Do Proximate Micro-Swimmers Synchronize their Gait?
  In this fluid dynamics video, we show that low Reynolds number swimmers, such as Caenorhabditis (C.) elegans, synchronize their gait when swimming in close proximity to maximize utilization of space. Synchronization most likely results from steric hindrance and enhances the propulsive speed only marginally. 
Jinzhou Yuan, Kun He Lee, David M. Raizen, and Haim H. Bau
physics.flu-dyn physics.bio-ph