Dogs in northern Britain are more likely to suffer from an illness that stops their tails from wagging, according to researchers.
A team from the Roslin Institute and Royal School of Veterinary Studies in Edinburgh discovered a geographic disparity in erect tail dysfunction.
The phenomenon known as "limber tail" can cause a dog's tail to become limp and difficult to move.
Experts think a colder climate or swimming could be a factor.
The condition is known to affect larger working breeds, such as Labrador retrievers.
Dr Carys Pugh, one of the researchers, said: "It's a condition that's been known about for a long time, but has been actually quiet underestimated.
"What happens is the dog's just tail hangs incredibly limply, or it may be a little bit stiff close to the body and then hang really limply, and it lasts on average three or four days and during that time the dog might be in quite a lot of pain."
Dr Pugh said it can affect some breeds more than others.
"We were studying Labrador retrievers but you can actually see it in labs and golden retrievers, pointers and a lot of the larger, active breeds." she said.
"The internet is full of anecdotal evidence that suggests that swimming might be a cause, and that is something we did investigate, and we found that dogs that were swimming were more likely to develop the condition.
"It might be genetics, but we found the further north they were the more likely they were to get it and if they swam the more likely they were to get it."
The study found evidence that cold conditions could be behind the illness, but researchers said it needed further investigation.
The chance of a dog developing the condition rose by 50% for each additional degree of latitude further north.
Owners were asked how much pain they thought there dog was in on a scale of 1 to 10, and most said it was around 6.
The symptoms usually clear up within a few days, but worried dog-lovers are being advised to take their pet to a vet if they are in a lot of pain.