Licking and chewing: Food for thought
In the Natural Horsemanship parlance when a horse begins to lick and chew while in the round pen this is seen as the pivotal point where the horse says, “I accept you as my alpha leader; I am ready to join up and follow you anywhere”. However, a dive into the science behind licking and chewing offers a different explanation – one that creates a more just and realistic playing field and gives our horse a better chance for successfully meeting our training goals.
Dr. Sue McDonnell, equine scientist and head of the Equine Behavior Lab at the University of Pennsylvania’s New Bolton Center says that licking and chewing arises as the horse transitions from activation of the sympathetic nervous system (Yikes!!! Incoming floating white plastic bag! Time to get the hell out of Dodge!) to the parasympathetic nervous system (Danger averted; deescalate, Breeeaaathe). Dr. McDonnell notes that licking and chewing most likely originates from a surge in saliva output as the body switches from the dry mouth typical of the sympathetic nervous system (pain, fear, or confusion can all turn on the sympathetic system), to the return of saliva associated with the resulting body relaxation of the parasympathetic system. These behaviors are nearly always indicative of a horse being released from a higher to lower state of alarm or distress. In the round pen the horse is chased, the alarm system is activated, eventually the horse tires, the pressure eases off, the immediate threat is diminished, and the parasympathetic nervous system works to return the horse to a state of equilibrium.
In a 2018 study, equine researchers Margrete Lie and Ruth Newberry studying 200 feral horses in Ecuador, discovered that in threatening encounters, both the aggressor and the submissive horse licked and chewed. Interestingly, and counter to the licking and chewing as submission explanation, aggressors engaged in this behavior slightly more often than the submissive horses.
That the trainer needs to become the horse’s alpha leader because this mirrors how horses relate to one another under natural circumstances oversimplifies the complex social structure of equine herd living. Horses hierarchies are fluid, context specific, and more likely to be bilateral (i.e. where each horse has an individual relationship with each other horse) rather than retaining a concept of an inflexible hierarchy of the entire group across all situations.
The dominance/submission model also suggests that horses’ undesired behaviors stem from a defiance to the trainer’s authority, and thus overlooks the multitude of more plausible and parsimonious explanations – that the horse is in pain, does not understand the question, that there is no correct response, or that the horse is physically or psychologically unable to comply. Ultimately, the simplistic explanations of a complex social structure which is used to justify a dominance training method misrepresents how horses learn, is potentially counterproductive to training, and could well jeopardize horse welfare.
See also the International Society for Equitation Science position statement on dominance: https://equitationscience.com/equitation/position-statement-on-the-use-misuse-of-leadership-and-dominance-concepts-in-horse-training