ribbing or crib biting is an abnormal, compulsive behavior or stereotypy seen in some horses, and considered a stable vice. It involves the horse grabbing a solid object such as the stall door or fence rail with its incisors, then arching its neck, pulling against the object, and sucking in air.[1] Windsucking is a related behavior whereby the horse arches its neck and sucks air into the windpipe without needing to grab a solid object. Windsucking is thought to form part of the mechanism of cribbing, rather than being defined as an entirely separate behavior.[1] Cribbing and windsucking have been linked as a causal effect to colic and stomach ulcers.[2]
A similar but unrelated behavior, wood-chewing or lignophagia, is another undesirable habit observed in horses, but it does not involve sucking in air; the horse simply gnaws on wood rails or boards as if they were food.[3]