Promiscuous badgers that 'sleep around' are spreading bovine tuberculosis, according to a team of academics from Cornwall.
Sleeping away from the family home is linked to health risks for badgers, reveals the new research by scientists at the University of Exeter's Tremough Campus at Falmouth.
Researchers working with the Food and Environment Research Agency found that badgers which strayed away from the family home in favour of sleeping in outlying setts were more likely to carry TB.
The 12-month study of 40 wild badgers was funded by the Department for Environment, Food and Rural Affairs (Defra) and could have useful implications for the management of bovine TB.
With pilot culls of badgers in two South West bovine TB hot-spot areas scheduled for early next summer, the findings could prove useful.
The behaviour of individual animals is thought to be a key factor in how the disease is spread among animals and livestock.
The work was carried out by Dr Nicola Weber, of the University of Exeter's Cornwall Campus, who said: "At a time when stopping the spread of TB is vital for farming, it's crucial to understand all of the factors involved in the transmission of the disease. Our research found that some individual badgers are more likely to sleep in setts in the outskirts of their territory. These individuals may be coming into contact with other sources of infection more frequently, meaning they could be more likely to both contract and to spread the disease, either to other badgers or to cattle."
Dr Weber attached electronic surveillance collars to badgers from eight groups at Woodchester Park in Gloucestershire, where the badger population is naturally infected with TB. Scientists selected a sample of 40 badgers from across the groups to provide a representative sample of age and gender.
In the study, each group had a territory made up of one or two main setts, which are used as the primary year-round underground den. They also had between three and eight outlying setts, which were occupied less frequently. The badgers were monitored for 28 consecutive days per season for one year to investigate how patterns differed between individuals.
Professor Robbie McDonald, of the University of Exeter, said: "Badgers occupying outlying dens are most likely to be looking for a mate, or defending their group territories. We think they acquire infection as a result of living on the periphery and contacting more individuals from other social groups, rather than because they are ostracised as a result of contracting the disease.
"It would be valuable to test the relationship between behaviour and infection more thoroughly."
Last year bovine TB caused the death of 26,000 cattle, bringing anguish to farmers and costing the taxpayer millions of pounds in compensation.