A stereotypy is an apparently functionless, stylized, repetitive behavior, such as cribbing, weaving, and some types of fence or stall pacing.
Photo: The Horse Staff
Q. What is the difference between a vice and a stereotypy in horses?
A. My answer here might be all about semantics. However, choosing the correct word affects not only our precision in defining specific behaviors but also can affect our tone in how we address a behavior.
In the past, we freely used the terms “vice” or “stable vice” for all manner of things horses did that ranged from dangerous to just really darn irritating, including bucking, cribbing, and dunking hay in water buckets. And all these behaviors have evoked negative feelings, not only about the behavior, but about the horse himself. Some of these behaviors are products of the domestic environment, and some are learned.
A stereotypy is an apparently functionless, stylized, repetitive behavior, such as cribbing, weaving, and some types of fence or stall pacing. There is much research and even more theorizing on the institution and maintenance of stereotypies. There are probably components of poor management, past or present, resulting in a horse with inadequate outlets for normal behaviors. There is what's called emancipation, where the past triggers for the behavior are gone, but the behavior continues anyway. They might be caused by a past or present medical problem, for example gastric ulcers in cribbers.
Stereotypies are resistant to being curbed. For example, cribbers often crib worse as a kind of catch up if they’ve been prevented from cribbing for a while. They generally can’t be successfully punished or retrained away. Evidence suggests that performing a stereotypy is self-rewarding by initiating the release of endorphins. Some believe stereotypies are coping mechanisms and it’s unhealthier for the horse to try to stop them.
Similarly, we consider behaviors that have been called stable vices—such as door banging, pawing, or soiling water buckets by hay dipping—as an understandable response to domestic conditions that are quite suboptimal compared to the natural social and environmental conditions under which horse behavior evolved.
These things that instigate and maintain stereotypies are not the same as those associated with habitual unruly behaviors like bucking, striking, or rearing. Yes, sometimes pain is a component of unruly behaviors. But in a large number of cases, the horse has learned that certain behaviors cause a release of pressure (negative reinforcement). Behaviorists interpret this as simple inadvertent training error, sometimes understandably unavoidable, leading to the horse misunderstanding the task we want.
Actually, I don't care for the word "vice" much at all, for any of these behaviors, even though it's so ingrained in our vocabulary. "Vice" has too much anthropomorphism surrounding it. And particularly in the case of behaviors we'd group as stereotypies or stable vices; it wrongly implies a willful, disobedient demeanor, which certainly does not fit with the attributes I listed above.
And if we stopped calling the other unruly behaviors vices, we might be able to look at them a bit more dispassionately, too. As we've discussed before, a horse that excels at learning a misbehavior can likely also excel at learning a good alternative behavior, given a handler with the right set of tools. When we approach it that way, we have a project, not a vice.
About the Author
Prior to attending veterinary school, Dr. Nancy Diehl completed a master’s degree in animal science while studying stallion sexual behavior. Later, she completed a residency in large animal internal medicine at the University of Pennsylvania’s New Bolton Center and worked in equine practices in Missouri and Pennsylvania. Diehl also spent six years on faculty at Penn State, where she taught equine science and behavior courses and advised graduate students completing equine behavior research. Additionally, Diehl has co-authored scientific papers on stallion behavior, early intensive handling of foals, and feral horse contraception. Currently she is a practicing veterinarian in central Pennsylvania.