last revised April 14, 2017.

Olfactory investigation in the harem social behavior context is often observed as prolonged olfactory engagement of a female and her foal in a bonding regimen. This also may include licking and nudging.1

Bonding is a term we use to describe the development of a close attachment — between romantic partners or close friends or between parent and child or between you and your horse.

There is one thing that all of our husbandry can’t change: horses love each other, just as elephants love each other and deer love each other. Horses can’t get enough of each other. They would be close together in a herd every minute of the day, given a choice. I was especially struck by this in driving across Wyoming, where a pasture can often be 100 acres or more. Survey such a pasture, and find who lives there: a half dozen or so horses. And where are they? Jammed together in one place or another, so close that one tail can swat the flies on a friend’s body. Horses never live alone in the wild,2 and should never be forced to live alone in captivity.

Affiliative behavior is most often seen through allogrooming and play. Its likelihood is affected by familiarity and kinship. Kinship affects familiarity, and it turns out that familiarity is more powerful than kinship in determining affiliation.3 A clever mechanism works to prevent inbreeding: rather than maintaining knowledge of kinship, fillies prefer to join bands with familiar mares but unfamiliar stallions, and colts seem to prefer bands with unfamiliar stallions.4 Of course, when horses are assigned to a pasture, they have no opportunity to choose between herds, but only from within a herd.

Bonding, Food, and Touch

We know primates best. In primates, it seems, touch has great meaning, and is very important in bonding. But interactions involving both contact and food may be even more important in bonding than touch alone. Perhaps due to the magic of oxytocin which swirls through a mare when she feeds her little one, she feels great love for her foal. When breastfeeding comes to an end, foal and mom become much more independent.

Horses Make Out

Yesterday Bud and I had a great ride through the woods, he scored about 10 sliced carrots in our time together and seemed equally pleased with our encounter. At the end of everything, he used his lips to play with my hand. A mule can get a lot of hand in his mouth, and I wondered how many fingers I’d have left. But I never felt a tooth, and walked away certain that all I was feeling was his love. We had made out.

In humans, kissing releases neurotransmitters that improve mood and increase sexual desire5. Horses don’t use our exact kissing techniques, but it does not take much imagination — or any science at all — to know that a horse’s mouth is very sensitive to touch, and know that horses make frequent use of their mouth when interacting with each other. Horses sometimes lick others (or us), routinely rub each other with their mouths, and sometimes offer gentle toothless nibbles of affection. Sure they make out.

Pair-bonding among juveniles within a band is also a common harem social behavior. In this example, female foals are closely engaging each other, which is thought to facilitate development of the female-female ethological relationships critical to band structure and stability later experienced as reproductive members of a family group.6

Bonds between Horse and Human

A horse has limited opportunities to interact with humans. Some of these experiences are certainly positive, but some are likely aversive. A horse must be caught and restrained for vaccination, for farrier and vet visits, and for transport. In all of these situations the human is salient, and the pressure for efficiency make the time together even less pleasant for Mr. Horse. My vet tells the story of how she was once asked to judge at a Pony Club event. All of the horses and their young riders were arranged in a circle when she walked in. Suddenly, ponies began bolting, and riders went flying. These ponies knew one of the best vets in the solar system, and chose to not spend any unnecessary time with her.

I do not blame vets and farriers for the bad feelings that a horse can develop about humans. If a horse won’t stand for shoeing, he must be shoed anyway. But do the math: the more unpleasant experiences a horse has with humans, the more he’ll need offsetting positive experiences to build and maintain his positive attitude toward humans.

Humans can have a huge effect. In a study of one-man pig farms in the Netherlands, the fearfulness of the animals accounted for 40–60% of the variance between farms in farrowing rate and for 29–36% of the variance in total number of piglets born.7 Another study in the Netherlands found that 30-50% of the variance in milk production per cow was determined by the fearfulness of the cows toward the human managing them.8 The behavior of farm staff can have powerful effects on their charges, and — by extension — powerful effects on your bond with your horse.

If your horse resists your hugs, he tells you that this proximity makes him uncomfortable. You’ll need to get to work changing that. A relaxed horse in love will let you hug him all over, scratch him all over, rub the goop out of the corners of his eyes, and comfortably stand up close behind him. My horse especially loves to get his face rubbed with a towel. I take the ends of the towel, press it against his nose, and scrub left and right. As I do, he bobs his head up and down. Its not quite like making out when we were young. It’s much better.

Head Start

Researchers in France9 were interested in whether a foal’s mother would influence his relationship with humans. To test this, 21 mares were softly brushed and fed by hand during the first 5 days of their foals’ lives. In this condition, the foals observed their mother interact with the human for only an hour and 15 minutes. In a control condition, 20 mares with foals were not handled by the experimenter. In neither condition did the experimenter interact with the foals.

Evidently the foals were paying attention to what was going on with mom. Those who observed mom being brushed and hand fed came closer to the experimenter than the others, regardless of age. They initiated more physical contacts with the experimenter, such as sniffing and licking; they showed fewer avoidance and flight responses than the others, and they accepted saddle pads on their backs more quickly and easily. These positive effects lasted for the entire first year of these foals’ lives (the time that measurements were made), and generalized from the experimenter to unfamiliar humans, who could approach and stroke these foals rapidly during a test.

We must realize that the evil that men do lives after them, and the good is often interred with their bones. If a horse is mistreated early in life, it will quite likely become reactive — showing fearfulness and avoidance where other horses remain calm and approach a handler. Reactivity might be desirable in a race horse — we would like them to jump out of the gate in terror, and run for their lives — but reactivity makes a horse difficult and sometimes dangerous to handle and ride.10 Because reactivity can be instilled very early in life, and because it is likely to remain constant over a horse’s life, some consider it a temperament trait.11

Foals are like the young of other species who care for their offspring. Mom teaches little, but through observation of mom, the little ones learn much. You won’t find mama bear at the front of the classroom, but her little ones tagging along in the scenery will study her carefully, and learn many things. Foals are like little bear cubs.

Early handling is much more efficient in building trust between foal and human. For instance, one study showed that foals handled daily from day 2 to day 24 after birth performed a halter-training task better than foals who were handled later in life.


1 image source: Ransom, Jason I., and Brian S. Cade. “Quantifying Equid Behavior–A Research Ethogram for Free-Roaming Feral Horses.” U.S. Geological Survey Techniques and Methods 2-A9, 23 p. (2009)

2 Feh, Claudia. “Relationships and communication in socially natural horse herds.” The domestic horse (2005): 83-93. ; McCort, William D. “Behavior of feral horses and ponies.” Journal of Animal Science 58, no. 2 (1984): 493-499.

3 VanDierendonck, Machteld C., and Berry M. Spruijt. “Coping in groups of domestic horses–Review from a social and neurobiological perspective.” Applied animal behaviour science 138, no. 3 (2012): 194-202.

4 Monard, A.M., Duncan, P., 1996. Consequences of natal dispersal in female horses. Anim. Behav. 52, 565–579.

5 Castleman, Michael. “Kissing.” The International Encyclopedia of Human Sexuality (2015).

6 image source: Ransom, Jason I., and Brian S. Cade. “Quantifying Equid Behavior–A Research Ethogram for Free-Roaming Feral Horses.” U.S. Geological Survey Techniques and Methods 2-A9, 23 p. (2009)

7 Hemsworth, P.H., Brand, A., Wilems, P., 1981. The behavioural response of sows to the presence of human beings and its relation to productivity. Livestock Prod. Sci. 8, 67–74.

8 Hemsworth, P.H., Breuer, K., Barnett, J.L., Coleman, G.J., Matthews, L.R., 1995b. Behavioural response to humans and the productivity of commercial dairy cows. In: Proceedings of the 29th International Congress of the International Society for Applied Ethology, pp. 175–176.

9 Henry, Séverine, D. Hemery, M-A. Richard, and Martine Hausberger. “Human–mare relationships and behaviour of foals toward humans.” Applied Animal Behaviour Science 93, no. 3 (2005): 341-362.

10 Hausberger, M., Roche, H., Henry, S., Visser, E.K., 2008. A review of the human–horse relationship. Appl. Anim. Behav. Sci. 109, 1–24.

11 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, no. 3 (2008): 492-508.


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