The oceans are full of animals that seek safety in numbers, gathering together to confuse predators. But some opt for the opposite strategy.

As chains, Alexandrium swims and grows faster, but it is vulnerable to predators such as copepods – small relatives of crabs or shrimp. Erik Selander from theTechnical University of Denmark found that when the chains detect the chemical traces of copepods, they break apart. By turning back into single cells, they make themselves harder to find. They also swim at a slower pace to avoid creating telltale movements in the water. When threatened by predators, these plankton enter stealth mode.

Dawn Vaughan and Richard Strathmann found that if a pluteus detects the smell of a fish, it clones itself