Bacteria vote on when to act using a chemical language, then commit all at once

Individual bacteria release small signalling molecules and can sense their own concentration in the surrounding fluid, effectively counting how many neighbours are nearby. Once that count crosses a threshold, the whole population switches on behaviours together, like glowing or forming a biofilm, that would be useless coming from a single cell alone. Bonnie Bassler's work on light-producing marine bacteria helped establish this 'quorum sensing' as a general feature of bacterial life.

— Bonnie Bassler, Quorum Sensing in Bacteria — Annual Review of Microbiology, 2001