A painful condition that affects dogs' tails may be more common than previously thought, a study suggests.
The research offers clues to potential causes of the illness - known as limber tail - which mostly affects larger working dog breeds, such as Labrador Retrievers.
Researchers say their findings are the first step towards preventing the distressing condition, which causes the tail to become limp and painful.
The team at the University of Edinburgh compared 38 cases of limber tail that were identified from owners' reports about their dogs' health with 86 dogs that had no tail symptoms.
Their goal was to gain insight into habits and lifestyle factors that might explain why some dogs are affected and not others.
The majority of dogs in the study were pets but those affected by limber tail were more likely to be working dogs, they found.
Swimming has previously been thought to be a risk factor for limber tail, which is sometimes known as 'swimmers' tail'. Some but not all of the affected dogs had been swimming prior to the onset of symptoms, the study found.
Dogs with the condition were more likely to live in northern areas, lending support to anecdotal reports that limber tail is associated with exposure to the cold.
Labradors that had suffered limber tail were more likely to be related to each other than unaffected dogs, which may indicate an underlying genetic risk.
Experts hope that further studies will identify genes associated with the condition, which could one day help breeders to identify animals that are likely to be affected. Over time, this could help to reduce the disease prevalence.
The symptoms usually resolve within a few days or weeks so many cases are not reported to vets. This may be why it has been so underestimated in the past. However, owners report that it can be very painful and distressing for the animals.
The study is the first large-scale investigation of limber tail and was conducted as part of the Dogslife project, which follows the health and wellbeing of more than 6000 Labradors from across the UK.
Dr Carys Pugh, who led the study at the University's Roslin Institute and Royal (Dick) School of Veterinary Studies, said: "We were surprised by how many owners were reporting limber tail to us but it meant we had the chance to do a detailed investigation.
"We have been able to add evidence to a lot of internet speculation about risk factors and the new findings relating to geographical region and family links give us avenues to pursue in understanding and avoiding the condition."
The study, published in the Veterinary Record, was funded by the Kennel Club Charitable Trust. The Roslin Institute receives strategic funding from the Biotechnology and Biological Sciences Research Council.