A bacterial species that hunts other bacteria has attracted great interest as a potential living antibiotic, but exactly how this predator tracks down its prey has not been clear. A study published March 28 in Biophysical Journal sheds light on this question, revealing that the bacterial predator Bdellovibrio bacteriovorus (BV) homes in on its target by taking advantage of fluid forces generated by its own swimming movements and those of its prey. These hydrodynamic flow fields bring the bacteria in close proximity, giving BV a greater chance of successful attack.