The next time you hear someone use the term “sheeple”, know they haven’t kept up with the latest science and are engaging in the thoughtless following of which they accuse our woolly friends. A new study of sheep behavior indicates they display collective intelligence that humans – scientists and citizens alike – might do well to learn from.
Then again, every now and then it all goes rather badly – such as the sheep in inner Mongolia filmed walking in a circle for days, apparently unable to break free.
The popular image of social species tends to involve leaders and followers, with hierarchical arrangements not out of place in feudal Europe. Science has been slowly demolishing these portrayals, revealing that species such as wolves and baboons are actually quite democratic in their processes. Now it seems even sheep, supposedly such mindless followers, seize the initiative when the time is right. Oddly, this finding is published in the journal Nature Physics.
Professor Fernando Peruani of the Université Côte d’Azur and co-authors investigated the movements of several flocks of 2-4 sheep, all composed of females of the same age, to investigate theories of flocking as a self-organizing process. Movements were tracked from a nearby tower. They found that sheep alternate between grazing and moving to pastures greener as collective behavior, with the authors writing that “Each motion episode has a temporal leader that guides the group in line formation.” The leader varies randomly.
Whether sheep do this in larger flocks, or when there are rams present, is not known.
The likely reason sheep rotate, rather than always looking to the same leader, is that it allows them to take advantage of different flock members’ knowledge. If one sheep notices the grass is greener on the other side of a fence with an open gate, they will lead the flock through – if not at the first opportunity, then soon. Temporary leaders avoid the milling confusion we’ve all felt when a group of friends tries to work out where to have lunch.
Hierarchical structures fail when the trusted leader misses an opportunity and is too boneheaded to take advice. Moreover, sheep’s alternating leadership may reduce conflict – it’s much easier to accept a decision you don’t like if you know you’ll get another chance soon enough.
Although many species are known to move without leaders, attempts to model this behavior has been based on the Vicsek model. Inspired by murmurations of starlings, this shows how a few individuals, responding to information such as sensing a predator’s presence, can cause the whole flock to change course as if of the same mind.
However, in an accompanying editorial, Northwestern University’s Dr Cristian Huepe writes advanced versions of the Vicsek model have become; “victims of their own success,” getting applied to species that move in other ways.
Millions of years of evolution have provided us with an abundance of examples of ways to self-organize. Useful in designing collections of small robots, they could also open up more options for how we could organize ourselves.
By focusing only on a few examples, we’ve missed this diversity, something Peruani and co-authors are helping correct. That said, some species may be more of a warning on what not to do – locusts swarms’ movements are partly a product of cannibalism.
“Most collective motion studies, including experimental and theoretical ones, consider groups that remain, from the beginning till the end, on the move,” Peruani told Phys.org. Stop-start motion like that of sheep is more typical, but less studied.
Religious organizations have long encouraged their members to see themselves as sheep, watched over by God. Today flocks are often dwindling, who is to say whether learning from the real thing might be the answer?