GPS backpacks reveal sheep flocking strategy

UK researchers have shown for the first time that instead of fleeing randomly when faced with danger, sheep head straight for the centre of the flock.

Understanding this behaviour in healthy animals may help researchers understand the breakdown in social behaviours caused by neurological disorders in sheep, as well as those in humans, such as Huntington’s disease.

"Sheep must be attuned to their neighbours’ reactions to be able to flock like this. We are now using our approach to understand the breakdown of group behaviours that may occur when sheep are injured, ill, or have diseases. Having an understanding of normal behaviour means that changes in behaviour can be linked to the progress of neurological diseases such as Huntington’s disease," says Professor Jenny Morton from the University of Cambridge, co-author of the study, published in Current Biology this week.

The findings support a 40-year-old idea put forward by evolutionary biologist Bill Hamilton. He suggested that creatures as different as insects, fish and cattle all react to danger by moving towards the middle of their respective swarms, schools or herds.

"Scientists agree that flocking behaviour has evolved in response to the risk of being attacked by predators. The idea is that being part of a tight-knit group not only increases the chances that you might spot a predator, but decreases the chance that you are the one the predator goes for when it attacks," explains Andrew King from The Royal Veterinary College (RVC), lead author the study.

Scientists call this the selfish herd theory - individuals benefit from being in a herd, because they can control where they are relative to their group-mates and any potential predator. This ends up lowering the likelihood of being grabbed by a big, hungry mouth.