Scientists have finally discovered why horses have such long faces.
Researchers found that the animals get the winter blues and could suffer from some form of Seasonal Affective Disorder or Sad.
The condition, which is caused by lack of sunlight, is thought to be triggered when horses are kept stabled for long periods.
The study at Nottingham Trent University compared the feelings of depression, lethargy and insomnia felt by human Sad sufferers with the behaviour of horses in unnaturally dark conditions.
Half of the animals at Brackenhurst Equestrian Centre were given light treatment therapy - one of the most effective treatments for Sad in humans.
The treatment involved the horses standing under specially-designed light strips (Brite-boxes) for an hour a day for six weeks.
Those taking part in the study were assessed on various aspects of their behaviour before and after the light treatment therapy.
Their sleep …