Separation Anxiety in Horses: What is Buddy Sour & How to Fix It [Behavior Guide]

Separation anxiety in horses, also referred to as “buddy sour,” is a common behavioral issue that can lead to stress, dangerous behavior, and a decline in overall well being. Horses are social animals, and when separated from their herd, anxiety and frustration can manifest in behaviors like pacing, calling out, sweating, or even attempting to escape.

Buddy sour can be a challenge for even the most experienced horse owners. While caretakers and owners work hard to ensure their horses are comfortable and happy, separating equines from their herd-mates is sometimes unavoidable.

To help manage herd-bound horses, it’s helpful for owners and caretakers to familiarize themselves with the underlying adaptations horses have that drive this behavior.

Read on to learn why a horse might become buddy sour, what this condition can look like, and how to help horses overcome this frustration in a positive manner that promotes their welfare.

Equine Separation Anxiety

It’s a situation many equestrians know well: you’ve decided to take your horse out for a hack on a beautiful day, just the two of you. Just as you start to relax into the ride, your horse begins dancing, calling, pawing or even attempting to turn around and run home. The tension builds until you give up and call it a day, disappointed in your trusty steed.

These unexpected behaviors are discouraging for riders, especially when they seem to come out of nowhere. The good news is, by understanding what your equine companion is trying to say, you can take steps to address it so both of you can enjoy riding together again.

Once you have ruled out a physical cause of your horse’s behavior, it’s time to look at their mental landscape. Horses with sudden behavior issues in a one-on-one setting might have a change in behavior because of separation anxiety.

Horses experiencing separation anxiety are also referred to as “herd-bound” or buddy sour. These are horses who become anxious or frustrated when separated from their friends and herd-mates.

Signs of buddy sour in horses may include: ^[1]

• Calling out to other horses
• Increased spookiness and flightiness
• Attempts to run back to the group when separated

Common Scenarios

Separation anxiety is often challenging for horse owners, as there are many scenarios where separating horses from others is unavoidable, including:

• Riding or working in an empty arena
• Trail riding alone
• Stall rest or long-term stall housing
• Horse shows
• Off-property veterinary visits or hospital stays
• Moving to a new barn
• Emergency evacuations

Understanding separation anxiety will help you better support your horse’s well-being the next time one of these unavoidable situations arises.

Herd-Bound Adaptations & Buddy Sour

Horses are herd animals. They have evolved to rely on their social groups for safety and survival. In the wild, while some horses graze or sleep, others in the group stay vigilant to watch for predators. Long periods of social isolation are rarely seen in wild horses. ^[2]

A horse’s natural instincts signal that being alone is unsafe, which creates a strong motivation to stay close to their social group. This instinct to remain with the herd for protection is what drives feelings of separation anxiety when they are separated.

It may seem like domestic horses don’t need to worry about predators, but it’s important to remember that horses have only been domesticated for about 5,000 years — a much shorter period than animals like dogs, which were domesticated around 30,000 years ago. ^[3][4]

In fact, when kept in natural conditions, domestic horses spend their time very similarly to wild horses. ^[5] Their natural instincts have not changed much in the relatively short time they have lived domestically with humans.

Isolation in Domestication

Many aspects of modern horse management involve keeping horses separated from each other. One of the largest causes of social isolation is stall housing, which often prevents horses from being able to touch or even see each other while stalled.

Research shows how isolation impacts horse socialization and welfare. For example, stall-housed horses experiencing social isolation demonstrated higher levels of vigilance and anxious behavior. ^[6][7][8]

Additionally, studies show that when horses can touch noses or see other horses while in stalls, their levels of vigilance and fear behavior decrease. These results highlight how important the presence of other horses is to the horse’s perception of their own safety. ^[6][7][8]

Anxious Behaviors

A herd-bound or buddy sour horse may demonstrate anxious or frustrated behaviors that range from mild to severe. Milder responses may include: ^[1]

• Resistance to walk away from other horses
• Increased vigilance or spookiness
• Calling to other horses
• Pawing, restlessness or inability to stand still when alone

During periods of prolonged or significant separation anxiety, horses may develop negative effects that can impact their well-being. These can include: ^{[1][9][10][11][12]}

• Stereotypic behavior: Stereotypies, such as weaving, are maladaptive, nonfunctional, and can result in consequences such as repetitive stress injuries, weight loss or uneven hoof wear. Stereotypies are also associated with a higher risk for the development of ulcers and colic
• Self-mutilation or wall kicking: A dangerous behavior that can lead to injury and infection in the horse
• Chronic stress: Long-term stress can result in immune suppression and contribute to the development of ulcers, both of which negatively impact health
• Escape behaviors: These can include bolting, spinning, rearing, charging, and more, and can endanger horses and humans alike

The Nuance of Equine Socialization

Some horses may appear herd-bound even while in the presence of other horses. This is because one equine companion is not interchangeable for another.

Much like humans, horses have preferred social partners that provide a sense of security and calm. For example, social grooming (allogrooming) is a behavior observed in horses that relieves tension and lowers heart rate.

One study showed when under stressful conditions, horses preferred the company of specific friends and demonstrated greater levels of allogrooming with these partners. ^[13]

Once a relationship is formed between horses, they tend to stay in close proximity with their friends and choose to spend time with these friends over other horses. ^[14]

Close relationships between horses can also be long-lasting. One study found that even after 5 months of post-weaning separation, foals preferred the presence of their dam over another familiar mare. In the wild, mare-foal bonds tend to continue well past weaning. ^[15]

Your horse’s social relationships with their herd may influence the level of anxiety they experience when separated from the group. Understanding who your horse’s friends are can help you predict when and how their separation anxiety might flare up.

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Other Factors

Certain horses may be more prone to the anxiety and fearfulness that drives herd-bound behavior. Factors that may contribute to whether a horse gets buddy sour include: ^[16][17]

• Personality/Temperament: Much like humans, horses vary in their natural temperaments, with some horses having more anxious or reactive personalities
• Breed: Certain breed types such as Arabians and Thoroughbreds tend to be more reactive and anxious compared to breeds like Quarter horses and draft horses
• Age: Horses between the age of 11 and 15 may develop increased nervousness following a sale or change in environment
• Horse history: Horses subject to multiple owner changes or a variety of regular handlers tend to be more reluctant when engaging with new or frightening scenarios

Human Bonding & Buddy Sour

As long ago as 350 BC, horsemen suggested that keeping horses isolated from their friends could improve the connection between horse and caretaker, as the horse would view the person as a means of relieving their distress. ^[18]

Creating a system of dependency upon humans cannot address the root causes of separation anxiety, but it is important to understand how a human’s presence can affect a horse’s level of comfort in training and housing.

Humans, Horses, & Anxiety

A horse’s social environment can affect how they engage with humans and how much anxiety they feel when separated from their herd mates.

For example, horses housed in individual stalls without adequate social opportunities to interact with other horses were found to approach humans sooner and were more easily approached by humans overall. ^[19]

Another study found when left alone in an arena, horses sought human attention. When humans were in the arena, these horses demonstrated behavior that suggested a lower state of stress compared to when they were left alone. ^[20]

Horses have also been found to prefer the presence of familiar humans. When given a choice between approaching their owners or an unfamiliar person, horses both approached and spent more time with their owner compared to a stranger. ^[21]

However, it has been suggested that this “safe-haven” effect humans appear to have on horses may be less related to the presence of humans themselves, but rather the fact that these horses were socially isolated before the human arrived. The presence of a human may be less impactful on a horse’s stress level if other horses are already present. ^[22]

Prevention

The first step to helping your horse manage their separation anxiety is to ensure they are receiving appropriate social opportunities in their day-to-day life. Daily turnout with a stable group is critical for promoting equine welfare and enabling natural social behavior.

If your horse is stalled for part of the day, using stalls with grids or windows that allow horses to see and touch noses with other horses can help reduce levels of stress and vigilance. ^[7]

Stalling

Stall rest for medical reasons is sometimes unavoidable, but healthy horses require regular turnout and social opportunities to maintain their welfare. If your horse is on stall rest or otherwise stalled, there are a few things you can try to help ease anxiety: ^[22][23][24]

• Adjust turnout schedules:  Horse owners can change the turnout schedules of other stalled horses so there is always at least one other horse in the barn while others are turned out.
• Provide a visual surrogate: Some research suggests hanging a mirror or photo in your horse’s stall may reduce stereotypies and stress behavior in stalled horses.
• Increase human bonding time: When a horse can’t socialize with other horses, they feel less anxious when a preferred human is nearby. Spending lots of time with a horse on stall rest may help ease their nerves. You can groom them, talk to them, feed them snacks or even just read a book nearby!

Training a Buddy Sour Horse

If your horse is not on stall rest, has appropriate socialization opportunities and is still showing signs of separation anxiety, specific training may be required to help your horse manage this anxiety.

The basic approach to working with a buddy sour horse is:

1. Identify the stress threshold
2. Gradually increase stressors
3. Monitor, reassess, adjust

1. Identify the Stress Threshold

When training a horse to handle a stressful scenario, it is important to stay under their stress threshold – the point at which a trigger becomes an emotional reaction for a horse. A horse’s stress behaviors can be very subtle, and humans often struggle to identify them appropriately. ^[25]

To identify your horse’s stress threshold, look for changes in facial expression and body language. These may include: ^[1]

• Increased tension in the eye and muzzle
• Rigid ears pricked in one direction
• Raised head and neck
• Reluctance to walk forward

2. Gradually Increase Stressors

Once you’ve identified your horse’s stress threshold related to separation, you can work within this range to gradually increase their comfort level. Your horse’s stress might start right at the paddock gate, or it may not be apparent until they’re back in the barn.

While staying under threshold, you can employ counter-conditioning techniques to change the horse’s association with the experience. ^[26] Providing food rewards, wither scratches, a return to companions, or other forms of positive reinforcement can help your horse manage their stress and gradually overcome it at a level where they are comfortable.

Owners may also choose to work with other horses present who are not their horses’ preferred companions. This can provide an intermediate step between comfort and total separation.

3. Monitor, Reassess, Adjust

When dealing with horses with separation anxiety, many owners may unintentionally push their horses too fast because they believe their horse “should” be fine with what is being asked. However, it’s important to remember that horses are not capable of the same kind of logical reasoning that humans are. ^[1] In addition, separating from companions goes against the horse’s biological instincts.

As a horse recovers from a stress response, they may lick, chew or yawn – common oral behaviors that occur as the “fight or flight” response disengages. ^[1] When the horse demonstrates this behavior, you may be able to escalate the task you ask of them again, moving a little further from the herd once more until you find their new threshold.

Keep in mind your response to your horse’s stress behaviors can directly impact training success. When a fear response is reinforced, it grows stronger and becomes more challenging to undo. ^[1]

If a horse perceives separation as a valid reason for fear, the emotional response can grow stronger. This is why it’s essential to remain within your horse’s stress threshold during training.

As with all matters in horse training, there is no one-size-fits-all solution to separation anxiety. If you are struggling to help your horse manage this challenge, consider consulting a qualified equine behaviorist for help.

Frequently Asked Questions

Here are some frequently asked questions about separation anxiety and buddy sour in horses:

Summary

Separation anxiety in horses, sometimes referred to as "herd-bound" or buddy sour, is an emotional state generated by the horse’s natural instinct to maintain safety through the presence of a group. Social isolation cannot always be avoided, but appropriate training can help a horse learn to manage their anxiety in these scenarios, keeping both horses and humans safe.

• Separation anxiety can result in stereotypies, chronic stress and potentially dangerous behavior
• Horses have preferred social companions, whose presence or absence may determine the severity of their separation anxiety
• Breed, personality, age and life experience may predispose a horse to feelings of separation anxiety
• Human presence may help a socially isolated horse deal with their separation anxiety but will not solve the root issue
• Gradual, empathetic and attentive training that stays under the horse’s stress threshold can help a horse learn to overcome their separation anxiety
• A qualified equine behaviorist can help resolve challenges related to separation anxiety