Unexpected, epic badger journeys could shed light on bovine TB spread

18 Nov 2019813 Views

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While badgers typically stay close to home, Irish researchers have found that some travelled on epic journeys before settling down.

While a protected species in Ireland, badgers can easily harbour and spread tuberculosis (TB), which can then spread to cattle. Each year, many cows are culled after picking up the disease, costing farmers millions of euro.

One of the best ways of protecting cows against TB is by vaccinating badgers, requiring us to know how they move around in a given location. Now, researchers from Trinity College Dublin (TCD) have published a study in Ecology and Evolution that tracked the movement of 139 wild badgers to reveal that some travelled on unexpected, epic journeys.

As social animals, badgers typically live close together in shared territories. However, a badger will sometimes move from one living group to another in a different location, known as dispersal.

Map showing a badger's movement between different social groups.

The dispersal movements of a badger nicknamed Tiffin during a two-week period show she moved 66km from the territory in red to the one in stippled black via more than 20 other social group territories. Image: TCD

Staying close to mammy

Of the badgers monitored using GPS, only 17pc dispersed, showing their typical affinity for staying local. However, 80 of the badgers that did travel – particularly the females – could travel as far as 100km to find a new home.

“Our record-holder was a female that settled down only 1.5km away from where she was born, but travelled 308km back and forth before she joined her new social group,” said Aoibheann Gaughran, lead author of the study.

“Male badgers, on the other hand, liked to stay close to their mammy and typically just moved next door. Dispersal begins when badgers are aged one year or older, but by vaccinating them as cubs we can avoid the disease-spreading implications of this behaviour.”

The zoologists hope that by better understanding when and how badgers move between territories, they will be able to pinpoint where the greater risks for TB transmission lie, which would be extremely valuable information from a disease control perspective.

The Department of Agriculture, Food and the Marine announced earlier this year that it was rolling out a national programme to vaccinate badgers against TB.

Colm Gorey is a senior journalist with Siliconrepublic.com

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