Why does a horse bite? Causes and how to respond
A bite rarely comes out of nowhere.
Most often it is driven by pain, fear, frustration or a habit the horse has learned from people.
We explain how to recognise the cause and what to do to stay safe.
- Biting is a signal, not a sign of “bad character”. Rule out pain first, especially if the change came on suddenly.
- A horse that bites when the girth is done up may have gastric ulcers, an orthopaedic problem or a poorly fitting saddle.
- Horses quickly learn that a threat can make a person back off. Hand-feeding treats was not found to cause biting.
- Don't hit a horse for biting. Punishment teaches fear of people, not calmness.
A horse bite hurts, and it is easy to think that the horse is being nasty or “dominant”. Research on horse behaviour shows something different: biting is usually a response to a specific situation. It is the horse's way of saying that something hurts, that it is afraid of something, that it is missing something, or that it has learned this behaviour from us.
The good news: once you find the cause, it can usually be removed. Below we describe the most common ones, each with a reference to the research.
First a warning, then the teeth
Horses have rich body language, and a bite is usually the end of a whole sequence of signals. Researchers who catalogued horses' behaviour in conflicts describe the bite threat separately: ears laid back and neck stretched out, without contact with the other animal[1]. Only when the warning doesn't work do the teeth come into play.
Reading these signals carefully is one of the simplest ways to have fewer accidents around horses. A review of research on the human-horse relationship points the same way[2].
The most common causes of biting
Pain and discomfort
Horses with serious spinal problems were clearly more likely to react aggressively towards people[3]. A horse that has started biting “out of the blue” needs a veterinary examination first, not training.
Saddling and the girth
Among 37 horses referred to a clinic for girthiness, the most common diagnosis was gastric ulcers (12 horses), followed by orthopaedic problems (10) and other conditions. In 3 horses, a poorly fitting saddle was to blame[4].
A habit learned around people
Horses quickly learn that a threat can make a person back off[5]. And treats? In a questionnaire study, hand-feeding was associated with licking hands and searching clothes, but not with nipping or biting[6].
Play and youth
Nipping and biting are among the behaviours young horses use to invite each other to play and to play together[7]. With a person, however, the same game is dangerous.
Mutual grooming
Horses groom each other with their teeth. Scratching a horse's favourite spot at the base of the neck lowers its heart rate[8]. When you scratch it, the horse may want to “return the favour”, just as it would with another horse.
Frustration and living conditions
Being stabled encourages, among other things, aggression towards people. Free movement, contact with other horses and frequent access to forage make the biggest difference[9].
horses with serious spinal problems reacted aggressively towards people in standard behaviour tests. In horses with no such changes or only minor ones, there was no such link[3].Fureix et al., PLoS ONE, 2010
Horses hide discomfort when someone is nearby. In a study of horses after orthopaedic surgery, behaviours indicating discomfort decreased by an average of 77% during a carer's visit[10]. That is why a horse can look healthy at exactly the moment you are looking at it.
When does it bite? A table to help you find the cause
The situation in which the horse bites tells you the most. Note down when it happens and compare it with the table.
| When it bites | What may be behind it | Where to start |
|---|---|---|
| When saddling and doing up the girth | Gastric ulcers, an orthopaedic problem, a poorly fitting saddle[4] | The vet, and a saddle fit check |
| When one particular spot is touched | Pain or discomfort in that spot[11] | Examine the spot; if it happens again, call the vet |
| When a threat makes a person back off | A learned habit: the horse knows it works[5] | Safe positioning from the start, reward calmness |
| In the stable, when the horse spends a lot of time there | Frustration, too little movement, company and forage[9] | More hay, turnout, the company of other horses |
| In play, a young horse | Play and testing boundaries[7] | Play with other young horses, calm boundaries with people |
| Suddenly, in a horse that didn't bite before | Pain or illness[3, 10] | The vet, before you start working on the behaviour |
How to respond when a horse bites
- Stay safeStand at the horse's shoulder, not directly in front of its head. Then you don't have to jump away at the last moment, and the horse doesn't learn that the threat works[5].
- Rule out painIf the biting started suddenly or only happens when saddling, start with the vet and a saddle fit check[4]. Training won't remove a cause that hurts.
When to call the vet
- the horse has started biting suddenly or clearly more often than usual,
- it bites when being saddled, when the girth is done up or when its belly is touched,
- it looks round at its belly and nips the area behind the elbow, especially when eating[13],
- the change in behaviour is accompanied by a poorer appetite, weight loss, lameness or reluctance to work.
Frequently asked questions
Should a horse that bites be punished?
No. Punishment has well-documented side effects, and a horse can remember fear after just one incident[5]. Removing the cause and rewarding calm behaviour works better.
Why does a horse bite when the girth is done up?
Most often because of pain or discomfort. In a study of 37 such horses, the most common diagnosis was gastric ulcers, followed by orthopaedic problems and other conditions, and in 3 horses a poorly fitting saddle[4].
Do treats teach a horse to bite?
A questionnaire study did not confirm this. Hand-feeding was associated with licking hands and searching clothes, but not with nipping or biting. Clicker training, in which food is a reward for a specific behaviour, was not associated with any of these behaviours[6].
A foal nips. Will it grow out of it?
Nipping is a natural part of young horses' play[7]. Ideally, a foal plays with other youngsters and learns calm boundaries with people, without punishment.
Scientific sources
We checked every publication in the Crossref and PubMed databases. The numbers in the text link to the list, and the DOI links lead to the original articles.
- McDonnell SM, Haviland JCS. Agonistic ethogram of the equid bachelor band. Applied Animal Behaviour Science. 1995;43(3):147-188. doi.org/10.1016/0168-1591(94)00550-x
- Hausberger M, Roche H, Henry S, Visser EK. A review of the human–horse relationship. Applied Animal Behaviour Science. 2008;109(1):1-24. doi.org/10.1016/j.applanim.2007.04.015
- Fureix C, Menguy H, Hausberger M. Partners with Bad Temper: Reject or Cure? A Study of Chronic Pain and Aggression in Horses. PLoS ONE. 2010;5(8):e12434. doi.org/10.1371/journal.pone.0012434
- Millares-Ramirez EM, Le Jeune SS. Girthiness: Retrospective Study of 37 Horses (2004–2016). Journal of Equine Veterinary Science. 2019;79:100-104. doi.org/10.1016/j.jevs.2019.05.025
- McLean AN, Christensen JW. The application of learning theory in horse training. Applied Animal Behaviour Science. 2017;190:18-27. doi.org/10.1016/j.applanim.2017.02.020
- Hockenhull J, Creighton E. Unwanted oral investigative behaviour in horses: A note on the relationship between mugging behaviour, hand-feeding titbits and clicker training. Applied Animal Behaviour Science. 2010;127(3-4):104-107. doi.org/10.1016/j.applanim.2010.08.008
- McDonnell SM, Poulin A. Equid play ethogram. Applied Animal Behaviour Science. 2002;78(2-4):263-290. doi.org/10.1016/s0168-1591(02)00112-0
- Feh C, de Mazières J. Grooming at a preferred site reduces heart rate in horses. Animal Behaviour. 1993;46(6):1191-1194. doi.org/10.1006/anbe.1993.1309
- Ruet A, Lemarchand J, Parias C, Mach N, Moisan MP, Foury A et al. Housing Horses in Individual Boxes Is a Challenge with Regard to Welfare. Animals. 2019;9(9):621. doi.org/10.3390/ani9090621
- Torcivia C, McDonnell S. In-Person Caretaker Visits Disrupt Ongoing Discomfort Behavior in Hospitalized Equine Orthopedic Surgical Patients. Animals. 2020;10(2):210. doi.org/10.3390/ani10020210
- Torcivia C, McDonnell S. Equine Discomfort Ethogram. Animals. 2021;11(2):580. doi.org/10.3390/ani11020580
- Starling M, McLean A, McGreevy P. The Contribution of Equitation Science to Minimising Horse-Related Risks to Humans. Animals. 2016;6(3):15. doi.org/10.3390/ani6030015
- Torcivia C, McDonnell SM. Behavioral Signature of Equine Gastric Discomfort? Preliminary Retrospective Clinical Observations. Animals. 2025;15(1):88. doi.org/10.3390/ani15010088
Published . This article is for educational purposes and does not replace an examination by a vet.
