b'R esearchers estimate that 2-10% of all horses crib. This stereotypy (de-fined as a relatively unchanging, repetitive pattern of behavior with no apparent goal or function) involves grasping an object with the in-cisors, flexing the muscles on the underside of the neck, and drawing air into the upper esophagus, usually while emitting a characteristic grunt, says Sabrina Briefer Freymond, PhD, a researcher at the Agroscope Swiss National Stud Farm, in Avenches.As a behavioral biologist, Briefer Freymond investigates equine stress physiology and the person-ality and learning capacity of cribbers, striving to better understand this behavior and its effect on horse welfare.Cribbing While some undesirable aspects of cribbing (also called crib-biting) are obvioussuch as damage to the surface the horse gripsother effects might be less clear. For example, horses that crib might be at an increased risk of suffering certain types of colic. In this article well explore the act of cribbing and what we currently know about its link with colic. Why Do Horses Crib? A quick search of the published literature about cribbing reveals multiple theories as to its cause. Some researchers call it a coping mechanism. Colic This hypothesis suggests that stereotypic behaviors develop as a way for horses to cope with stress, such as suboptimal living conditions, says Briefer Freymond. Examples of such conditions include physical confinement and social isolation or problems with diet and feed management. In these situations crib-biting might provide a means of self-soothing, and this behavior allows a horse to decrease their stress level. According to this coping theory, cribbers should have lower cortisol (the stress hormone) levels after cribbing than noncribbers residing in the same environment. Indeed, research shows an increase in cortisol immediately prior to cribbing, followed by an abrupt decrease as soon as horses start cribbing again. However, the coping theory remains hotly debated. Data generated by a group led by Carole Fureix, PhD, an animal welfare lecturer at the University of Plymouth, in the U.K., and a leading researcher in this field, found no difference in either fecal or oral cortisol levels between horses with oral or motor stereotypic behaviors and those without. Similarly, other research teams (e.g., Pell and McGreevy 1999, Clegg 2008, Hemmann 2012) reported no differ-ence in blood plasma cortisol levels between cribbers and noncribbers. STACEY NEDROW-WIGMORE/ARND.NLTheHorse.com|The HorseNovember 201913CribbingColic USE2.indd 13 9/25/19 10:43 AM'