Oil droplet predators chase oil droplet prey

Oil droplets can be made to act like predators, chasing down other droplets that flee like prey. The behavior, which is controlled by chemical signaling produced by the droplets, mimics behavior seen among living organisms but, until now, had not been recreated in synthetic systems. This tunable chemical system could potentially serve a model to help understand interactions in many-body systems such as schools of fish, bacterial colonies, or swarms of insects.