Sticking together makes bacteria nearly invincible

Bacterial life is astonishingly varied. These single-celled organisms come as spheres, rods, spirals and corkscrews. A few are a centimetre long; most are tens of thousands of times smaller. They have been found on Mount Everest, in Antarctica, and deep within Earth’s crust. And yet virtually every bacterial species ever found shares one trait: its members do not like living alone.