Dogs left alone at home feel just as much isolation as children abandoned by their parents, a new study suggests.
Although many dog owners leave for work and lock their pets in the house without a second thought, evidence suggests the experience may be more traumatic than they realise.
Rather than spending the day curled up in an armchair or stretched out on the bed, some dogs suffer from acute desperation and distress when left to their own devices.
John Bradshaw, directors of the Anthrozoology Institute at Bristol University, who has studied pet behaviour for 25 years, said the situation represented a "real and ongoing crisis" for dogs.
Dr Bradshaw and his team put video cameras in the homes of 20 dog owners, all of whom claimed their pet was perfectly happy being left at home while they were at work.
In fact some were shown treading in circles around the doormat, while breathing heavily and whining, and one dog's trauma was such that it had to be referred to an animal psychologist.
A separate study of seven litters of labrador retriever puppies and five families of border collie puppies found that more than half the labradors and almost half the collies exhibited signs of separation distress which lasted for longer than a month and peaked at about one year of age.
In his book, In Defence of Dogs, to be published this month, Dr Bradshaw describes how his black labrador, Bruno, used to chew on his bed, the furniture and the wallpaper when left alone in the house.
In more extreme situations dogs experiencing separation distress can resort to self-mutilation, he said.
However, Dr Bradshaw warned owners not to punish their dogs for the damage they do when left alone – because they will not understand why they are being told off.
He said: "They have a different kind of memory.
"They are not good at reasoning. They cannot think back and realise what they did an hour ago is the reason their owner is cross with them."
The key to helping your dog to cope with being left alone, he said, is to teach it that seeing you leaving the house results in a positive outcome.
This can be achieved by popping back after a short period to give it a treat or some attention, then slowly increasing the length of absence until the dog can be left alone all day.