The Gathering Swarms

Sardine Run in South Africa

The seasonal movement of billions of sardines along the coast of South Africa, the greatest fish migration on the planet, includes a stunning example of collective thinking to throw off predators. Synchronous movement by the sardines relies on a pressure sense that runs along their bodies to detect the movements of their nearest neighbors. Sardines are also able to use this pressure sense to detect predators, such as sharks, dolphins and whales. When a pod of dolphins and a flock of cape gannets make an attempt at feeding, the sardines are able to elude their would-be predators via collective movements.

The Gathering Swarms premieres Wednesday, May 21, 2014, at 8/7c on PBS.