Cribbing is a sterotypical behaviour, meaning it is repetitive, persistent, and abnormal. There are also other oral stereotypies, including windsucking and wood chewing.
A long time ago, cribbing used to be called a ‘vice’ and was regarded as a plague in the barn that could be ‘caught’ by other horses. We know now that this is not true.
Then it was hypothesized that poor or unnatural living conditions were the cause of cribbing and other oral stereotypies. This is not far from the mark.
Recent research however is showing that horses displaying oral stereotypical behaviour actually have a different neural phenotype when compared to ‘normal’ horses that affects how dopamine interacts with the basal ganglia of the brain. This situation is brought about by stressors during development.
Therefore, the genetics of the horse and the stressors the horse experiences combine to create the stereotypical behaviour.
The Negative Implications of Cribbing
Horses that crib destroy fencing and anything else they can get their teeth on. Stable managers have tried many creative solutions to prevent their barns from being eaten down. Leaving a designated spot that the horse is ‘allowed’ to crib may be beneficial, as it is the horse’s way of coping with the altered dopamine transmission in the brain.
Teeth suffer more wear and tear in the cribbing horse, but with adequate and potentially more frequent veterinary dental care, this drawback can be managed.
To anyone who doesn’t know the causes in the particular horse, the sight and sound of a cribbing horse can be distressing. Being able to explain the phenomenon with sensitivity to a layperson is a beneficial skill.
Because cribbing arises from stressors, the moment someone notices a horse cribbing that doesn’t usually crib, taking a serious look at its environment and making some changes could eliminate the behaviour and improve the horse’s welfare.
Common stressors in horses include social isolation, insufficient time spent foraging, lack of necessary nutrients, and inconsistent handling.
Ensuring that stressors are reduced as much as possible may reduce the horse’s drive to find other ways to cope.
The Positive Implications of Cribbing
If your horse cribs habitually, there is no need to despair. There are also positive aspects of the neural phenotype responsible for the behaviour!
Horses that crib form stronger habits more quickly. They will move from Response-Outcome learning to Stimulus-Response learning more quickly than the typical ‘normal’ horse. This has implications for the effectiveness of classical conditioning, because regardless of the outcome of the behaviour, the stimulus or cue will continue to produce it. Therefore, even if a new rider continually loses balance and pulls on the horse’s mouth during a jumping effort, effectively punishing it, if the habit of jumping on cue is established the horse will continue to do so, regardless of the unintended punishment.
Cribbing horses are also less sensitive to delays between the response and the outcome. This means a reward for correct behaviour doesn’t have to come right away for them to still make the connection and learn or retain the behaviour. Therefore, even if a new rider delays the release of the reins until after the horse has already stopped, the horse will continue stopping on cue in spite of the delayed reward.
Is it any surprise, given all of these characteristics of the crib-biting horse that every lesson barn has one or two (or more) horses that crib? Being persistent in their habits means these horses aren’t untrained by all of the new riders they teach every day. They are less frustrated by inconsistent timing of rewards for proper behaviour, and aren’t put off by inadvertent punishment that comes from inexperience.
Horses that perform stereotypical behaviours have excellent perseverance. These strong habits can create excellent, reliable horses.
Parker, MO (2008) “Behavioural Correlates of the Equine Stereotypy Phenotype”, University of Southampton, School of Psychology, PhD Thesis