July 24, 2012
Sheep Prove That Selfish Herding Theory Is True
[ Watch the Video ]
redOrbit Staff & Wire Reports - Your Universe Online
Many animals spend time together in herds for protection and not because they 'like' each other, according to a new study, which provides the first hard evidence that the "selfish herd theory" is true.
To prove this theory, researchers strapped GPS-enabled backpacks to flocking sheep and a herding dog.
"We were able to track the movements of the sheep and the dog that pursued them on a second-by-second basis simultaneously," said Andrew King of The Royal Veterinary College, University of London. "In each case, we found that the sheep exhibit a strong attraction towards the center of the flock as the dog approaches," an effort to avoid the more dangerous perimeter.
According to a Cell Press statement regarding the study, "The selfish herd has long been a favorite explanation for grouping behavior...But tracking the concerted movements of many individual animals at once and predicting a predator's attack is not easy to do. As a result, there had been little appearance of proof."
The new data suggests that, when threatened, sheep move continuously toward the center of the flock while the flock as a whole moves away from the threat. "It's kind of continuously folding in on itself," King says. The researchers then used simple math to recreate that folding pattern.
Some members of the flock seem to come out better than others, King added. The researchers can't say yet whether this is from luck or ability, though they are giving the sheep physical fitness and personality tests to look for predictable patterns. They also want to sort out the "rules" the sheep follow in order to move in such an amazing and orchestrated way.
It turns out the new findings might even shed light on neurodegenerative diseases such as Huntington's, King says, noting that sheep are a popular model for the study of that devastating human condition. "We wanted to establish a baseline of 'normal' sheep social behavior, from which others can pinpoint the onset and progression of abnormal behaviors that may be associated with locomotor or cognitive deficits," King says.
The results of the research is published in the July 24 issue of Current Biology.