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The kinematics of hipposiderid bats (Hipposideros pratti) in straight and level flight has been deconstructed into a series of modes using proper orthogonal decomposition, to determine the relative importance of each mode in the overall force dynamics. Simplified kinematics have been reconstructed using different combinations of modes, and large eddy simulations were performed to compare the forces generated for each case. The first two modes (0,1) recovered only 62% of the lift, and manifested a drag force instead of thrust, whereas the first three modes (0,1,2) recovered 77% of the thrust and, unexpectedly, even more lift than the native kinematics. This demonstrates that mode 2, which features a combination of streamwise and chordwise cambering and twisting during the upstroke, is critical for the generation of lift, and more so for thrust. Detailed flow analyses reveal that the leading edge vortex and the trailing edge vortex hold the key to understanding this phenomenon. Such reduced order modeling of bat flight could provide guidelines for designing autonomous micro air vehicles which require a detailed understanding of the associated forces for the preservation of structural integrity.