Mystery surrounds 'dog suicide bridge'

And this week we were treated to the most outlandish idea of them all: the bridge-jumping dogs are driven to it by the apparition of a lonely dowager.

This latest theory came about after a photograph emerged of a ghostly whitish figure looking out from an upstairs room of Overtoun House.

“When Baron Overtoun, who built the bridge, died in 1908 she [Lady Overtoun] was said to have wandered the bridge griefstricken for years,” says Glasgow teacher Paul Owens, who has written a book on the mystery.

There is no way my dog did it on purpose, there is something going on here

Alice Trevorrow

“It is thought by some to be her presence that lingers here.” Others invoke the horrific story of 32-year-old Kevin Moy.

In October 1994, believing himself to be the anti-Christ and his two-week-old son to be the Devil incarnate, Moy threw his baby from the bridge to his death.

Alice Trevorrow, a nurse from Dumbarton whose springer spaniel Cassie jumped off the bridge a year ago but survived, is certainly convinced all is not as it should be.

“There is no way my dog did it on purpose,” she said this week.

“There is something going on here. It was so out of character for her.”

Those who do not believe the supernatural is at work have cited depressed owners passing on their suicidal urges, pylons sending dogs haywire and even noises audible only to dogs emanating from the nearby nuclear base at Faslane.

So what is known for sure about the number of incidents on the bridge involving dogs? First reports date back to the 1950s.

All the dogs involved are of long nosed breeds, such as retrievers, which have a strong sense of smell.

The “suicides” typically happen on a clear day.

These factors support a theory put forward by an animal behaviourist called Dr David Sands in 2006.

He noted that the 1950s was the period when minks – introduced into Scotland 30 years earlier – started breeding in large numbers.

Research conducted around the base of the bridge established that mink and mice were both present in the undergrowth and squirrel nests were found in the barrels of cannons embedded in the bridge.

The next step was to find out which of these animals was the most likely to attract dogs.