Discovery of ‘super-ranging’ badgers offers ‘opportunity’ to fight against TB

A ‘super-ranging’ behaviour in badgers has been newly discovered by a team of Irish researchers – which could have a major impact on how bovine tuberculosis (TB) vaccination programmes are implemented.

The multi-disciplinary research team – comprised of zoologists from Trinity College Dublin – has worked with veterinarians and ecologists from the Department of Agriculture, Food and the Marine and the National Parks and Wildlife Service (NPWS).

In the research, just published in the international journal PLOS ONE, the team uncovered ‘super-ranging’ badgers – males that range between two and three times more widely than typical badgers in social groups. They generally live in more rigid territories.

In this study, around 22% of males adopted this super-ranging behaviour.

Aoibheann Gaughran, PhD researcher at Trinity’s School of Natural Sciences, and lead author on the paper said: “Normally, badgers don’t venture too far beyond the boundaries of their territories, which sometimes last for decades, and are clearly marked at the borders by latrines. Badgers may actively defend these territories if others intrude.”

By using GPS satellite trackers to take a uniquely personal look at the nightly comings and goings of almost 50 badgers in the wild, we discovered that some males completely ignore the traditional territory boundaries.

“Instead they range far into areas that encompass the territories of other social groups as well. We are not sure why they do this, but we know they can hold these super-ranges for several years and they presumably gain access to a greater number of female badgers than if they stayed at home.”

Speaking to AgriLand, Gaughran explained: “While it’s a new discovery in terms of the strategy that badgers use in their ranging, I’m not saying that badgers are actually ranging further than they were before, that is a complete misunderstanding.

“What we’re saying is that there are badgers acting in two different ways. And that understanding really helps us understand any pathway that the disease might be able to take.

“Therefore, we can better get a handle on how diseases spread and then also how to control the disease. So, for example, we can take the knowledge that there are these badgers out there ranging in this way and we can target these individuals with the vaccination programme that has recently been announced and with future vaccination programmes that would include for example oral baiting of badgers with vaccines.

So it basically means that, the more understanding we have about badger behaviour, the better able we are to combat the disease – and ultimately that’s going to help farmers in terms of getting a handle on TB in the country.

On the topic of what farmers themselves can do regarding limiting disease transfer, Gaughran said: “Most farmers from my experience are very au fait with how to protect their farms and I think one thing that would be really important would be that they practice really good biosecurity measures.

“If they have a sett on their land, we would always recommend that they fence that sett off from cattle. And also, if they have latrines on their land as well, that they fence those latrines off from cattle, so that they prevent any kind of indirect interaction between the animals.

“Our research has shown that badgers will avoid cattle in pasture and they’ll avoid cattle farmyards, but farmers can also help to minimise the contact out in pasture as well.

“It is important to say that nearly 90% of badgers in the country do not have TB – and one thing I’d like to point out about the super-rangers in our paper is that they were healthy.

So this discovery is not something that should be alarming for farmers; rather it should be looked on as an opportunity to help us control the disease through vaccination.