In a moment, a herd of goats is circling, casually leafing through the undergrowth. In the next, his long ears twitch and his big golden eyes stare at them as they trot purposefully, picking up speed as they seem to be racing attentively to a specific destination. They are exhibiting behavior that scientists have observed for a long time in herding, herding and educating animals from baboons to fish.
It almost looks like the goats voted and decided together which way to go.
How creatures in the animal kingdom come to a decision together is a matter of perennial interest. Among some species, individuals weigh. Members of meerkat troops make calls and African wild dogs sneeze before the group moves, and they will only leave when enough individuals have demonstrated.
It has already been postulated that African buffaloes vote with their movements, with animals pointing to the path they want to follow and the herd choosing the average from all directions.
It is difficult, however, for a human observer to distinguish between incursions directed by silent voting and those in which animals copy everything that their closest countrymen are doing, like school fish. Using collars equipped with GPS and other sensors, biologists observed a small herd of Namibian goats to see if their behavior suggested one tactic or another. In an article published Wednesday in the Royal Society Open Science magazine, they report that the goats do not appear to be voting.
If animals decide in advance which way to go, there must be a gap between when most people turn in the direction of travel and when they leave, said Andrew King, who studies animal behavior at Swansea University in Wales and is a author of the new role. But it can be difficult for researchers to identify the moments that matter.
“If you just sat in the field with a notebook, you wouldn’t be able to because you don’t know when they are leaving,” he said.
He and his colleagues developed collars containing GPS equipment, as well as accelerometers and magnetometers that track the direction of animals, when they start moving together and where they finally stop. They placed the collars on 16 domesticated goats in the Tsaobis Nature Park in Namibia and collected data while roaming for 10 days. With that information, they could go back to the point before the group left a particular location and determine when they turned to their destination.
If the vote was taking place, the goats would orient themselves before the movement started. Most may be facing the direction in which they eventually move, or the direction may be an average of their positions. In each situation, there would be a delay before the goats acted according to the decision.
Instead, what the researchers saw was that the goats did not begin to face their destiny until the moment they left. This implied that a goat would begin to move, its closest neighbors would turn to follow it and its closest neighbors would do the same, a behavior that researchers call a copy. This meant that the orientation of the goats before an incursion did not predict which way they would go.
The researchers also built a computer model to simulate how the goats would move if they were voting instead of just copying. Some herds of virtual goats were programmed to copy their neighbors, while others voted with their positions. The researchers found that what the goats did in real life looked much more like the imitation herds, suggesting that the animals need do nothing more than imitate their companions to move as a group.
The behavior that emerges from very simple rules can be surprisingly complex. Goats may not be arguing – at least not what the scientists saw in this study – but that does not mean that their ways of moving together are not flexible or useful. If more research confirms that they are moving by copying, it may indicate that imitating neighbors can improve the survival of a herd, as well as other good results most of the time.
Dr. King said that if many unrelated species use this decision-making process instead of voting, “it probably means that it is a useful and adaptable way of making collective decisions.”