Leading edge vortex allows bats to stay aloft

A simplified representation of the strong vortices associated with the unsteady aerodynamics of bat flight at slow speeds. The vortices can be thought of as causing the surrounding air to rotate rapidly around them and this motion around the LEV on top of the wing increases the lift force on it. Just like familiar, fixed-wing planes, the bat also leaves tip vortices in its wake, but the overall flow is further modified by the start vortices created at the beginning of the downstroke. Credit: USC