In Brief

7 October 2015

Slow cyclists gain advantage from schooling like fish


Pelotons are groups of cyclists that form during mass-start races. Hugh Trenchard, a former competitive cyclist and self-taught physicist, produced computer simulations of various pelotons to study them.

He found that they change from roughly circular to single file as the front rider speeds up. The peloton stays united because slower cyclists get an energy boost from the slipstream of riders ahead of them. Only if this boost isn’t enough to compensate for these riders’ lower top speed does the peloton begin to fragment. Taken together, this means that the shape and size of the peloton is determined by each cyclist’s individual speed (Applied Mathematics and Computation,

Trenchard calls this “protocooperative behaviour” because it emerges when individuals work together unintentionally. He is now working with biologists to study whether his model applies to schools of fish when they flee predators.