Why do horses develop separation anxiety?

Separation anxiety is a common behavioural problem in horses. Most yards have a horse who is anxious about leaving the yard or panics when his friend is removed. Why does this happen? And why are some horses affected more than others?

Horses have evolved over millions of years to live in groups - for prey animals there is safety in numbers. They depend on other herd members to alert them to potential danger and to watch over them while they sleep and relax, they need equine company to feel safe. So naturally, horses do form strong attachments and will often form a ‘pair bond’ for life – a close relationship with another horse, often a similar age, height and size to themselves. A horse on his own is in a dangerous situation and must be constantly vigilant – any lapse of concentration could be a matter of life or death.

In contrast, our domestic horses are often turned out in individual paddocks, or in constantly changing herds, never having the opportunity to form these friendships. Some horses understandably become very distressed by the isolation or upheaval, are unable to relax without equine company and tend to cling to others when they do finally have the opportunity to socialise with horses long-term. 

Horses who were weaned at too early an age or had a sudden, traumatic separation from their dam are likely to suffer from separation anxiety later in life. Horses who have been isolated from others for any period of time (box rest is a concern here) or those who have been frightened when separated from their herd may also become fearful of leaving the safety of the group again.

Realistically for a horse to be anxious when alone could be considered normal behaviour. It is our responsibility to ensure our horses are confident if they are separated from others, this needs careful and patient training. The best approach is to change how the horse feels about being alone very gradually, so as to avoid reinforcing their fear. If they have good experiences when separated and the length of time spent apart is increased a little at a time, their confidence will grow and they will realise they will always be returned to their friends and there is nothing to fear.

If your horse is becoming overly attached to another individual, start a gradual training plan to practice short separations of a few seconds at first, then gradually (and carefully) increase the length of time they are apart in subsequent sessions. Ensure both horses have calm, well-socialised equine company and they have a good experience when separated - eg. a feed, a lip-curling wither scratch or food rewards.

Don't force your horse to leave others, leave him on his own or punish him if he is anxious. He will not 'get used to' his fear. Leaving him alone and distressed will only reinforce that he should be frightened when he's on his own and this is likely to make matters worse.

If your horse will be alone for a specific situation e.g. a vet or farrier visit and you think they may struggle, make sure you have another calm horse present. If that isn't possible, ensure your horse has access to plenty of food – a choice of forages and/or feed to occupy him.

In more severe cases it is advisable to employ a qualified behaviourist to help create a step-by-step programme to find the best long term solution.