Doggies in the dumps as now even our pets are suffering from the winter blues

But, as with their owners, it seems even the brightest Bonzos and the friendliest Fidos are likely to become a little down in the mouth as winter approaches.

Vets believe that not only do dogs and cats suffer from what is called Seasonal Affective Disorder in people, they also echo humans in turning to comfort food to beat the symptoms of fatigue and depression.

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According to a survey by leading veterinary charity PDSA, as many as one in three dog owners see a considerable downturn in their pets' moods during the winter months.

And half of owners felt dogs slept for longer, with around two in five reported to be less active.

One in three cat owners also stated that their pet seems "sadder" and less playful during winter.

Experts reckon the poor weather this summer could mean many owners have already begun noticing the signs of seasonal depression in their animals.

"When considering our pets in this context, it's fair to say that the very poor summer we've had and the onset of dark nights, could certainly have an impact on our pets' mood," PDSA senior veterinary surgeon, Elaine Pendlebury said.

"So, owners need to kick-start their pet's winter health routine with regular exercise and a well-balanced diet."

Five million adults in Britain are known to experience some form of the disorder, ranging from social withdrawal or gloomy moods to intense bouts of depression.

Scientists understand that SAD in humans is caused by low levels of light that lead to a chemical imbalance in the part of the brain that controls body functions such as sleep, appetite, mood and activity.

And experts now believe the same process can affect animals in the same way.

"The cause of SAD in people is thought to be linked to the levels of melatonin in the body," said Miss Pendlebury.

"The production of this hormone is inhibited when light hits the eye's retina. Therefore more melatoninis produced when it is dark, which is why it is also called 'the hormone of darkness'.

"When this hormone is released into the bloodstream it is thought to make us drowsy and a little down in the dumps."

Sufferers are usually filled with aching tiredness, feelings of despair and even develop cravings for unhealthy comfort foods such as cakes, biscuits and chocolate.

And the same effects could also be a problem for our pets as they turn to food to battle the winter blues.

One in four cat and dog owners surveyed revealed their pet's appetite increases in the winter.

In an effort to reverse the symptoms experienced by unhappy pets, Miss Pendlebury suggested continually talking to and comforting animals and playing games such as hiding favourite toys to keep them active.

She said: "Of course, the change in our pet's mood may be simply due to cold weather and fewer opportunities to stretch their legs outside, but diet and exercise can play a big part in perking up your pet."

But puppy love could be a cure

Max is a typically affectionate and energetic two-year-old spaniel.

But his owner Carly Evans, 30, noticed a downturn in his behaviour last year.

As it became darker outside, she found Max, a cavalier King Charles cross, became far less playful.

"He was so lethargic and there was just no reason for it." said Miss Evans, from Essex. "I then found out that other dog owners had similar problems.

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"There are lots of people who laugh and think you are being over-protective.

"But we really make the effort to get him out whenever we can. He also gets much more treats than he would normally, and we find that by chasing him round the house and giving him lots of cuddles can really keep his spirits up."

And if that doesn't work, Max now has a puppy for company.

Miss Evans said: "We decided to get Grace as a playmate for him. Max really loves her.

"He is already chasing her round the garden and looking very sprightly. In January and February he can become very inactive and lazy.

"We just thought having some company might spur him on."