Supplementary Video 1 from Flagellar bending affects macroscopic properties of bacterial suspensions PotomkinM. TournusM. BerlyandL. V. AransonI. S. 2017 To survive in harsh conditions, motile bacteria swim in complex environments and respond to the surrounding flow. Here, we develop a mathematical model describing how flagellar bending affects macroscopic properties of bacterial suspensions. First, we show how the flagellar bending contributes to the decrease in the effective viscosity observed in dilute suspension. Our results do not impose tumbling (random reorientation) as was previously done to explain the viscosity reduction. Second, we demonstrate how a bacterium escapes from wall entrapment due to the self-induced buckling of flagella. Our results shed light on the role of flexible bacterial flagella in interactions of bacteria with shear flow and walls or obstacles.