Why is my horse so mouthy?

Last revised April 24, 2017

This might be a mouthy horse, or just one who enjoys my sense of humor.1

A mouthy horse is one who uses his mouth to grab more than you’d like. A mouthy horse might play with his lead line, your hat, or a stick he found in his pasture. Some people consider horses that bite to be mouthy.

The Role of Hand Feeding

Feeding horses by hand is regularly claimed to be the cause of mugging, nipping and biting. This is a claim made by writers of horse books and magazine articles, by trainers and clinicians, and by those who’ve been exposed to this traditional view.2 Such views lead to conflict with those who see hand-feeding as a means of building the bond between horse and human3, with those who use bridge (clicker) training,4 and with the carrot industry.

If hand-feeding leads to mugging, then mugging must be very common, because hand-feeding is common. In a survey5 of over 1,000 horses in the UK, 91% were sometimes fed by hand. Across all horses surveyed, 81% sometimes gently searched clothing, 77% sometimes licked hands, 24% sometimes roughly searched clothing, 22% sometimes bit clothing, and 21% sometimes nipped hands. So hand feeding, some form of mugging, and some form of nipping or biting were common in this study. The study examined the association between hand feeding and these various horse behaviors, and found an interesting result: hand feeding was associated with licking hands, gently searching clothing, and roughly searching clothing, but not with nipping hands or biting clothes. That is, a horse that is sometimes hand-fed may mug, but will not nip or bite. The authors conclude “These findings suggest that horse owners should not be deterred from using food-based positive reinforcement techniques with their horses, as fears that this practice will result in unwanted oral investigative behaviors from their horses appear unfounded.6

The study also had important findings for those concerned about the effects of bridge training on mugging, nipping and biting. No statistically significant associations were found between the frequency the respondent used bridge training with their horse and the performance of any of the five oral investigative behaviors. The authors conclude that “The lack of associations between any of the five oral investigative behaviors and the use of bridge training suggests that fears over using food rewards to train horses in this manner are misplaced and owners should not be discouraged from using food-based positive reinforcement techniques to train their horses… The study findings do not support anecdotal claims of a relationship between nipping or biting behavior by the horse and hand-feeding or their use as a positive reinforcer during clicker training.7

When I first met my horse, the humans who knew him warned me that he was “mouthy”. Mouthy apparently means that he uses his mouth to explore the human who is walking with him. I wasn’t sure why this was a problem: he doesn’t have hands, he can’t talk, but why can’t he be physically affectionate or curious with his mouth? After all, he was exploring me by pressing his nose against me, or touching me with his lips. His mouthiness has continued over the past decade, and I know that with me, he uses it to express his trust and affection. Yesterday in the barn, he licked my entire barn coat clean — while I was wearing it.

In this section, I will cover three things a horse might do with his mouth: nibbling, mugging, and biting.


Nibbling is done with the lips, not the teeth. Nibbling is not a bad behavior. Horses nibble. Nibbling is a central theme in positive social interactions that horses have with each other and with us. It is also an exploratory behavior that may be displayed when Mr. Horse faces a novel but not fear-inducing object.8 In a study comparing clicker training to traditional negative reinforcement training techniques,9 nibbling of a human only seems to occur of the experimenter’s arms, and only seemed to happen where there was no food in the experimenter’s pockets. In another study,10 results indicate that the more frequently a horse sniffed, licked or nibbled a passive human, the easier it was for either a familiar or unfamiliar active human to touch and halter it. Moreover, a horse which could be touched easily by a familiar human could also be touched and haltered easily by an unfamiliar human. These studies suggest that nibbling is one of the most stable parameters of a ‘‘reactivity to humans’’ temperament trait.

Perhaps the most important study bearing on the topic of mugging and nibbling has found that nibbling did not lead to biting. These researchers found more than 5 times less biting in young horses trained with food reinforcement than in controls, and four to six times less aggressive behaviors overall,11. In any case, horses can also learn not to nibble if it is the trainer’s wish, but it remains, together with other parameters, an interesting indicator of contact seeking.

Supporting this notion are studies in which human contact reduced the animal’s fear of humans and improve handling ability, even when the human was associated with food.12 In these studies the positive feelings about humans cannot be attributed to the presence of ‘‘tools,’’ as the animals’ reactions to humans were tested without food rewards.

In summary, nibbling must be seen as a sign of affection, not of aggressiveness. And it is a good sign, because a horse that nibbles will be easier to approach, halter, and work with.


Mugging is done with the entire head, reaching for food. Mugging may be a bad behavior — some folks are more offended by it than others — but is easily stopped. When we accuse a horse of mugging, it has been reaching for food, or reaching for where it suspected food might be. A mugging horse might lick your hand, feel your hand with his lips, search your clothes, or try to reach into your pocket. If you have treats in a pouch, the mugging horse may try to open the pouch to extract a treat. Mugging may be considered a bad behavior because a horse is so big, and assertiveness from someone this size can be intimidating. For anyone who has issues with “personal space” and does not want to be touched by a horse, mugging is a bad behavior. And mugging is a bad behavior if you are an old barn coat, ready to give way. Frankly I’d rather be mugged by a horse than a lion.

When a horse mugs, he is telling you how incredibly important your treats are to him. All we need do is teach him that he can have those treats by doing what we want, and can’t have them by simply demanding them. If he’s willing to play the ukulele to get a treat, why shouldn’t we all have a little music with our dinner?

Mugging happens because of your own bad behavior, and is quickly changed by a subtle change in your own behavior.

The horse that mugs has learned that when he demands a treat through mugging, that the treat is sometimes forthcoming — perhaps not immediately, perhaps not always, but with enough likelihood that it is worth the trouble of mugging. The mugged horseman may withhold the treat, and resist for several minutes, during which time they are mauled. Finally, to stop the mugging, they give in and deliver a treat. The horse has just been given a reward for the behavior that just occurred: persistent mugging. When we alternate between sometimes withholding a treat when mugged and sometimes yielding and providing a treat when mugged, we are training mugging using a partial reinforcement schedule: providing a reward after an unpredictable number of responses. Partial reinforcement is very effective in maintaining a high, steady response rate13 of mugging or any other behavior.

To stop mugging, you simply need to extinguish it. When an operant behavior like mugging is reinforced, it becomes more likely. When the reinforcement is withdrawn, it becomes less likely. Extinction14 occurs fairly quickly, if the reinforcement is withdrawn and is never delivered when the bad behavior occurs. So the burden is on you. You must decide that you, and only you, decide when your horse gets a treat. You must decide that he will never get a treat if he mugs. And you must follow your rule 100% of the time. Just one or two occasional violations of your promise will put him back on a partial reinforcement schedule, teach him that mugging sometimes pays off, and he’ll be back to it.

If you are getting mugged during bridge training, then leave the treat in your pouch or pocket, and hold only the clicker in your hand. Consider moving your pouch around toward your back side, so that it is harder for your horse to reach. Then, when he meets your objective during training, give him a click and praise and then reach for your treat. You must deliver the treat to your horse’s mouth, and not let him retrieve it from your pouch.

If you are training a horse that is very aggressively mugging, you may want to do your initial training from the other side of the round pen or some other barrier. The first trick you’ll want to teach is how he should behave around food. You can do any simple training from the other side of the fence, such as target training. During the training, be extra careful to not reward mugging, and only ask for the trick when he is quiet, only reward with a click, praise, and treat when he has not mugged. Once this seems to be working, try entering the pen with your treat pouch zipped closed. Spend time grooming him but do not give him a treat unless he is standing very quietly, and is not mugging.

When I greet my mule or horse after entering the barn, I am likely armed with a pouch full of carrots. My hand likely smells like carrots. I reach into their stalls with my empty hand and let them smell me, as part of our greeting ritual. Sometimes they use their lips on my hand, to double check for carrots. Finding none, they stop their search and stand quietly. Mugging simply doesn’t happen, because I only give them treats when they have not asked.

Nipping and Biting

Nipping and biting are done with the teeth. Nipping and biting are definitely bad behaviors. Nipping and biting hurt and are aggressive behavior. It may be done playfully (as in rough horseplay) or with belligerence, but regardless of intent, nipping and biting are unwanted behaviors that produce painful results.

Nipping and biting are very different behaviors than mugging or nibbling. Nibbling is done with the lips, and is as soft as a kiss — because that is what it is. Mugging is investigative behavior, is a natural exploratory or food-seeking behavior, is not done with the teeth, and causes no injury to humans. Nipping and biting are done with the teeth, and typically cause black and blue or more.

While horses that play hard regularly nip and bite each other in good fun, you may not feel so playful. My own horse sometimes tries a nip as a playful prank. When he does, I simply say “NO!” firmly. He always stops and apologizes.

If your horse plays too hard, you’ll need to tip him off that he’s overdoing it. And if he is trying to bite you and hurt you, you may need some therapy before you can go on happily with him. Something you or someone else has done have enraged him, and he’ll need to learn to trust again. I’d stock up with sliced carrots, put on a sturdy barn coat, approach slowly and only on his invitation, and keep your eyes glued on his ears, eyes, tail, and other parts that will tell you of his mood. Only approach when he invites you. If you can stand with him, and if he does not ask for a carrot, give him one. (If he does ask, then no carrots, because you won’t want to reward mugging or begging.) Slice your carrots in advance, so that they’ll go further. You want to start spending happy times with him. You want him to learn that you are fun to be with.


1 Image source: Equus Magazine. “Q&A: How to deal with a “lippy” horse”. Nov 20, 2013.

2 For anecdotal accounts on the relationship between hand feeding and mugging, see Hartley-Edwards, E. “The horseman’s manual: A complete guide to horse management.” JA Allen, London, UK (1990). For advice that hand-feeding leads to nipping and biting, see Auty, I. “The British Horse Society Complete Manual of Stable Management.” Kenilworth Press, Addington. (1998) and Dillon, E., and H. Revington. “Show Jumping for Fun or Glory.” (2000). Kenilworth Press, Addington.

3 A. Pavia, J.M. Posnikoff; Horses for Dummies. Hungry Minds, New York (1999).

4 There is a literature voicing concern that the treats used in clicker training will lead to mugging. See Waran, N., McGreevy, P., & Casey, R. A. (2007). Training methods and horse welfare. In The welfare of horses (pp. 151-180). Springer Netherlands and Hart, Ben. The art and science of clicker training for horses: a positive approach to training equines and understanding them. Souvenir Press, 2011.

5 Hockenhull, Jo, and Emma Creighton. “Unwanted oral investigative behaviour in horses: A note on the relationship between mugging behaviour, hand-feeding titbits and clicker training.” Applied Animal Behaviour Science127.3 (2010): 104-107.

6 Hockenhull and Creighton, op.cit.

7 Hockenhull and Creighton, op.cit.

8 McDonnell S, Poulin A (2002) Equid play ethogram. Appl Anim Behav Sci 78:263–290

9 Sankey, Carol, Marie-Annick Richard-Yris, Séverine Henry, Carole Fureix, Fouad Nassur, and Martine Hausberger. “Reinforcement as a mediator of the perception of humans by horses (Equus caballus).” Animal cognition 13, no. 5 (2010): 753-764

10 Lansade, Léa, and Marie-France Bouissou. “Reactivity to humans: A temperament trait of horses which is stable across time and situations.” Applied Animal Behaviour Science 114.3 (2008): 492-508.

11 Sankey, Carol, Marie-Annick Richard-Yris, Séverine Henry, Carole Fureix, Fouad Nassur, and Martine Hausberger. “Reinforcement as a mediator of the perception of humans by horses (Equus caballus).” Animal cognition 13, no. 5 (2010): 753-764

12 de Passillé, Anne Marie, Jeffrey Rushen, Jan Ladewig, and Carol Petherick. “Dairy calves’ discrimination of people based on previous handling.” Journal of Animal Science 74, no. 5 (1996): 969-974.; Munksgaard, Lene, A. M. De Passillé, J. Rushen, Karen Thodberg, and Margit Bak Jensen. “Discrimination of People by Dairy Cows Based on Handling1.” Journal of Dairy Science 80, no. 6 (1997): 1106-1112.

13 Domjan, M., 2003. The Principles of Learning and Behaviour. Wadsworth/Thomson Learning, Belmont; Lethbridge, E., 2009. Knowing Your Horse a Guide to Equine Learning, Training and Behaviour. John Wiley & Sons Ltd., Chichester.

14 For an overview of extinction as a principle of learning, see


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