In 2010, animal behaviorist David Sands visited the bridge and concluded that dogs certainly weren't killing themselves on purpose. He figured that since most of the dogs that jump are long-nosed types with especially keen odor tracking skills, wild animal scent may be a trigger.
Perhaps the dogs can smell or see wild creatures scurrying below the bridge, noted Sands. And maybe the bridge's construction, which has tapered edges, might make it look like a safe, flat plane from a dog's point of view, also contributes to their confusion.
In his documentary about the bridge mystery, Sands says, "I think it's highly likely in all the cases here at Overtoun Bridge that it was curiosity that killed the dog."
Still, this part of the country is full of superstitious folks. Some of them believe that there are paranormal factors at work, driving the dogs to jump to their deaths.
One theory is that a grieving widow, the "White Lady of Overtoun" maintains a ghostly presence at the bridge, stirring the dogs into a death frenzy.
Another, even darker take, harkens to a terrible event that occurred in 1994. It was that year that a 32-year-old father threw his own baby – whom he was certain was the anti-Christ – into the gorge below. The baby died the following day, and the father was declared insane and committed to an institution.
Locals say that dogs, in almost every case, tend to jump from the same spot that the baby was thrown from. Perhaps, they say, the terrible ordeal left a supernatural rift of sorts that affects dog behavior.
Whatever the case, scientists don't seem to believe that dogs are intentionally offing themselves because their Prozac prescriptions ran out. Suicide is more of a creation of the human condition.
Until the mystery is solved, perhaps local dog walkers should consider mandatory leash laws for anyone who approaches the bridge.