Researchers at Swansea University have developed a new model that has helped to explain the relationship between a shepherd and his sheepdog.

They used GPS data to build a computer model which reveals the mathematical secrets to find out that how a single dog does is able to move 100 sheep so efficiently in the same direction.

Dr. Andrew King of Swansea University designed backpacks fitted with highly accurate GPS technology. The packs were then attached to a flock of 46 merino sheep and a sheepdog female in a five-hectare (12-acre) field.

The answer was revealed on Tuesday in a journal published by Britain's prestigious Royal Society.

It was found that the dog follows a simple thumb rule to bind the sheep together by weaving around side-to-side at their backs and once this has been achieved, it drives the group forward.

Daniel Stroembom of Uppsala University in Sweden said, "At every step in the model, the dog decides if the herd is cohesive enough or not. If not cohesive, it will make it cohesive, but if it's already cohesive, the dog will push the herd towards the target."

Single sheep dogs can successfully herd flocks of 80 or more sheep during their everyday work and in competitive herding trials.

There are numerous applications for this knowledge, which includes crowd control, cleaning up the environment, herding of livestock, keeping animals away from sensitive areas and collective or guiding groups.

There is no doubt that this model could be used to help develop "shepherd robots", for controlling crowds or cleaning up an oil spill.