Leading the pack in following the herd

A few in the know can lead the many, according to new research into travelling animal groups carried out by the universities of Leeds and Oxford. Crowds of Leeds biology undergraduates will be observed to test their theory later this year.

Large groups of animals such as bees, fish, sheep and birds have to make collective decisions about which direction to take, although only a few individuals know the route. Some animals use signals to communicate, such as the honeybee’s famous ‘waggle-dance’. But such signals don’t work in large groups because individuals can only see the animals closest to them.

Leeds professor in behavioural ecology Jens Krause and Oxford biologist Dr Iain Couzin created a computer model based on observations of animals to show how information is shared. They looked at groups which don’t use signalling or have a leader. The model revealed that the larger the group, the smaller the proportion of informed animals needed to guide it, and only a small proportion of animals in the know is needed for accuracy. Animals are capable of agreeing which way to go when informed individuals in the group have different preferences about which way to travel, even though these individuals don’t know if they are in the majority or minority.

Professor Krause said: “We want to go on now and look at what happens when there is conflict in the group and we’ll be testing it using fish – sticklebacks and guppies – and undergraduate students at Leeds.

“We’ll look at how information transmission takes place in human crowds when it comes to choosing a direction, particularly if there are differences in the group, and how these conflicts are settled.” Their work was published in Nature this month.