is occasionally a sign of a problem, warns a post on Equus magazine's website. "If the behavior is new and accompanied by ... signs of agitation, it may signal discomfort [or] colic," the post says. A veterinarian should be called in if the horse's temperature is high or if oral discomfort is suspected.
Flapping the lips during riding or training is most likely caused by anxiety or stress. Have an experienced trainer observe the horse during the activity that causes the flapping; the trainer may be able to see exactly what is bothering the animal.
Neither illness nor stress is Root's problem, however. In the comments on the YouTube video, the original poster, fathorses, explains that Root had just been fed and watered and was actually getting a relaxing bath while the video was taken.
"He's an ex-racehorse, and they sometimes have funny behaviors," fathorses wrote. "It's probably like a person tapping a foot, twirling her hair or some other absent-minded gesture."
Equus agrees. "If your horse flaps his lips while standing quietly in his stall and seems otherwise relaxed, you can probably just chalk the habit up to quirkiness and leave it at that."